Just Another Linux Lover Blog

Handling nginx Failover With KeepAlived

2010-02-26T10:56:00.000-08:00

How do configure to release and obtain VIP (virtual IP) when nginx is dead, down or system is rebooted for the kernel upgrades?

Edit /usr/local/etc/keepalived/keepalived.conf and add the following section to check whether nginx is alive or dead:
# vi /usr/local/etc/keepalived/keepalived.conf

Updated file on both lb0 and lb1:

vrrp_script chk_http_port {
script "/usr/bin/killall -0 nginx"
interval 2
weight 2
}
vrrp_instance VI_1 {
interface eth0
state MASTER
virtual_router_id 51
priority 101
authentication {
auth_type PASS
auth_pass Add-Your-Password-Here
}
track_script {
chk_http_port
}
virtual_ipaddress {
202.54.1.1/29 dev eth1
}
}

Save and close the file. Reload keealived:
# /etc/init.d/keepalived restart

If nginx died due to any issues keepalived will release master VIP and backup server will become active. When master nginx LB0 comes backs online, the backup LB1 will go down in backup state.

CentOS / Redhat: Install nginx As Reverse Proxy Load Balancer

2010-02-26T10:49:00.001-08:00

How do I configure nginx as failover reverse proxy load balancer in front of two Apache web servers under CentOS / RHEL 5.x?

nginx is a Web and Reverse proxy server. Nginx used in front of Apache Web servers. All connections coming from the Internet addressed to one of the Web servers are routed through the nginx proxy server, which may either deal with the request itself or pass the request wholly or partially to the main web servers.

Our Sample Setup
Internet--
|
============= |---- apache1 (192.168.1.15)
| ISP Router| |
============= |---- apache2 (192.168.1.16)
| |
| |---- db1 (192.168.1.17)
| |eth0 -> 192.168.1.11 ----------/
|-lb0==| /
| |eth1 -> 202.54.1.1 ----/
|
| |eth0 -> 192.168.1.10 ----------\
|-lb1==| / |---- apache1 (192.168.1.15)
|eth1 -> 202.54.1.1 ----/ |
|---- apache2 (192.168.1.16)
|
|---- db1 (192.168.1.17)
Where,

lb0 - Linux box directly connected to the Internet via eth1. This is master load balancer.
lb1 - Linux box directly connected to the Internet via eth1. This is backup load balancer. This will become active if master networking failed.
202.54.1.1 - This ip moves between lb0 and lb1 server. It is called virtual IP address and it is managed by keepalived.
eth0 is connected to LAN and all other backend software servers are connected via eth0.
nginx is installed on both lb0 and lb1. It will listen on 202.54.1.1. You need to configure nginx as reverse proxy server. It will connects to Apache1 and Apache2.
Install httpd server on Apache#1 and Apache#2 server. Configure them to listen on 192.168.1.15:80 and 192.168.1.16:80. Do not assign public IP to this box. Only activate eth0 via LAN.
Install MySQL / Oracle / PgSQL server on Db#1. Configure db server to listen on 192.168.1.17:$db_server_port. Do not assign public IP to this box. Only activate eth0 via LAN.
In short you need the following hardware:

2 load balancer reverse proxy servers (250GB SATA, 2GB RAM, Single Intel P-D930 or AMD 170s with RHEL 64 bit+keepalived+nginx)
2 Apache web servers (Software RAID-1, SCSI-73GBx2 15k disk, 6GB RAM, Dual Intel Xeon or AMD 64 bit CPU with RHEL 64 bit+Apache 2)
1 backup Apache web servers (Software RAID-1, SCSI-73GBx2 15k disk, 6GB RAM, Dual Intel Xeon or AMD 64 bit CPU with RHEL 64 bit+Apache 2)
1 database server (RAID-10, SCSI-73GBx4 15k disk, 16GB RAM, Dual Intel Xeon or AMD 64 bit CPU with RHEL 64 bit+MySQL 5)
1 Caching server (RAID-1, SCSI-73GBx2 15k disk, 8GB RAM, Dual Intel Xeon or AMD 64 bit CPU with RHEL 64 bit)
1 offsite backup server (RAID-6, 1TB SATAx4, 4GB RAM, Single Intel/AMD CPU with RHEL 64bit)
Slave database, storage, pop3 and SMTP server as per requirements.
Internet uplink 100Mbps+ or as per requirements.
Remove Unwanted Software From lb0 and lb1
Type the following commands:
# yum -y groupremove "X Window System"
# x=$(yum list installed | egrep -i 'php|httpd|mysql|bind|dhclient|tftp|inetd|xinetd|ypserv|telnet-server|rsh-server|vsftpd|tcsh' | awk '{ print $1}')
# yum -y remove $x
# yum -y install bind-utils sysstat openssl-devel.x86_64 pcre-devel.x86_64 openssl097a.x86_64
# /usr/sbin/authconfig --passalgo=sha512 --update
# passwd root

The above will remove X windows and other unwanted software from both lb0 and lb1.

Install Nginx On Both lb0 and lb1
Type the following commands to download nginx, enter:
# cd /opt
# wget http://sysoev.ru/nginx/nginx-0.8.33.tar.gz

Untar nginx, enter:
# tar -zxvf nginx-0.8.33.tar.gz
# cd nginx-0.8.33

Configure nginx for 64 bit RHEL / CentOS Linux:
# ./configure --without-http_autoindex_module --without-http_ssi_module --without-http_userid_module --without-http_auth_basic_module --without-http_geo_module --without-http_fastcgi_module --without-http_empty_gif_module --with-openssl=/lib64

Sample outputs:

....
nginx path prefix: "/usr/local/nginx"
nginx binary file: "/usr/local/nginx/sbin/nginx"
nginx configuration prefix: "/usr/local/nginx/conf"
nginx configuration file: "/usr/local/nginx/conf/nginx.conf"
nginx pid file: "/usr/local/nginx/logs/nginx.pid"
nginx error log file: "/usr/local/nginx/logs/error.log"
nginx http access log file: "/usr/local/nginx/logs/access.log"
nginx http client request body temporary files: "client_body_temp"
nginx http proxy temporary files: "proxy_temp"
nginx http fastcgi temporary files: "fastcgi_temp"
...
Install the same:
# make
# make install

Create nginx User Account
Type the following commands to create a user account:
# useradd -s /sbin/nologin -d /usr/local/nginx/html -M nginx
# passwd -l nginx

Configure nginx As Reverse Proxy Load Balancer On Both lb0 and lb1
Edit /usr/local/nginx/conf/nginx.conf, enter:
# vi /usr/local/nginx/conf/nginx.conf

Update it as follows:

pid logs/nginx.pid;
user nginx nginx;
worker_processes 10;

events {
worker_connections 1024;
}

http {
default_type application/octet-stream;

## Common options ##
include options.conf;

## Proxy settings ##
include proxy.conf;

## lb domains ##
include nixcraft.in.conf;
}
Edit /usr/local/nginx/conf/options.conf, enter:
# vi /usr/local/nginx/conf/options.conf

Update it as follows:

## Size Limits
client_body_buffer_size 128K;
client_header_buffer_size 1M;
client_max_body_size 1M;
large_client_header_buffers 8 8k;

## Timeouts
client_body_timeout 60;
client_header_timeout 60;
expires 24h;
keepalive_timeout 60 60;
send_timeout 60;

## General Options
ignore_invalid_headers on;
keepalive_requests 100;
limit_zone gulag $binary_remote_addr 5m;
recursive_error_pages on;
sendfile on;
server_name_in_redirect off;
server_tokens off;

## TCP options
tcp_nodelay on;
tcp_nopush on;

## Compression
gzip on;
gzip_buffers 16 8k;
gzip_comp_level 6;
gzip_http_version 1.0;
gzip_min_length 0;
gzip_types text/plain text/css image/x-icon application/x-perl application/x-httpd-cgi;
gzip_vary on;

## Log Format
log_format main '$remote_addr $host $remote_user [$time_local] "$request" '
'$status $body_bytes_sent "$http_referer" "$http_user_agent" '
'"$gzip_ratio"';

Edit /usr/local/nginx/conf/proxy.conf, enter:

## Proxy caching options
proxy_buffering on;
proxy_cache_min_uses 3;
proxy_cache_path /usr/local/nginx/proxy_temp/ levels=1:2 keys_zone=cache:10m inactive=10m max_size=1000M;
proxy_cache_valid any 10m;
proxy_ignore_client_abort off;
proxy_intercept_errors on;
proxy_next_upstream error timeout invalid_header;
proxy_redirect off;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_connect_timeout 60;
proxy_send_timeout 60;
proxy_read_timeout 60;

Edit /usr/local/nginx/conf/nixcraft.in.conf, enter:

## Connect to backend servers via LAN ##
## Reverse Proxy Load Balancer Logic ##
upstream nixcraft {
server 192.168.1.15 weight=10 max_fails=3 fail_timeout=30s;
server 192.168.1.16 weight=10 max_fails=3 fail_timeout=30s;
# only comes alive when above two fails
server 192.168.1.23 weight=1 backup;
}

server {
access_log logs/access.log main;
error_log logs/error.log;
index index.html;
root /usr/local/nginx/html;
server_name nixcraft.in www.nixcraft.in subdomain.nixcraft.in;

## Only requests to our Host are allowed
if ($host !~ ^(nixcraft.in|www.nixcraft.in|subdomain.nixcraft.in)$ ) {
return 444;
}

## redirect www to nowww
# if ($host = 'www.nixcraft.in' ) {
# rewrite ^/(.*)$ http://nixcraft.in/$1 permanent;
# }

## Only allow these request methods
if ($request_method !~ ^(GET|HEAD|POST)$ ) {
return 444;
}

## PROXY - Web
location / {
proxy_pass http://nixcraft;
proxy_cache cache;
proxy_cache_valid 200 24h;
proxy_cache_use_stale error timeout invalid_header updating http_500 http_502 http_503 http_504;
proxy_ignore_headers Expires Cache-Control;

proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
}

# redirect server error pages to the static page /50x.html
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
Start nginx web server:
# /usr/local/nginx/sbin/nginx
# netstat -tulpn | grep :80
# echo ' /usr/local/nginx/sbin/nginx' >> /etc/rc.local

Fire a webbrowser and type domain name such as nixcraft.in:
http://nixcraft.in

References:
nginx wiki
Stay tuned, for rest of the firewall, security, SELinux, database, helper scripts and optimization configuration.

CentOS / Redhat Linux: Install Keepalived To Provide IP Failover For Web Cluster

2010-02-26T10:33:00.000-08:00

Keepalived provides a strong and robust health checking for LVS clusters. It implements a framework of health checking on multiple layers for server failover, and VRRPv2 stack to handle director failover. How do I install and configure Keepalived for reverse proxy server such as nginx or lighttpd?

If your are using a LVS director to loadbalance a server pool in a production environment, you may want to have a robust solution for healthcheck & failover. This will also work with reverse proxy server such as nginx.

