Augur's Ramblings

Notice...

2010-02-02T14:09:00.002-05:00

I may not be posting anything for quite some time. Google has decided to discontinue the service which this website utilizes. You'll still be able to view existing content but I won't be able to add new content. Hopefully I'll have time to move everything to a new system some day soon...

PHP 102: Installing Eclipse IDE for PHP on Ubuntu 9.04

2010-01-10T01:20:00.003-05:00

PHP 102: A Portable Apache+PHP Environment for Debian/Ubuntu

2010-01-09T03:58:00.004-05:00

The very first thing you need to do to develop for PHP is to setup a development server with PHP installed, of course. But maybe you're somewhat new to PHP and Apache is a huge, mind numbing universe of options. All you really want is the ability to run PHP and map hostnames to code, right? Almost always that's my goal, anyway.

Well, I've done all the work for you. Congrats! Actually, I did it mostly for myself and I'm sharing it with you! Yay for us!

What You Need

A computer with Ubuntu installed and working; I'm using 9.10 as I write this
An Internet Connection

Scope
We are going to setup a new, portable Apache server instance on Ubuntu 9.10 that listens on all of your computer's IP addresses and maps the hostnames being requested from that computer to directories on your hard disk. This means that you can add websites without restarting or reconfiguring Apache in any way. You just create a new directory and Apache figures it out for you. Brilliant, no?

What do I mean by portable? I mean every configuration file, content and scripts you need to run that entire Apache instance is in one folder that is not part of the operating system. You can copy that folder to any other Ubuntu/Debian box and execute the script to start it without any modifications of any kind. All you need is to install Apache2, PHP5 and some other modules. You aren't even using the init script that Ubuntu provides (because theirs sucks; it even says so in the comments).

Preliminary Setup
You need to install Apache, PHP and xdebug and then configure things. Open a terminal (Applications->Accessories->Terminal) and run these commands in this order:

sudo apt-get install php5 libapache2-mod-php5 php5-xdebug # Install Apache/PHP
sudo update-rc.d -f apache2 remove # Disable Apache Service
sudo /etc/init.d/apache2 stop # Stop Apache Service
sudo a2enmod php5 # Enable PHP5
sudo a2enmod vhost_alias # Enable Virtualhost Aliasing

Environment Preparation
Now that we have installed, configured and disabled the system-wide Apache instance we need to extract my handy Apache environment and set it up.

Open a terminal (Applications -> Accessories -> Terminal) and run the following commands:

# Download the file to your home, extract it to /srv and name it something handy
cd
wget http://www.webaugur.com/wares/files/apache2-portable-latest.tar.gz
pushd /srv
sudo tar xvzf ~/apache2-portable-latest.tar.gz
sudo mv apache2-portable* development
pushd development
# Run this script as whichever user account is going to be developing code
bin/fixperms
# start the service
sudo etc/init.d/apache2 start
# Next we want to symlink it into the init system so it starts up at boot
sudo ln -s /srv/development/etc/init.d/apache2 /etc/rc2.d/S91apache2-development

You should now be able to open http://localhost/ in your browser and see your phpinfo() output.

Adding Content
I have prepopulated a simple test script into www/localhost/public/index.php so you can see if its working right away.

The way it works is very simple. If you point a hostname (either in DNS or in your /etc/hosts file) to any of your computer's IP addresses Apache will serve up content from www/hostname/public. So, lets say you point www.ilikeapache.foo to your computer. You will place your content into www/www.ilikeapache.foo/public for Apache to find it. You can symlink many hostnames to a common directory as needed. You might create a link called www/ilikeapache.foo that points to www.ilikeapache.foo, for example. Thus serving up the same content for both host names. Much less ugly than slaving over hot config files into the wee hours of the morning. Simply amazing if you have hundreds of hosts pointing to one server.

What you Get
Here's where you may get a little lost if you're new to all of this. And I'll show you how to use some of this stuff in future articles. So just hang tight if you're not sure how all of this works.

By default, I have configured full on debugging of every kind. So don't go putting this up on a high traffic site as-is. I've done it and it'll run the box out of RAM and swap in under an hour and come crashing