Our Sample Setup
Internet--
|
=============
| ISP Router|
=============
|
|
| |eth0 -> 192.168.1.11 (connected to lan)
|-lb0==|
| |eth1 -> 202.54.1.1 (vip master)
|
| |eth0 -> 192.168.1.10 (connected to lan)
|-lb1==|
|eth1 -> 202.54.1.1 (vip backup)
Where,

lb0 - Linux box directly connected to the Internet via eth1. This is master load balancer.
lb1 - Linux box directly connected to the Internet via eth1. This is backup load balancer. This will become active if master networking failed.
202.54.1.1 - This ip moves between lb0 and lb1 server. It is called virtual IP address and it is managed by keepalived.
eth0 is connected to LAN and all other backend software such as Apache, MySQL and so on.
You need to install the following softwares on both lb0 and lb1:

keepalived for IP failover.
iptables to filter traffic
nginx or lighttpd revers proxy server.
DNS settings should be as follows:

nixcraft.in - Our sample domain name.
lb0.nixcraft.in - 202.54.1.11 (real ip assigned to eth1)
lb1.nixcraft.in - 202.54.1.12 (real ip assigned to eth1)
www.nixcraft.in - 202.54.1.1 (VIP for web server) do not assign this IP to any interface.
Install Keepalived
Visit keepalived.org to grab latest source code. You can use the wget command to download the same (you need to install keepalived on both lb0 and lb1):
# cd /opt
# wget http://www.keepalived.org/software/keepalived-1.1.19.tar.gz
# tar -zxvf keepalived-1.1.19.tar.gz
# cd keepalived-1.1.19

Install Kernel Headers

You need to install the following packages:

Kernel-headers - includes the C header files that specify the interface between the Linux kernel and userspace libraries and programs. The header files define structures and constants that are needed for building most standard programs and are also needed for rebuilding the glibc package.
kernel-devel - this package provides kernel headers and makefiles sufficient to build modules against the kernel package.
Make sure kernel-headers and kernel-devel packages are installed. If not type the following install the same:
# yum -y install kernel-headers kernel-devel

Compile keepalived

Type the following command:
# ./configure --with-kernel-dir=/lib/modules/$(uname -r)/build

Sample outputs:

checking for gcc... gcc
checking for C compiler default output file name... a.out
checking whether the C compiler works... yes
checking whether we are cross compiling... no
checking for suffix of executables...
checking for suffix of object files... o
...
.....
..
config.status: creating keepalived/check/Makefile
config.status: creating keepalived/libipvs-2.6/Makefile

Keepalived configuration
------------------------
Keepalived version : 1.1.19
Compiler : gcc
Compiler flags : -g -O2
Extra Lib : -lpopt -lssl -lcrypto
Use IPVS Framework : Yes
IPVS sync daemon support : Yes
Use VRRP Framework : Yes
Use Debug flags : No
Compile and install the same:
# make && make install

Create Required Softlinks

Type the following commands to create service and run it at RHEL / CentOS run level #3 :
# cd /etc/sysconfig
# ln -s /usr/local/etc/sysconfig/keepalived .
# cd /etc/rc3.d/
# ln -s /usr/local/etc/rc.d/init.d/keepalived S100keepalived
# cd /etc/init.d/
# ln -s /usr/local/etc/rc.d/init.d/keepalived .

Configuration

Your main configuration directory is located at /usr/local/etc/keepalived and configuration file name is keepalived.conf. First, make backup of existing configuration:
# cd /usr/local/etc/keepalived
# cp keepalived.conf keepalived.conf.bak

Edit keepalived.conf as follows on lb0:

vrrp_instance VI_1 {
interface eth0
state MASTER
virtual_router_id 51
priority 101
authentication {
auth_type PASS
auth_pass Add-Your-Password-Here
}
virtual_ipaddress {
202.54.1.1/29 dev eth1
}
}
Edit keepalived.conf as follows on lb1 (note priority set to 100 i.e. backup load balancer):

vrrp_instance VI_1 {
interface eth0
state MASTER
virtual_router_id 51
priority 100
authentication {
auth_type PASS
auth_pass Add-Your-Password-Here
}
virtual_ipaddress {
202.54.1.1/29 dev eth1
}
}
Save and close the file. Finally start keepalived on both lb0 and lb1 as follows:
# /etc/init.d/keepalived start

Verify: Keepalived Working Or Not

/var/log/messages will keep track of VIP:
# tail -f /var/log/messages

Sample outputs:

Feb 21 04:06:15 lb0 Keepalived_vrrp: Netlink reflector reports IP 202.54.1.1 added
Feb 21 04:06:20 lb0 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 202.54.1.1
Verify that VIP assigned to eth1:
# ip addr show eth1

Sample outputs:

3: eth1: mtu 1500 qdisc pfifo_fast qlen 10000
link/ether 00:30:48:30:30:a3 brd ff:ff:ff:ff:ff:ff
inet 202.54.1.11/29 brd 202.54.1.254 scope global eth1
inet 202.54.1.1/29 scope global secondary eth1
ping failover test
Open UNIX / Linux / OS X desktop terminal and type the following command to ping to VIP:
# ping 202.54.1.1

Login to lb0 and halt the server or take down networking:
# halt

Within seconds VIP should move from lb0 to lb1 and you should not see any drops in ping. On lb1 you should get the following in /var/log/messages:

Feb 21 04:10:07 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) forcing a new MASTER election
Feb 21 04:10:08 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) Transition to MASTER STATE
Feb 21 04:10:09 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) Entering MASTER STATE
Feb 21 04:10:09 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) setting protocol VIPs.
Feb 21 04:10:09 lb1 Keepalived_healthcheckers: Netlink reflector reports IP 202.54.1.1 added
Feb 21 04:10:09 lb1 Keepalived_vrrp: VRRP_Instance(VI_1) Sending gratuitous ARPs on eth1 for 202.54.1.1
Conclusion

Your server is now configured with IP failover. However, you need to install and configure the following software in order to configure webserver and security:

nginx or lighttpd
iptables
Stay tuned, for more information on above configuration.

Auto mounting a Samba share in Linux

2010-02-22T23:57:00.000-08:00

So you have that Samba server up and running and you can connect to it from Windows and Mac with ease. But when you turn to another Linux box that doesn’t have Konqueror, Nautilus, or Dolphin you can’t figure out the riddle of connecting. Or maybe you want to have this share mounted at boot time? How do you manage it?From the command line of course. Yes there are plenty of GUI tools that will allow you to connect to a Samba share easily, but they don’t help you set up anything to connect automatically. For that you will need to employ a few command line tools. But once it is finished, your system will be seamless.

What you will need
First I am going to assume you have your Samba server set up and you are able to connect to it from other machines. Outside of that you will need only one piece of software installed on your Linux machine: smbclient. This will be in your distributions’ repositories so just open up your Add/Remove Software utility, search for smbclient, select it, and click Apply.
Once smbclient is installed you are ready to go.

A test
Let’s first test to make sure your Linux box can see the Samba share. You will need either sudo or root access to do this. Issue the command:
smbclient //IP_TO_SAMBA_SERVER/SHARE_NAME -U USERNAME
Where:

IP_TO_SAMBA_SERVER is the IP address of your Samba server.
SHARE_NAME is the share you want to connect to.
USERNAME is the user name you connect to the share with.

If all is well you should see something like this:
Enter wallenmusic’s password:
Domain=[MONKEYPANTZ] OS=[Unix] Server=[Samba 3.2.5]
smb: \>
If you see that you can type quit and then hit the Enter key to escape this prompt.

Setup
The first thing you need to do is create a directory to mount the Samba share to. I created the directory /data with the command:
sudo mkdir /data
Once that directory is created you can then mount it with the command:
mount -t smbfs -o username=USERNAME //IP_TO_SAMBA_SERVER/SAMBA_SHARE /data
Where:

IP_TO_SAMBA_SERVER is the IP address of your Samba server.
SHARE_NAME is the share you want to connect to.
USERNAME is the user name you connect to the share with.

Now if you check the /data directory you should see a listing of the contents of the Samba share.

Automount
Let’s make that share automount at boot. This will require editing your /etc/fstab file, adding an entry for this Samba share. In this file (again you will have to have either root or sudo access) you will add a line like this:
//IP_TO_SAMBA_SERVER/SAMBA_SHARE� /data smbfs username=USERNAME,password=PASSWORD, 0 0
Where:

IP_TO_SAMBA_SERVER is the IP address of your Samba server.
SHARE_NAME is the share you want to connect to.
USERNAME is the user name you connect to the share with.
PASSWORD is the password for the Samba user

Once that entry is saved unmount the /data directory with the command:
umount /data
so you can test your automount entry.
Now, enter the command:
mount -a
If there are no errors you should see the contents of the Samba share in the /data directory.
That’s it. Congratulations, you now have an automounted Samba share on your Linux machine.

Webmin: One Stop Linux Configuration

2010-02-22T23:52:00.000-08:00

Over the last ten+ years I have seen Linux configuration tools come and go. In the early days there was the tried-and-true, all-powerful linuxconf that many thought would remain the one and only Linux configuration tool until the end of times. Well, we were wrong and linuxconf has pretty much died off. Why did linuxconf die? Because new tools, such as Webmin? came along.
Webmin arrived on the scene in 1997 and pretty much blew away the competition. Webmin is truly a one-stop shop for Linux configuration. It’s modular so you can add and remove modules as they are needed. Webmin can configure your system, servers, networking, hardware, clusters, you name it!
Even though Webmin is a web-based utility, it does not require a server to be installed or running. Webmin contains its own built-in server so you will not need Apache running. Webmin does have to be running in order to log in.
The easiest way to install Webmin is to open up your Add/Remove Software utility, do a search for webmin, and install it. Or you can go to the Webmin Site, download the the appropriate binary and let your package manager do the work for you. If you are wanting to install Webmin on a headless server you can do the following:

Secure shell to your server
Download the correct installation file using the wget command.
Issue the command to install Webmin (such as rpm -ivh webmind-XXX.rpm (where XXX is the release number)

After the installation is complete you may have to start Webmin manually (the rpm installation starts the server for you). To start Webmin you will issue the command:

/etc/rc.d/init.d/webmin start

/etc/init.d/webmin start

Once you have started Webmin you log into it with with your browser by pointing it to:

http://IP_OR_DOMAIN:10000

Where IP_OR_DOMAIN is the IP address or the domain Webmin is installed on. If you are using it for local configuration you can point your browser to http://localhost:10000.

Webmin Main Page

As you can see, in the image to the left, the default Webmin page is very easy to navigate.Upon installation one of the first links you should click on this page is the Webmin link in the left navigation. When that menu expands you will see a number of entries, of which one is called Webmin Configuration.

The Webmin Configuration Page

Click on the Webmin Configuration option to reveal a number of possible choices. This section is very important because you will configure access, logging, certificates, categories, and a number of other critical features.
Make sure, however, when you make any changes to Webmin that restart the Webmin server. You can restart Webmin by clicking the Restart Webmin button that is at the bottom of the Webmin Configuration page.

Controlling Webmin

In the same area of the restart button there are a few other important options. If you know you are going to be using Webmin for all of your configuration needs you will want to make sure Webmin starts at boot.
Another important screen to visit, before you jump into various modules, is the Webmin Users screen. In this screen you can define groups and users and their various permissions for the Webmin system. Here you can define what modules a user or group has access to which can be very handy.
Once you get beyond Webmin basic configuration it is time to poke around the various modules. In later articles I will discuss some of the best of the Webmin modules.

Final Thoughts
Webmin is one of the most powerful administration tools available. If you haven’t experienced the power that is Webmin, install it now and see how much power you can have at your fingertips.

Adding a directory to your $PATH

2010-02-22T23:48:00.000-08:00

Image via Wikipedia

In the Linux operating system the $PATH is a listing of all directories where the system will look for commands. What this means is that all of the commands located in the directories included in your path will be globally executable. For example: The /usr/bin directory contains quite a lot of commands that can be excuted from within any directory on your system. Because of this you can issue the ls command from within any directory and get the listing of the contents of that directory. If the ls command wasn’t in a directory in your path you would have to include the explicite path to that command (i.e. /usr/bin/ls).
As a Linux user you can add directories to your $PATH. This is helpful when you don’t want to add a command to a directory in your $PATH but you want that command to be globally executable. Doing this is actually quite easy.

What is currently in your $PATH?
NOTE: This article applies only when you are using the Bash shell. To find out what directories are included in your current $PATH issue the command:

echo $PATH

You should see something like:

/usr/lib/qt-3.3/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/jlwallen/bin

Notice the /opt directory is missing. Often the /opt directory is a great place to “install” other applications for global use. But if this directory is not in your $PATH, you will always have to use the explicit path to call a command. With that in mind let’s add /opt.

.bash_profile
In order to add a directory you have to edit a file in your ~/ (home) directory. The .bash_profile file determines user specific environment and start up programs. This file also checks for a .bashrc file for aliases and functions, but that has nothing to do with your $PATH.
There is one particular line you need to examine in your .bash_profile:
PATH=$PATH:$HOME/bin
This is the line that determines anything extra in your $PATH. As you can see, in the example above, the extra directory added to the users’ $PATH is the ~/bin directory. Of course in most distributions this isn’t used (or even created during installation). Why ~/bin is still included I do not know. In order to add another directory to your $PATH in this line you would seperate the directories with a “:”. To add the /opt directory that line would now look like:

PATH=$PATH:$HOME/bin:/opt

As you can see the /opt directory has been added proceeding a “:”. Complete this addition and save the file. You’re not done yet.
If you issue the command echo $PATH you will still not see /opt in the users’ $PATH. Why? You have to log out and log back in before this change will take effect. So log out, log back in, and issue the command again. Issuing the command echo $PATH will not issue:

/usr/lib/qt-3.3/bin:/usr/kerberos/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/jlwallen/bin:/opt

Any command found in the /opt directory is now global.

Final thoughts
The $PATH is a very powerful tool to take advantage of in Linux. By using it you can install applications in directories outside of the norm and still make them global. I often install applications in the /opt directory or will create a /data directory for a more temporary application installation.

Howto Recover Grub2 After Windows Installation.

2010-02-18T03:30:00.000-08:00

You will need a LIVE cd if you are going to recover an Ubuntu Box.Download Ubuntu Jaunty, Karmic whatever you want.Open the system with Live CD (I assume you are using Ubuntu Live CD).Press Alt+F2 and enter gnome-terminal command.And continue by entering :

$sudo fdisk -l

This will show your partition table.Here is my table to understand it better :

/dev/sda1 29 8369 66999082+ 83 Linux
/dev/sda2 * 8370 13995 45190845 7 HPFS/NTFS
/dev/sda3 13996 14593 4803435 5 Extended
/dev/sda5 13996 14593 4803403+ 82 Linux swap / Solaris

Now i will mount Linux (sda1 here), i have no external boot partition as you can see.(IF YOU HAVE external one, do not forget to mount it! )

$sudo mount /dev/sda1 /mnt
$sudo mount --bind /dev /mnt/dev
$sudo mount --bind /proc /mnt/proc

The following command is optional (it copies resolv.conf)

$sudo cp /etc/resolv.conf /mnt/etc/resolv.conf

Now chroot into the enviroment we made :

sudo chroot /mnt

After chrooting, you do not need to add sudo before your commands because from now, you will run commands as root.

You may want to edit /etc/default/grub file to fit your system (timeout options etc)

#nano -w /etc/default/grub

Play with the options if you want.(But do not forget to give grub-update command if you saved it ;) )

Now install/recover Grub2 via :

#grub-install /dev/sda

command.However you may get errors with that code like me.If so please use this command :

#grub-install --recheck /dev/sda

Now you can exit the chroot, umount the system and reboot your box :

#exit
$sudo umount /mnt/dev
$sudo umount /mnt/proc
$sudo umount /mnt
$sudo reboot

Dear Windows, It's over

2010-02-17T07:49:00.000-08:00

Dear Windows Professional Service Pack 2:

I didn't want to tell you this in person, because I thought it might be too complicated, and might take too long. After all, we've been together for a long time, almost five years and running now. I know, i know. I know you so well; your control panel, your installation procedures, even when you get mad and go all blue screen on me; what can I say, you kinda grew on me.

But to be honest, things have been going downhill for a long time now. What happened to that lean, fast OS that i first installed? You know, the one that ran Civ 4, Vice City, and even True Crimes without a problem? The one that burned DVD's, CD's, the one that shared music with my xbox without a problem? I don't know. It seems like you've let go of yourself, to be honest. You take over 20 minutes to boot up, you run Civ4 slowly, heck, you even freeze up on me now when i try to watch video. What happened windows? Did you get so confortable that you thought I'd just deal with it?

Well, i've been cheating. See, back in tenth grade, i messed around a bit with this chick, her name was Red Hat Linux. We met in school in my networking 5 class, and i got to know her pretty well. I was all up in her terminal, if you know what i mean . Well, I took her home, and we had a really rough one night stand. I decided she wsn't for me, and i went back to you, because i knew what i was missing. Well, Red Hat has a south african cousin, and her name's Ubuntu...she's kinda hot, too. SHe's got three cousins, Xubuntu, Edubuntu, and Kubuntu, too, and their all sexy.

Well, I guess this letter is to let you know that it's over. I'm not going back, either. You can tempt me with your games, and all the software, but it's alright. I can get to know ubuntu, i can learn to work her terminals. Her freeware. Her internet support. After all, what can i say...she's sexy, fast, and free. ANd you're expensive, bloated, and well, always sick with viruses. I'm done.

I know, i know. I freaked out and formatted you off my hard drive, and then i called you begging and pleading to take me back, and we had angry make up sex. But what was i thinking? I remembered all the bad times we had, and i called Ubuntu up and she understood me just fine. Before I knew it, we were hitting it off again. She installed really quickly, and didn't even need any drivers or anything. Worked beautifully. And did i remind you she's free?

So Windows Professional Service Pack 2, i'm leaving you for Ubuntu know. It's over, we had a good run, but all expensive, virus laden, bloated software relationships must come to an end, right? I guess that's just how it has to be.

Thanks for all the good times though! NOthing like a BSOD when i'm trying to watch a live debate on MSN or CNN, or crashign on me int he middle of civ4.

But i have to go now. It's time to get down and dirty with ubuntu, and if i ever really miss you again, i'll just drink it away with some WINE.

Sincerely,

Bruno

Thanks for Ubuntuforums .

Maintaining MySQL Databases

2010-02-16T01:21:00.000-08:00

Posted on December 04th, 2009 in BeginLinux

As a MySQL administrator, you’ll probably end up doing some preventive and corrective database maintenance. You can use mysqlcheck for both.
First, consider the “virtual” database. It has one table called ‘accounts”. You can check the whole database with the following command:

mysqlcheck -p -u root virtual
Enter password:
virtual.accounts OK

Now, what if we just want to check one table of the database?

mysqlcheck -p -u root virtual trivia
Enter password:
virtual.accounts OK

As you can see, all you have to do to check just one table is to specify the table name after you specify the database name. Now, what if you have a database with more than two tables, and you want to check more than one, but not all of the tables? That’s easy. Just specify all of the tables that you want to check after you specify the database.

mysqlcheck -p -u root mysql db host proc
Enter password:
mysql.db                                           OK
mysql.host                                         OK
mysql.proc                                         OK

You can also check more than one database at a time. Let’s say that you want to check the “payroll” and the “contact” databases.

mysqlcheck -p -u root –databases payroll contact
Enter password:
payroll.last_name                                   OK
payroll.first_name                                  OK
payroll.SSN                                         OK
payroll.pay_rate                                    OK
contact.last_name                                   OK
contact.first_name                                  OK
contact.phone_number                                OK

This time, by adding the “–databases” switch, all names that you enter on the command-line will be treated as database names.
It’s also a simple matter to check all databases at once, just by using the “–all-databases” switch:

mysqlcheck -p -u root –all-databases
Enter password:
contacts.names                                     OK
contacts.phone_numbers                             OK
contacts.trivia                                    OK
mysql.columns_priv                                 OK
mysql.db                                           OK
mysql.func                                         OK
mysql.help_category                                OK
mysql.help_keyword                                 OK
mysql.help_relation                                OK
mysql.help_topic                                   OK
mysql.host                                         OK
mysql.proc                                         OK
mysql.procs_priv                                   OK
mysql.tables_priv                                  OK
mysql.time_zone                                    OK
mysql.time_zone_leap_second                        OK
mysql.time_zone_name                               OK
mysql.time_zone_transition                         OK
mysql.time_zone_transition_type                    OK
mysql.user                                         OK

You can also use mysqlcheck to perform corrective maintenance. There’s only one catch, though. MySQL databases can use two different types of tables–either MyISAM tables or InnoDB tables. While mysqlcheck can perform checks on either type of table, it can only repair MyISAM tables.

mysqlcheck -p -u root –repair virtual
Enter password:
virtual.accounts OK

You can do more extensive repairs by adding another switch:

mysqlcheck -p -u root –repair –extended virtual
Enter password:
virtual.accounts OK

Or, you can also do a quick repair:

mysqlcheck -p -u root –repair –quick virtual
Enter password:
virtual.accounts OK

How To Back Up MySQL Databases With mylvmbackup

2010-02-15T17:49:00.000-08:00

How To Back Up MySQL Databases With mylvmbackup On Debian Lenny

mylvmbackup is a Perl script for quickly creating MySQL backups. It uses LVM's snapshot feature to do so.

To perform a backup, mylvmbackup obtains a read lock on all tables and flushes all server caches to disk, creates a snapshot of the volume containing the MySQL data directory, and unlocks the tables again.

This article shows how to use it on a Debian Lenny server.

I do not issue any guarantee that this will work for you!

1 Preliminary Note
I'm assuming that MySQL is already set up and running on your system. The system must use LVM, and the MySQL data directory (/var/lib/mysql) should have an LVM partition of its own (althouth that is optional).

If you have read Back Up (And Restore) LVM Partitions With LVM Snapshots you know that LVM snapshots require some unused LVM partition for the snapshot.

My test system has a second, currently unused hard drive /dev/sdb that will be used by mylvmbackup to create a temporary logical volume for the backup.

This is my current situation:

root@server1:~# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/server1-root
20G 808M 18G 5% /
tmpfs 252M 0 252M 0% /lib/init/rw
varrun 252M 56K 251M 1% /var/run
varlock 252M 0 252M 0% /var/lock
udev 252M 2.6M 249M 2% /dev
tmpfs 252M 0 252M 0% /dev/shm
/dev/sda1 471M 23M 425M 6% /boot
/dev/mapper/server1-mysql
8.9G 170M 8.3G 2% /var/lib/mysql
root@server1:~#

As you see, I have two LVM partitions, / and /var/lib/mysql (plus an LVM swap partition not shown here).

The volume group is named server1, and the volumes are named swap, root, and mysql:

root@server1:~# pvdisplay
--- Physical volume ---
PV Name /dev/sda5
VG Name server1
PV Size 29.52 GB / not usable 3.66 MB
Allocatable yes (but full)
PE Size (KByte) 4096
Total PE 7557
Free PE 0
Allocated PE 7557
PV UUID 0gCmpE-FGel-9ayg-E2yg-kkEu-B72X-kFvaye

root@server1:~#

root@server1:~# vgdisplay
--- Volume group ---
VG Name server1
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 4
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 3
Open LV 3
Max PV 0
Cur PV 1
Act PV 1
VG Size 29.52 GB
PE Size 4.00 MB
Total PE 7557
Alloc PE / Size 7557 / 29.52 GB
Free PE / Size 0 / 0
VG UUID PH5Hpc-jqeP-BFYs-wWlA-hu03-qwuQ-0cNIu3

root@server1:~#

root@server1:~# lvdisplay
--- Logical volume ---
LV Name /dev/server1/swap
VG Name server1
LV UUID RCeLCK-MO5p-xoMq-SwTT-n2NV-GaP6-GaemDp
LV Write Access read/write
LV Status available
# open 2
LV Size 1.00 GB
Current LE 256
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:0

--- Logical volume ---
LV Name /dev/server1/root
VG Name server1
LV UUID 5Wen7n-xYmh-MQz1-fKH5-0XXa-1y2t-V3PYbb
LV Write Access read/write
LV Status available
# open 1
LV Size 19.53 GB
Current LE 5000
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:1

--- Logical volume ---
LV Name /dev/server1/mysql
VG Name server1
LV UUID wk8yb6-fDl8-4tg3-tneT-1dDe-wWdy-AfGZ5I
LV Write Access read/write
LV Status available
# open 1
LV Size 8.99 GB
Current LE 2301
Segments 1
Allocation inherit
Read ahead sectors auto
- currently set to 256
Block device 254:2

root@server1:~#

Here's an overview of my two hard drives:
root@server1:~# fdisk -l

Disk /dev/sda: 32.2 GB, 32212254720 bytes
255 heads, 63 sectors/track, 3916 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x0009353f

Device Boot Start End Blocks Id System
/dev/sda1 * 1 62 497983+ 83 Linux
/dev/sda2 63 3916 30957255 5 Extended
/dev/sda5 63 3916 30957223+ 8e Linux LVM

Disk /dev/sdb: 10.7 GB, 10737418240 bytes
255 heads, 63 sectors/track, 1305 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000

Disk /dev/sdb doesn't contain a valid partition table
root@server1:~#

2 Preparing /dev/sdb
Before we can create snapshots on /dev/sdb, we must partition it (Linux LVM) and add it to our volume group (server1).

I will now create the partition /dev/sdb1 and add it to the server1 volume group:

# fdisk /dev/sdb
server1:~# fdisk /dev/sdb

Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel Building a new DOS disklabel.

Changes will remain in memory only, until you decide to write them. After that, of course, the previous
content won't be recoverable.

The number of cylinders for this disk is set to 1305.

There is nothing wrong with that, but this is larger than 1024, and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)

Command (m for help): <-- n
Command action
e extended
p primary partition (1-4)
<-- p
Partition number (1-4): <-- 1
First cylinder (1-1305, default 1): <-- [ENTER]
Using default value 1
Last cylinder or +size or +sizeM or +sizeK (1-1305, default 1305): <-- [ENTER]
Using default value 1305

Command (m for help): <-- t
Selected partition 1
Hex code (type L to list codes): <-- 8e
Changed system type of partition 1 to 8e (Linux LVM)

Command (m for help): <-- w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.
pvcreate /dev/sdb1
vgextend server1 /dev/sdb1

That's it - we don't need to create any volumes on it - this will be done by mylvmbackup automatically.

3 Installing And Using mylvmbackup
Debian Lenny provides a package for mylvmbackup, therefore we can simply install it as follows:

# aptitude install mylvmbackup

Take a look at

# man mylvmbackup

to learn how to use it (read the part about InnoDB tables carefully if you're using InnoDB).

The mylvmbackup configuration file is /etc/mylvmbackup.conf, so you can either specify your options on the command line or in that file (command line options will override the options in /etc/mylvmbackup.conf).

The default backup directory is /var/cache/mylvmbackup/backup (unless you specify another location).

A sample command for backing up MyISAM tables would be:

# mylvmbackup --user=root --password=yourrootsqlpassword --mycnf=/etc/mysql/my.cnf --vgname=server1 --lvname=mysql --backuptype=tar

And for InnoDB:
# mylvmbackup --user=root --password=yourrootsqlpassword --innodb_recover --skip_flush_tables --mycnf=/etc/mysql/my.cnf --vgname=server1 --lvname=mysql --backuptype=tar

Make sure you fill in the right password, volume group name (server1 here) and the volume name of the volume that contains the MySQL data (the volume is /dev/server1/mysql, therefore the name is mysql).

I everything goes well, you should see lots of output:

root@server1:~# mylvmbackup --user=root --password=yourrootsqlpassword --mycnf=/etc/mysql/my.cnf --vgname=server1 --lvname=mysql --backuptype=tar
20100127 19:16:58 Info: Connecting to database...
20100127 19:16:58 Info: Flushing tables with read lock...
20100127 19:16:58 Info: Taking position record...
20100127 19:16:58 Info: Taking snapshot...
File descriptor 3 left open
Logical volume "mysql_snapshot" created
20100127 19:16:58 Info: Unlocking tables...
20100127 19:16:58 Info: Disconnecting from database...
20100127 19:16:58 Info: Mounting snapshot...
20100127 19:16:59 Info: Copying my.cnf...
20100127 19:16:59 Info: Taking actual backup...
20100127 19:16:59 Info: Creating tar archive /var/cache/mylvmbackup/backup/backup-20100127_191658_mysql.tar.gz
backup/
backup/mydb/
backup/mydb/sys_modules.MYI
backup/mydb/dns_a.frm
backup/mydb/isp_dienste.MYD
backup/mydb/isp_server_ip.frm
backup/mydb/dns_spf.frm
backup/mydb/dns_a.MYI
backup/mydb/isp_fakt_dep.frm
backup/mydb/multidoc_dep.frm
backup/mydb/isp_isp_web_template.MYI
backup/mydb/sys_nodes.MYD
backup/mydb/listtype.MYD
backup/mydb/help_documents.MYD
backup/mydb/help_tickets.MYI
backup/mydb/doctype.frm
backup/mydb/login.MYI
backup/mydb/isp_com.frm
backup/mydb/help_documents.MYI
backup/mydb/isp_dep.MYD
backup/mydb/help_documents.frm
backup/mydb/isp_server.MYD
backup/mydb/isp_fakt_nodes.MYD
backup/mydb/sys_config.MYD
backup/mydb/dns_nodes.MYI
backup/mydb/sys_config.MYI
backup/mydb/isp_monitor.frm
backup/mydb/isp_server_ip.MYI
backup/mydb/isp_isp_datenbank.frm
backup/mydb/dns_secondary.frm
backup/mydb/isp_nodes.MYI
backup/mydb/dns_isp_dns.MYI
backup/mydb/help_nodes.frm
backup/mydb/isp_fakt_nodes.frm
backup/mydb/isp_server.MYI
backup/mydb/isp_isp_domain.frm
backup/mydb/dns_dep.frm
backup/mydb/session.frm
backup/mydb/isp_isp_cron.MYD
backup/mydb/isp_fakt_record.MYI
backup/mydb/isp_monitor.MYI
backup/mydb/isp_fakt_rechnung.MYI
backup/mydb/listtype.MYI
backup/mydb/isp_fakt_rechnung.MYD
backup/mydb/isp_traffic.frm
backup/mydb/isp_fakt_dep.MYI
backup/mydb/user_groups.frm
backup/mydb/isp_fakt_record.frm
backup/mydb/isp_fakt_artikel.MYD
backup/mydb/isp_htaccess.MYD
backup/mydb/sys_nodes.frm
backup/mydb/groups.frm
backup/mydb/login.MYD
backup/mydb/isp_firewall.MYD
backup/mydb/isp_server.frm
backup/mydb/help_tickets.frm
backup/mydb/multidoc_dep.MYD
backup/mydb/dns_nodes.frm
backup/mydb/dns_a.MYD
backup/mydb/sys_config.frm
backup/mydb/dns_isp_dns.frm
backup/mydb/dns_mx.MYI
backup/mydb/isp_isp_web.MYD
backup/mydb/isp_serverstatus.MYI
backup/mydb/isp_serverstatus.MYD
backup/mydb/sys_dep.MYD
backup/mydb/isp_isp_cron.MYI
backup/mydb/session.MYD
backup/mydb/isp_isp_admin.MYD
backup/mydb/dns_ptr.frm
backup/mydb/dns_mx.frm
backup/mydb/isp_isp_domain.MYD
backup/mydb/sys_dep.MYI
backup/mydb/dns_spf.MYD
backup/mydb/user_groups.MYD
backup/mydb/sys_news.frm
backup/mydb/isp_isp_actions.MYI
backup/mydb/doctype.MYD
backup/mydb/multidoc_nodes.frm
backup/mydb/isp_fakt_artikel.frm
backup/mydb/sys_news.MYD
backup/mydb/isp_traffic.MYD
backup/mydb/user_groups.MYI
backup/mydb/sys_news.MYI
backup/mydb/listtype.frm
backup/mydb/del_status.frm
backup/mydb/isp_fakt_nodes.MYI
backup/mydb/isp_isp_kunde.MYD
backup/mydb/isp_dienste.frm
backup/mydb/dns_mx.MYD
backup/mydb/doctype.MYI
backup/mydb/help_tickets.MYD
backup/mydb/dns_secondary.MYI
backup/mydb/dns_ptr.MYD
backup/mydb/isp_isp_reseller.frm
backup/mydb/isp_dienste.MYI
backup/mydb/isp_isp_datenbank.MYD
backup/mydb/isp_isp_actions.MYD
backup/mydb/isp_isp_web.frm
backup/mydb/db.opt
backup/mydb/isp_server_ip.MYD
backup/mydb/multidoc_nodes.MYI
backup/mydb/dns_nodes.MYD
backup/mydb/isp_fakt_rechnung.frm
backup/mydb/isp_isp_reseller.MYI
backup/mydb/isp_nodes.MYD
backup/mydb/isp_htaccess.MYI
backup/mydb/isp_isp_web_template.frm
backup/mydb/isp_isp_domain.MYI
backup/mydb/dns_secondary.MYD
backup/mydb/dns_dep.MYD
backup/mydb/isp_firewall.MYI
backup/mydb/help_nodes.MYI
backup/mydb/isp_isp_admin.frm
backup/mydb/isp_isp_cron.frm
backup/mydb/isp_isp_datenbank.MYI
backup/mydb/isp_traffic_ip.frm
backup/mydb/isp_fakt_dep.MYD
backup/mydb/isp_dep.MYI
backup/mydb/dns_dep.MYI
backup/mydb/isp_isp_reseller.MYD
backup/mydb/dns_isp_dns.MYD
backup/mydb/isp_fakt_artikel.MYI
backup/mydb/multidoc_dep.MYI
backup/mydb/multidoc_nodes.MYD
backup/mydb/del_status.MYD
backup/mydb/groups.MYD
backup/mydb/isp_isp_web_template.MYD
backup/mydb/isp_htaccess.frm
backup/mydb/isp_dep.frm
backup/mydb/isp_isp_web.MYI
backup/mydb/isp_isp_user.frm
backup/mydb/session.MYI
backup/mydb/isp_isp_admin.MYI
backup/mydb/isp_isp_kunde.MYI
backup/mydb/isp_isp_user.MYI
backup/mydb/isp_fakt_record.MYD
backup/mydb/isp_nodes.frm
backup/mydb/groups.MYI
backup/mydb/del_status.MYI
backup/mydb/dns_spf.MYI
backup/mydb/isp_com.MYD
backup/mydb/isp_isp_user.MYD
backup/mydb/dns_cname.frm
backup/mydb/isp_com.MYI
backup/mydb/dns_cname.MYD
backup/mydb/sys_modules.MYD
backup/mydb/isp_traffic_ip.MYI
backup/mydb/help_nodes.MYD
backup/mydb/sys_user.frm
backup/mydb/isp_traffic_ip.MYD
backup/mydb/sys_user.MYD
backup/mydb/sys_modules.frm
backup/mydb/isp_serverstatus.frm
backup/mydb/sys_dep.frm
backup/mydb/isp_firewall.frm
backup/mydb/isp_monitor.MYD
backup/mydb/isp_isp_kunde.frm
backup/mydb/dns_cname.MYI
backup/mydb/isp_isp_actions.frm
backup/mydb/sys_user.MYI
backup/mydb/sys_nodes.MYI
backup/mydb/dns_ptr.MYI
backup/mydb/isp_traffic.MYI
backup/mydb/login.frm
backup/ib_logfile0
backup/mysql_upgrade_info
backup/debian-5.0.flag
backup/mysql/
backup/mysql/host.MYD
backup/mysql/procs_priv.MYD
backup/mysql/time_zone_transition.MYD
backup/mysql/proc.MYI
backup/mysql/time_zone_name.frm
backup/mysql/time_zone_name.MYD
backup/mysql/help_relation.MYI
backup/mysql/user.MYD
backup/mysql/help_category.MYI
backup/mysql/time_zone.frm
backup/mysql/func.MYD
backup/mysql/help_category.MYD
backup/mysql/time_zone_transition.frm
backup/mysql/time_zone_name.MYI
backup/mysql/help_category.frm
backup/mysql/time_zone_leap_second.frm
backup/mysql/time_zone_transition.MYI
backup/mysql/help_relation.MYD
backup/mysql/host.frm
backup/mysql/db.frm
backup/mysql/db.MYI
backup/mysql/columns_priv.frm
backup/mysql/time_zone.MYI
backup/mysql/time_zone_leap_second.MYD
backup/mysql/func.frm
backup/mysql/columns_priv.MYI
backup/mysql/help_topic.MYD
backup/mysql/host.MYI
backup/mysql/proc.frm
backup/mysql/user.MYI
backup/mysql/help_topic.MYI
backup/mysql/help_relation.frm
backup/mysql/tables_priv.frm
backup/mysql/help_keyword.frm
backup/mysql/user.frm
backup/mysql/time_zone_transition_type.MYI
backup/mysql/procs_priv.frm
backup/mysql/help_topic.frm
backup/mysql/procs_priv.MYI
backup/mysql/time_zone_transition_type.MYD
backup/mysql/func.MYI
backup/mysql/proc.MYD
backup/mysql/tables_priv.MYD
backup/mysql/help_keyword.MYI
backup/mysql/help_keyword.MYD
backup/mysql/time_zone_leap_second.MYI
backup/mysql/tables_priv.MYI
backup/mysql/db.MYD
backup/mysql/time_zone_transition_type.frm
backup/mysql/time_zone.MYD
backup/mysql/columns_priv.MYD
backup/lost+found/
backup/ibdata1
backup/ib_logfile1
backup-pos/backup-20100127_191658_mysql.pos
backup-pos/backup-20100127_191658_my.cnf
20100127 19:17:00 Info: DONE
20100127 19:17:00 Info: Cleaning up...
20100127 19:17:00 Info: LVM Usage stats:
20100127 19:17:00 Info: LV VG Attr LSize Origin Snap% Move Log Copy% Convert
20100127 19:17:00 Info: mysql_snapshot server1 swi-a- 5.00G mysql 0.00
Logical volume "mysql_snapshot" successfully removed
root@server1:~#

Afterwards you can find the backup in the /var/cache/mylvmbackup/backup directory (unless you have specified another location):

# ls -l /var/cache/mylvmbackup/backup
root@server1:~# ls -l /var/cache/mylvmbackup/backup
total 248
-rw-r--r-- 1 root root 246847 2010-01-27 19:17 backup-20100127_191658_mysql.tar.gz
root@server1:~#

The tar.gz file contains two directories, backup (with the databases and tables from /var/lib/mysql which you can simply copy back after a database crash - the database should be stopped when you do this) and backup-pos which contains your my.cnf file (a backup of /etc/mysql/my.cnf):

# cd /var/cache/mylvmbackup/backup
tar xvfz backup-20100127_191658_mysql.tar.gz
ls -l
root@server1:/var/cache/mylvmbackup/backup# ls -l
total 256
drwxr-xr-x 5 mysql mysql 4096 2010-01-27 19:10 backup
-rw-r--r-- 1 root root 246847 2010-01-27 19:17 backup-20100127_191658_mysql.tar.gz
drwxr-xr-x 2 root root 4096 2010-01-27 19:24 backup-pos
root@server1:/var/cache/mylvmbackup/backup#

4 Links
mylvmbackup: http://lenz.homelinux.org/mylvmbackup
MySQL: http://www.mysql.com
Debian: http://www.debian.org

How to make Your Ubuntu Linux Enegy Efficient using PowerTop

2010-02-15T17:41:00.000-08:00

How to make Your Ubuntu Linux Enegy Efficient using PowerTop

Since version 2.6.21, the Linux kernel has introduced a feature called tickless. the kernel no longer has a fixed 1000Hz timer tick.

This will give a dramatic power savings because the CPU stays in low power mode for longer periods of time during system idle.

A Nice handy tool, PowerTop has been created for reducing the Power Usage of Linux.

This application will help to find the software components that are preventing optimal usage of your hardware and give proper suggestions for both hardware and software configurations to reduce power consumption of your system.

So Now Your Ubuntu is energy Efficient.It is very useful for Laptop Users.

How To Install PowerTop in Ubuntu

Open a terminal and type the following

$ sudo apt-get install powertop

Or You can use Synaptic Package manager and select package powertop.

15 Remote Desktop Solutions for Linux

2010-02-15T17:32:00.000-08:00

15 Remote Desktop Solutions for Linux.

There are a wide range of remote desktop applications that are available that can be used to connect to Windows environment but there aren’t too many that can be used to remote desktop from Linux to Linux or Windows to Linux.

With this I mean, getting entire desktop of remote Linux environment on your local workstation.

Most people who are used to a Unix-style environment know that a machine can be reached over the network at the shell level using utilities like telnet or ssh.

And some people realize that X Windows output can be redirected back to the client workstation. But many people don’t realize that it is easy to use an entire desktop over the network. There are a several of open source applications that can be used to achieve this.

1) VNC (Virtual Network Computing)
is a remote display system which allows the user to view the desktop of a remote machine anywhere on the internet. It can also be directed through SSH for security.

Basically you install VNC server on the server and install client on your local PC. Setup is extremely easy and server is very stable.

On client side, you can set the resolution and connect to IP of VNC server. It can be a bit slow compared to Windows remote desktop and also has the tendency to take more time refreshing over low-bandwidth links.

All in all VNC is an amazing piece of free software that gets the job done.

There is RealVNC , TightVNC and UltraVNC. Each has it’s advantages and disadvantages. Most popular one is RealVNC but if you’re upto it, experiment with all three and choose the one that works for you best.

By default, communication between client and server is in clear text on port 5900. However, you can easily route all traffic via SSH tunnel.

Here is a quick way of setting it up if you have access to command line shell:

# ssh -ND 5900 @remote.server.com

When you get prompted, enter your password. Pop open VNC client and connect to ‘localhost’. This’ll route your connection to VNC server on remote machine.

You can download VNC from:

2) Then there is FreeNX.
FreeNX is a system that allows you to access your desktop from another machine over the internet. You can use this to login graphically to your desktop from a remote location.

One example of its use would be to have a FreeNX server set up on your home computer, and graphically logging in to the home computer from your work computer, using a FreeNX client.

It provides near local speed application responsiveness over high latency, low bandwidth links.

FreeNX can be configured to run via SSH without any tunneling. It binds to your existing SSH install. Instead of guiding you through the installation of FreeNX in this article, you can visit the following URLs that’ll guide you through the installation on Ubuntu:

3) The third free application is 2X Terminal Server for Linux.
2X TerminalServer for Linux is an Open Source project, licensed under the GPL and is free of charge.

As far as performance goes, NoMachine’s technology is on par with Windows’ own Remote Desktop Protocol (RDP) suite, better than VNC.

Both X2 and FreeNX is based on NoMachine technology.

Here are some quick links if you’re interested in using this software:

Download at http://www.2x.com/terminalserver/download.htm
Forum is at http://www.2x.com/forums

4) Then there is is XDMCP.
The X Display Manager Control Protocol uses UDP port 177.

Compared to the list above, it’s not as easy to setup for remote desktop but it’s the original way of doing this on Linux.

You can get setup instructions and other tips in the following URL:

http://www.tldp.org/HOWTO/XDMCP-HOWTO/intro.html

5) CygwinX.
A complete Linux emulation on Windows. You’ll find every tool and app that you have on Linux on Cygwin.

Get it from http://www.cygwin.com

6) XRDP.
RDP server that runs on Linux, thus allowing you to use Windows Remote Desktop Client or rdesktop to connect.

Get it from http://sourceforge.net/projects/xrdp/

7) x2vnc
great little utility that allows you to tie a linux and windows (or anything that can run the vncserver) together with a single keyboard/mouse, avoiding the need for a switcher box.

Mousing cross screens transparently switches between machines, and cut and paste works.

Get it from http://fredrik.hubbe.net/x2vnc.html

8 ) Xming
It’s a great and lightweight implementation of X11 for Windows that allows you to connect to a Linux box.

You can read about it at http://freedesktop.org/wiki/Xming

9) KDE Desktop Sharing (formerly krfb)
Part of KDE since version 3.1. It is located in the kdenetwork package. If your distribution splits the KDE applications into separate packets, you may find the client as ‘krdc’ and the server as ‘krfb’.

Also uses VNC technology.

10) X-Win32
Top rated PC X server solutions for Windows PCs connecting to remote Unix and Linux host systems.

Works well over SSH.

Get it from http://www.starnet.com/products/xwin32/

11) Single Click UltraVNC
In case you would like to remote control without any software installed on the target computer you need UltraVNC SC.

The user on the to be controlled computer needs to simply click on a web page and remote controlling begins.

Get it from here http://ultravnc.sourceforge.net/addons/singleclick.html

12) CrossLoop
CrossLoop is a FREE secure screen sharing utility designed for people of all technical skill levels.

CrossLoop extends the boundaries of VNC’s traditional screen sharing by enabling non-technical users to get connected from anywhere on the Internet in seconds without changing any firewall or router settings.

Get it from http://www.crossloop.com/

13) Thinstation
Although not a remote desktop app but worth mentioning here. Thin client linux distro for terminals using std. x86 hw.

It can boot from network, pxe, syslinux,loadlin, CD, floppy or flash-disk and connect to servers using VNC, RDP, XDM, SSH and etc.

Get it from http://sourceforge.net/projects/thinstation

14) rdesktop
an open source client for Windows NT Terminal Server and Windows 2000/2003 Terminal Services, capable of natively speaking Remote Desktop Protocol (RDP) in order to present the user’s NT desktop.

rdesktop currently runs on most UNIX based platforms with the X Window System, and other ports should be fairly straightforward.

Download from: http://www.rdesktop.org/

While you’re at it, get grdesktop from (http://www.nongnu.org/grdesktop/). It is a GNOME frontend, for rdesktop.

It can save several connections (including their options), and browse the network for available terminal servers.

15) ssh -X
You can check out this great article written by a slashdot user sometime ago.

Read it here http://slashdot.org/~Trolling4Dollars/journal/69740

Windows to Mac / Mac to Windows

1) RDP Client for Mac
allows you to connect to a Windows-based computer and work with programs and files on that computer from your Macintosh computer.

Download it here

2) OSXVnc
Vine Server is a full featured VNC server for Mac OS X providing remote access to the GUI, keyboard and mouse using Vine Viewer or any other VNC client.

Download it from http://www.redstonesoftware.com/products/vine/server/vineosx/index.html

3) Chicken of the VNC
A VNC client allows one to display and interact with a remote computer screen. In other words, you can use Chicken of the VNC to interact with a remote computer as though it’s right next to you.

Download it from http://sourceforge.net/projects/cotvnc/

Unfortunately I was not able to find too many available to connect to Mac from Windows other than VNC.

I think Windows need to support RDP into Mac. Many people would benefit from this.

If I am missing anything from the list, please let me know.

How to: Extract files from ISO CD images in Linux

2010-01-31T04:53:00.000-08:00

Under many situations you may need to get a single file/many files from Linux ISO image.

You can mount ISO images via the loop device. You need to use mount command. First login as a root user:

Extract File(s) Under Linux OS

Let us assume that your ISO image name is disk1.iso.

Step # 1: First you need to create a directory /mnt/iso

# mkdir /mnt/iso
# mount -o loop disk1.iso /mnt/iso

Step # 3: Extract file

Now you can easily copy file called file.txt from iso disk image to /tmp directory :

# cd /mnt/iso
# cp file.txt /tmp

Step # 4: Copy foo.rpm from ISO disk image:

# cd /mnt/iso/RedHat/RPMS
# cp foo.rpm /tmp

Extract File(s) Under Windows XP or Vista Os

Windows do not have in built capability as provided by Linux to extract file. Luckly many third party software exist my favorite is Winimage http://www.winimage.com/. Download trial version (I’m sure you will love to registered this tiny utility later):

1) Install Winimage software

2) Just double click on Linux ISO file

3) Select the desired file and hit CTRL + X (or from Image menu select extract)

For more information read man pages:

man cp
man mv
man rpm
man mount
man mkdir

How To Change XSplash Themes in Ubuntu 9.10

2010-01-15T04:50:00.000-08:00

With every new release of Ubuntu, there s a new XSplash theme that comes in. Today we show you how to change it and also show you some cool themes you might want to add to your machine.
XSplash
XSplash is a software project in the Ubuntu community that uses the X Window System to replace the scrolling-text screens that appear while booting a Linux-based computer with a graphical splash screen.
Previous versions of Ubuntu, (before Karmic Koala) used USplash which now is history. The default XSplash screen in Karmic Koala looks something like the one below& which is actually not too bad.

However, you don t have to live with the default XSplash if you don t like it. You can always change your XSplash screen to make it look better, and customize it to your Ubuntu overall theme. The following is the XSplash screen that I am currently using.

Change Themes
In order to change the XSplash screen in Ubuntu Karmic Koala follow these steps:
1. Open nautilus as root by typing gksu nautilus at the run prompt (Alt + F2).
2. Download the XSplash archive that you want to use and move the content of the archive to

/usr/share/images/xsplash folder.

Note: Make sure that you take the back up of your current XSplash, by copying the default files to some safe location before copying the new XSplash theme files.
Once you have installed the new XSplash theme you can check how it looks by typing the following command at the terminal.

sudo xsplash

Cool XSplash Themes
Now that you know how to change it, let s take a look at some of the different themes. Here is a list of cool themes we ve found.
Fusion-GX-v00

Download Fusion-GX-v00

Xsplash Crunchy Branch

Download Xsplash Crunchy Branch
Ubuntu clean xsplash

Download Ubuntu clean xsplash

Mesh Grill

Download Mesh Grill
XSplash-CF-GX

Download XSplash-CF-GX

PackoXsplash HD

Download PackoXsplash HD

Xsplash (for netbook)

Download Xsplash (for netbook)
Xsplash-Engranes-GX-01a

Download Xsplash-Engranes-GX-01a

Chromiu-GX

Download Chromiu-GX
This will allow you to customize your Ubuntu installation a bit more& especially if you match it with your overall unique Ubuntu theme. Have Fun!

Original post by : HowToGeek

10 Useful Linux Commands

2010-01-12T18:18:00.000-08:00

10 Useful Linux Commands

Here's a list of 10 commands which may come handy when using the command line in Linux:

Search for all files modified in the last N days containing a specific text in their name

find DIR -mtime -N -name "*TEXT*"

For example:

find ~ -mtime -5 -name "*log*"

Will display all the files modified in the past 5 days which include the text 'log' in their filename.

Determine which processes use the most memory

ps aux | sort -nk 4 | tail

Will show the first 10 processes which use the most memory, using ascendant sorting. Alternately:

ps aux | sort -nrk 4 | head

Will show the first 10 processes using most memory, using descendent sorting.

Output of ps aux | sort -nrk 4 | head

Display the username which is currently logged in

whoami

Show date using format modifiers

date +"%H:%M:%S"

Will output time in format HOUR:MINUTE:SECOND. You can use any format specifiers explained in the man page. The double quotes are required in case you need to use spaces.

Showing date in format month, day year

Show info about a specific user

finger $USER

Output of finger $USER

Show disk usage separately for each partition

df -h

The -h switch will tell df to show human-readable sizes (KB, MB and GB when it is the case)

df -B 1K

Will show sizes in kilobytes.

Show which modules are loaded

lsmod

Add or remove a module to/from the Linux kernel

Insert a module:

modprobe MODULE

Remove a module:

modprobe -r MODULE

Search for a file using locate

locate FILENAME

Will search the locate database (created with updatedb) for any path or file which contains FILENAME.

Change the encoding of a text file

iconv -f INITIAL_ENCODING -t DESIRED_ENCODING filename

For example:

iconv -f ISO-8859-16 -t UTF-8 myfile.txt

Will change the encoding of myfile.txt from ISO-8859-16 (Romanian) to UTF-8.

Top Ten Things I Miss in Windows

2010-01-12T18:00:00.000-08:00

There is an old saying that goes "you can't miss what you never had" meaning that for those who have never had something of these things they will have no idea what they are missing out on.

Typically I use Ubuntu or some Linux flavor as my operating system for every day tasks, however as most techs know using Windows is unavoidable at times. (Whether it be because I am fixing someone else's machine, at work/school, or queuing up some Netflix watch instantly on my home system)

That being said the following are the top ten features/programs I find myself grumbling about/missing the most when I am working on the Windows platform:

10.) Klipper/Copy & Paste Manager - I use this one alot when I am either coding or writing a research paper for school.

More often than not I find I have copied something new only to discover I need to paste a link or block of code again from two copies back.

Having a tray icon where I can recall the last ten copies or so is mighty useful.

9.) Desktop Notifications - This is something that was first largely introduced in Ubuntu 9.04 and something I quickly grew accustomed to having.

Basically it is a small message (notification) the pops up in the upper right hand corner of your screen for a few moments when something happens in one of your programs (a torrent finishes, you get a new instant message, ect.) or you adjust the volume/brightness settings on your system.

8.) "Always on Top" Window Option - This is something I find useful when I am instant messaging while typing a paper, surfing the net, or watching a movie on my computer.

Essentially what it does is make sure that the window you have this option toggled on is always at the top of your viewing regardless of what program you have selected/are working in.

It is useful because it allows me to read instant messages with out having to click out of something else that I am working on.

7.) Multiple Work Spaces - When I get to really heavy multitasking on a system having multiple different desktops to assign applications to is a god send.

It allows for better organization of the different things I am working on and keeps me moving at a faster pace.

6.) Scrolling in the Window/Application the Cursor is Over - This one again is mostly applicable when some heavy multitasking is going on (but hey - its almost 2010, who isn't always doing at least three things at once right?).

Basically in Ubuntu/Gnome desktop when I use the scroll on my mouse (whether it is the multi-touch on my track pad or the scroll wheel on my USB mouse) it will scroll in what ever program/window my mouse is currently over instead of only scrolling in what ever application I have selected.

5.) Gnome-Do - Most anyone who uses the computer in their everyday work will tell you that less mouse clicks means faster speed and thus (typically) more productivity.

Gnome-Do is a program that allows you to cut down on mouse clicks (so long as you know what program you are looking to load).

The jist of what it does is this: you assign a series of hot keys to call up the search bar (personally I use control+alt+space) and then you start typing in the name of an application or folder you want to open and it will start searching for it - once the correct thing is displayed all you need to do is tap enter to load it up.

The best part is that it remembers which programs you use most often. Meaning that most times you only need to type the first letter or two of a commonly used application for it to find the one you are looking for.

4.) Tabbed File/Folder Viewing - Internet Explorer finally got tabs! Why can't the default Window's explorer for viewing files/folders join it in the world of twenty-first century computing?

Tabs are very useful and are a much cleaner option when sorting through files as opposed to having several windows open on your screen.

3.) Removable Media Should Not Have a Driver Letter - The system Windows uses for assigning letters to storage devices was clearly invented before flash drives existed and I feel it works very poorly for handling such devices.

It is confusing to new computer users that their removable media appears as a different drive letter on most every machine (and even on the same machine sometimes if you have multiple drives attached).

A better solution is something like Gnome/KDE/OSX do: have the drive appear as an icon on the desktop and have the name of drive displayed not the drive letter (its fine if the letter still exists - I under stand the media needs a mount point, just it adds confusion displaying this letter instead of the drive name)

2.) Hidden Files that are Easy/Make Sense - I love how Linux handles hidden files. You simply prefix your file name with a "." and the poof its gone unless you have your file browser set to view hidden folders.

I think it is goofy to have it setup as a togglbe option within the file's settings. Beyond that Windows has "hidden" files and "hidden" files to further confuse things.

1.) System Updates that Install/Configure Once - I've done more than my fair share of Windows installs and the update process it goes through each time irks me beyond belief.

The system downloads and "installs" the updates, then it needs to restart. Upon shutting down it "installs" the updates again and then proceeds to "configure" them.

Then once it comes back online it "installs" and "configures" the updates one last time. Why? On Ubuntu the only update I need to restart for is a kernel update - even then most times I stick with my older kernel most times unless I have a specific reason for changing to the new one.

0.) Wobby Windows - This one doesn't effect productivity or use-ability like the other ten, but I must say after using mostly Ubuntu for the last year and a half not having the windows wobble when I drag them around the screen is a huge kill joy.

I'm aware that a few of my above mentioned things can be added to Windows through third party software- however like I said most times when I am using Windows it is at work, school, or for a few moments on a friends system. Meaning I'm not about to go installing extra things on them/changing configurations.

Anyone else have some other key things/features they miss when using the Windows platform when coming from else where?

Three ways to securely access remote internal networks and work from home

2010-01-12T17:54:00.000-08:00

Three ways to securely access remote internal networks and work from home

Remote access to a computer and internal network’s secured resources - all of it in a simple way that’s following well-known security’s best practices?

Sounds impossible, but it’s not. How to achieve it explains Bartosz Feński aka fEnIo.

A computer network with a tight security should be separated from the outside world as much, as it’s possible.

It’s often the case. Even if there is a over a dozen of devices(PCs), that play different parts assigned to them in terms of company’s infrastructure, usually there is one that separates them from others, a firewall and a router.

On the assumption that the company’s policy is not too strict we often have an free access to this kind of devices.

It can be various internal services, databases, servers of whatever is necessary to run a current company.

What if, after work, when we are home safe and sound, we still need to connect to one of those servers that are not accessible outside the internal network.

I’ll describe few ways to do it.

SSH ProxyCommand
The simplest and, as far as I reckon, the most often case is when just behind firewall there is a 2nd server accessible by SSH, but only for LAN users.

It’s similar to the situation, where router does NAT, and server’s addresses behind him are from private address’ classes.

Therefore, If we want to log in, we need to log in to the firewall first.

Sounds familiar ? How many times have you actually tried to do the following:

laptop$ ssh router
[password1]
router$ ssh server
[password2]
server$

I’ve done it millions of times, and if someone does something often enough there is a chance that it would be so infuriating that eventually someone will try to automate it. SSH share the same story.

Let’s make an configuration file on a laptop ~/.ssh/config:

Host server
ProxyCommand ssh router nc %h %p 2> /dev/null

For this configuration to work a program called netcat is necessary, but most of the distributions have it in high-priority packages so it’s often already installed, so… How does the server connection looks like ?

laptop$ ssh server
[password1]
[password2]
server$

Let’s generate a key so we won’t be bothered about all the passwords.

laptop$ ssh-keygen
laptop$ ssh-copy-id router
laptop$ ssh-copy-id server

laptop$ ssh server
server$

The coolest thing about it all is the fact, that along with the possibility of logging in to a device that is not public-accessible, we also get the full set of SSH features.

There is no problem in using scp, sshfs, forwarding Xs or to set a tunnel to other device through a server.

But what if…

laptop -> router1 -> router2 -> ... -> routerN -> server

There are no barriers to add several devices to ~/.ssh/config and automate the whole login process even if u need to log in to few middle devices before logging in to the right one. You just need to define the right proxy command.

SSH SOCKS
SSH problem is solved, but what if the service we try to get to is, for example, a WWW server? We can use text browsers from the device we logged in, but it’s not really elegant or convenient.

We can use,mentioned earlier, port forwarding, that along with automatic login to different devices is a pretty flexible solution, but we need to remember to add certain SSH commands to every service or setting it all up in ~/.ssh/config)….
… but SSH function SOCKS saves the day:

laptop$ ssh -D 8080 router
[password1]
router$

If we generated a key, then we don’t need to give a password. We need to set up localhost as a SOCKS server and port 8080 in our browser.

All connections will be tunneled to the router and visible for the WWW server as if they were initiated from this device.

Not every applications let’s you use SOCKS server though, but there is a cure. It’s called tsocks. It’s a simple program, that with the help of LD_PRELOAD variable, makes applications use the alternative versions of the connect(), sendto(), socket() functions.

Thanks to that the applications can use middle servers almost without any dedicated configuration, unconsciously if we may use this term in reference to binary beings.

The configuration file should look as follows:

server = 127.0.0.1
server_type = 5
server_port = 8080

Now the applications, we’d like to “deceive” should be run:

laptop$ tsocks application_without_socks_support

As I’ve just presented, with SSH and a simple program we can quite easily organize our work environment and bypass limitations caused by a firewall. We can’t solve all our problems though. Let’s take our old FTP for example.

It needs 2 ports to communicate, so it can’t be deceived in the way shown above. Moreover, if there is 40 services run on 30 devices behind firewall SSH configuration will be exceptionally complex and hard to maintain.

Perfect would be a solution, in which our laptop with a certain address’ class simply connects to through a channel to the targeted devices in a way, that the device knows the connection came from a secured and trusted network.

OpenVPN
OpenVPN solves the problem. To the contrary to SSH-based solutions, that works on 7th layer (application), OpenVPN works on 3rd (network)or even 2nd (transport) layer so it’s entirely transparent for the software.

Moreover, it comes with authentication and encryption, so we don’t loose anything comparing to SSH.

Although since version 4.3 OpenSSH makes 2/3 layer tunneling possible,
but its configuration stands next to impossible.

OpenVPN allows making advanced configurations and, for instance, setting up a secured connection between several corporate branches.

I’ll limit the example and only show how to gain access in the case described at the beginning of this article.

Laptop will be a client and a VPN server will be configured on a router.

I assume, that openvpn package is installed on the laptop and the router. Let’s generate a key (that will be used to encrypt and authenticate the transmission) on the router.

router$ openvpn --genkey --secret /etc/openvpn/static.key

And a configuration file /etc/openvpn/server.conf:

dev tun
ifconfig 10.8.0.1 10.8.0.2
secret static.key

10.8.x class’ addresses will be used to set up a tunnel. You are free to choose your own addresses.

One thing left is to run the server:

router$ sudo /etc/init.d/openvpn start

We should get one more interface

tun0      Link encap:UNSPEC
HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet addr:10.8.0.1  P-t-P:10.8.0.2  Mask:255.255.255.255
UP POINTOPOINT RUNNING NOARP MULTICAST  MTU:1500  Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

Moreover we need to unlock the 1194 port in firewall setup.
We copy generated static.key on the laptop and we create client configuration file /etc/openvpn/client.conf:

remote routers_address
dev tun
ifconfig 10.8.0.2 10.8.0.1
secret static.key
route 192.168.0.0 255.255.255.0

Now we switch routers_address to its actual address. Route option will make a new record in routing table visible and from now all transfer is directed to the set up tunnel.

Last but not least thing we have to do is to run VPN on the laptop:

laptop$ sudo /etc/init.d/openvpn start

Let’s look at the routing table:

10.8.0.1    0.0.0.0    255.255.255.255 UH  0    0    0 tun0
192.168.0.0 10.8.0.1   255.255.255.0   UG  0    0    0 tun0

That’s the way to set up the simplest configuration. Of course, as everything, It has its flaws.

For example, everyone who has the key can access our network – sometimes though the key may fall into the wrong hands.

OpenVPN has its own, more sophisticated authentication methods – simply get the generated key password-protected, but its security is far beyond this article framework.

Linux Live USB Creator

2010-01-11T14:04:00.000-08:00

LiLi USB Creator is a free software for Windows that allows you to create a bootable Live USB key with a Linux on it.
This software also offers an exclusive option of automatic virtualization to directly run Linux in Windows without any configuration nor installation.

create bootable Live USB of Ubuntu, Fedora, Debian, Damn Small Linux, Puppy Linux and many others !
enable persistency of your data
launch Linux directly in Windows with a special Portable VirtualBox
hide created files on the key

Anybody can use LiLi USB Creator. It's really easy to use and you don't have to be a computer geek !

DOWNLAD

Use the link below to follow a step by step procedure on how to use LiLi :
http://www.linuxliveusb.com/en/how-to.html

Color man pages

2010-01-10T08:36:00.000-08:00

A nice feature of less which enables you to set termcap colors by environment variables.

Just use

export LESS_TERMCAP_mb=$'\E[01;31m'
export LESS_TERMCAP_md=$'\E[01;31m'
export LESS_TERMCAP_me=$'\E[0m'
export LESS_TERMCAP_se=$'\E[0m'
export LESS_TERMCAP_so=$'\E[01;44;33m'
export LESS_TERMCAP_ue=$'\E[0m'
export LESS_TERMCAP_us=$'\E[01;32m'

in your ~/.$SHELLrc to get this effect.

Thanks to : http://nion.modprobe.de/blog/archives/572-less-colors-for-man-pages.html

Saving Bandwidth and Speeding Up Your Site With GZIP and Browser Caching

2009-12-31T05:31:00.000-08:00

There are a couple of easy adjustments you can make to your web server in order to decrease page loading times, save bandwidth, and reduce load on the server. All you have to do is add a couple of code snippets to either your Apache server configuration file (httpd.conf or apache2.conf) or an .htaccess file.
Note that these require that your server have certain modules installed for this to work. You will need either mod_deflate or mod_gzip for GZIP compression and mod_expires for the browser caching trick.

Enable Browser Caching

When a web browser loads a page, it checks each item it requests (JavaScript, CSS, images, etc) against its local cache. If an item, say the stylesheet, hasn’t expired yet, then it will load the local copy instead of requesting a new one. Now if you were to instruct your server to set the expiration time for images, CSS, and JavaScript files to one month from the present, users viewing multiple pages of your site (even across multiple days) won’t tax your resources as much, as they will use the copies of your stylesheets and images that have already been downloaded.
Insert this into your .htaccess file or Apache config, restarting Apache if you chose the latter:

 ExpiresActive On

 ExpiresDefault "access plus 1 month"

Now any file with an extension of ICO, JPG, JPEG, PNG, GIF, JS, CSS, SWF will be set to expire one month from the time the browser caches it.

GZIP Compression

Now wouldn’t it be nice if you could cut down on the size of the file? There’s no point in doing it for images (which are already compressed) but you can greatly reduce the size of text-based files (HTML, JavaScript, CSS) by having the server compress them before sending them out.
Add this to your .htaccess or Apache config (restarting Apache if you chose the latter) as before:

SetOutputFilter DEFLATE

SetEnvIfNoCase Request_URI \.(?:gif|jpe?g|png)$ \

 no-gzip dont-vary

SetEnvIfNoCase Request_URI \

 \.(?:exe|t?gz|zip|bz2|sit|rar)$ \

 no-gzip dont-vary

SetEnvIfNoCase Request_URI \.pdf$ no-gzip dont-vary

BrowserMatch ^Mozilla/4 gzip-only-text/html

BrowserMatch ^Mozilla/4\.0[678] no-gzip

BrowserMatch \bMSIE !no-gzip !gzip-only-text/html

This beast does several things. The first directive tells mod_deflate to get to work. The next several lines determine how mod_deflate will work. It will not affect GIF, JPG, PNG images or already-compressed archive files (e.g. ZIP or RAR), as there is no real benefit in doing so. The final three “BrowserMatch” lines deal with Internet Explorer’s funkiness.

Is it Working?

If you have Firebug and the handy Google Page Speed extension installed, you can run a quick test to make sure everything is working right. There should be two lines mentioning “Leverage browser caching” and “Enable gzip compression.” They should be checked-off instead of having a red icon.

How to enable mod_deflate globally in cPanel/WHM

2009-12-31T03:09:00.000-08:00

How to enable mod_deflate globally in cPanel/WHM

This will be a quick one folks. The Apache module mod_deflate helps in reducing the size of the information sent to a user, by compressing things prior. It seems to work very well. To test if your site already has mod_deflate installed and working, you can go here:

http://www.whatsmyip.org/http_compression/

To enable mod_deflate on your WHM / cPanel server, make sure you run EasyApache through WHM, and select to install mod_deflate. Once done, you’ll notice that it is not active globally. In your cPanel control panel for your domain, you should notice that under “Software / Services” an icon called “Optimize Website” is now there.
If however, you wish enable it globally, so that all websites on your server can benifit from this, you need to venture back into WHM, and this time go to:

Services Configuration >> Apache Configuration >> Include Editor >> Post VirtualHost Include, and select All Versions

Now, paste the following into this file, and hit Update:

SetOutputFilter DEFLATE

# Netscape 4.x has some problems…
BrowserMatch ^Mozilla/4 gzip-only-text/html

# Netscape 4.06-4.08 have some more problems
BrowserMatch ^Mozilla/4\.0[678] no-gzip

# MSIE masquerades as Netscape, but it is fine
# BrowserMatch \bMSIE !no-gzip !gzip-only-text/html

# NOTE: Due to a bug in mod_setenvif up to Apache 2.0.48
# the above regex won’t work. You can use the following
# workaround to get the desired effect:
BrowserMatch \bMSI[E] !no-gzip !gzip-only-text/html

# Don’t compress images
SetEnvIfNoCase Request_URI .(?:gif|jpe?g|png)$ no-gzip dont-vary

# Make sure proxies don’t deliver the wrong content
Header append Vary User-Agent env=!dont-vary

That’s it, now, go back to the site I gave you at the start, load up your website, and verify that compression is now functioning.

For you command line users, you can achieve this my running the easy apache command line build (/scripts/easyapache), and select to include mod_deflate. Once that is done, you can edit the “/usr/local/apache/conf/includes/post_virtualhost_2.conf” file, and paste the above code into it to achieve the same results. Remember to restart apache once you’ve edited the file.

Configure mod deflate for Apache 2.2.x

2009-12-31T03:04:00.000-08:00

Mod Deflate comes built into Apache, but is not enabled by default. This tutorial will explain the simplest way of enabling it and setting which mime times to compress. Mod Deflate will increase your server load, but decreases the amount of time that clients are connected and can usually reduce the page size by 60 to 80 percent.

Loading Mod Deflate

First make sure that you are loading mod_deflate.so, this line should be at the top of your httpd.conf file and is usually loaded by default.

LoadModule deflate_module libexec/apache22/mod_deflate.so

Mod Deflate Settings

Second create a new config file to keep the deflate options in.

# ee /usr/local/etc/apache22/Include/mod_deflate.conf

This file will be included in the main httpd.conf file. Inside the file add the following:

AddOutputFilterByType DEFLATE text/html text/plain
#Highest 9 - Lowest 1
DeflateCompressionLevel 9

#Optional
#Skip browsers with known problems
BrowserMatch ^Mozilla/4 gzip-only-text/html
BrowserMatch ^Mozilla/4\.0[678] no-gzip
BrowserMatch \bMSIE !no-gzip !gzip-only-text/html

#Optional
#Logging
DeflateFilterNote ratio
LogFormat '"%r" %b (%{ratio}n) "%{User-agent}i"' deflate
CustomLog /usr/local/www/logs/deflate_log deflate

The compression level can be adjusted. 9 gives the highest compression, the smallest file sizes, and also uses the most CPU cycles.
Once you have this config file added restart apache.

# apachectl graceful

Testing Mod Deflate

To test your compression you can compare the file size by looking at the apache logs or a tool use as port80 tools.

Compressing additional types

You can compression additional mime types coming out of your server by adding them to the AddOutputFilterByType list in the mod_deflate.conf file. Some you might want to add are text/css, application/x-javascript, text/xml, and any others that are would benefit from being compressed.

How To Install Gnome 3 Shell in Ubuntu Karmic Koala

2009-12-31T02:19:00.000-08:00

If you want to experience it first hand, we will tell you what you how to do it in this article. Just to start off here is a screenshot of the Gnome 3 Shell:

Note: Gnome-Shell is still in the development stage and there is always the possibility of something breaking.

1. Open terminal and run the command below to install the Gnome Shell

sudo apt-get install gnome-shell

2. After the installaton is done you can start it using the command below in terminal

gnome-shell --replace

3. If you have intel graphics and get just a blank screen after the above command run the command given below before the command in step 2.

export GNOME_SHELL_DISABLE_TFP=1

K9Copy Ubuntu

2009-12-31T01:58:00.000-08:00

K9Copy

K9Copy is a program that allows you to copy DVDs (and other audio-video media) in Linux. It has the following features:

Video compression (to make the video fit on a 4.7GB recordable DVD, or any size desired)
DVD burning
Creation of ISO images
Choice of audio and subtitle tracks to be copied
Title preview (video only)
Preservation of original menus

Homepage: http://k9copy.sourceforge.net/

Warning: As always, check the relevant copyright laws for your country regarding the backup of any copyright-protected DVDs and other media.

Installing K9Copy from the Repositories

K9Copy requires the multiverse repository - enable this in Software Sources

Search for the package k9copy in Synaptic, Adept, KPackageKit, or other package manager.

Or, to install via terminal:

```
sudo apt-get install k9copy
```

Activate Support for Encrypted DVDs

Encrypted DVD playback requires the installation of libdvdcss2 from the Medibuntu repositories. libdvdcss will need to be enabled for K9Copy to have full functionality.

* You can install libdvdcss2 from a command line terminal as a 64-bit .deb package without installing the Medibuntu repositories:

wget -c http://packages.medibuntu.org/pool/free/libd/libdvdcss/libdvdcss2_1.2.10-0.2medibuntu1_amd64.deb
sudo dpkg -i libdvdcss2_1.2.10-0.2medibuntu1_amd64.deb

or a 32-bit .deb package:

wget -c http://packages.medibuntu.org/pool/free/libd/libdvdcss/libdvdcss2_1.2.10-0.2medibuntu1_i386.deb
sudo dpkg -i libdvdcss2_1.2.10-0.2medibuntu1_i386.deb

See RestrictedFormats for more information on playing encrypted DVDs and other non-free media.

Using K9Copy

K9Copy should now appear under Menu -> Applications -> Sound & Video in Gnome (Ubuntu) or Menu -> Multimedia in KDE (Kubuntu) or XFCE (Xubuntu). You can also start K9Copy from a command-line terminal (or by pressing Alt + F2):

k9copy

Quickstart guide

K9Copy works in both KDE and Gnome. To copy a normal DVD and shrink it down to 4.7Gb, set the input device to your DVD and output as ISO image. Open the video using the 'folder' icon at top left. Under the MPEG4 Encoding tab, select Video codec as copy. Ticking the 2 pass box will give a higher quality copy. Set file size to say, 4700MB (note that there have been reports e.g. that this value is sometimes slightly exceeded).

Select the title(s) of interest. Then press the circular to DVD icon. It will ask for a location to create the iso copy. Note that when it starts, it misleadingly says 'Burning DVD' - what its actually doing is creating the iso copy on the hard drive - rest assured the DVD is NOT being overwritten! A dvd can then be created from the resulting iso file with another program eg. Nautilus (right click on the iso) or K3b. Although k9copy can also burn the iso (or a DVD structure), using a separate program has been reported to be more reliable.

Tip: To preview the titles, highlight the title/chapter of interest and click on the 'movie camera' icon - only THEN can you use the stop/play buttons in the preview window.

If you wish to change the Menu structure (reauthor the DVD), you can use qdvdauthor.

*DVD::Rip is another full-featured solution for DVD ripping in Linux.

*DVDShrink is a Windows-based program that must be run in Wine in Linux.

Using Rsync

2009-12-31T01:29:00.000-08:00

What is rsync?

Rysnc helps you transfer data from one location to another in an efficient manner. It is one of those tools that you learn to use and wonder how you lived without it. Rsync is the de facto standard in backup solutions because of its flexibility and power.
Rsync checks each file and transfers only what has changed. What does this mean exactly? Rsync will actually look and see what in the file has changed and upload only the part of the file that has changed. Unlike ftp and other transfer solutions rsync doesn’t simply re-upload the entire file.
The difference in the files are then compressed (an optionally encrypted through ssh) then sent so the transfer uses the minimal amount of bandwidth. Rsync is often used by Amazon S3 users as they must pay for bandwidth. When you are paying bandwidth bit by bit you can’t afford anything but rsync.

Rsync is Efficient but What Else Can it Do?

As you can probably tell by the name rsync is really good at syncing files across a network. If a file has changed it can detect the change and transfer only that change. This makes rsync a perfect candidate for doing incremental backups or mirroring a website.
For example to mirror one folder to another you could do:

rsync –av /path/to/source /home/nixtutor/rsync/daily

You can also use the same technique to sync from one computer to another:

rsync –av /path/to/source user@nixutor.com:/home/nixtutor/rsync/daily

By default this will only upload new files and changes but not delete or remove files that no longer exist. To do this you can add the –delete flag. This is rsync’s way of protecting yourself from mirroring a blank directory.

rsync –av –delete /path/to/source user@nixutor.com:/home/nixtutor/rsync/daily

Want to Sync Specific Files?

In this example we only sync .iso files.

rsync -zrv –include=”*.iso” host:/home/nixtutor /home/

Things to Keep in Mind

Rsync is powerful but unforgiving
Rsync follows the unix methodology, do one thing and do it well. Thus it doesn’t provide encryption only efficient file transferring. Run rsync through SSH if you need encryption.
Rsync will not delete files that have been removed unless you supply the –delete flag.
Windows doesn’t keep file modification times to better than two seconds. Use the –modify-window=2 option to get around this when syncing to Windows file shares.

Most backup senarios can be done with rsync and cron.

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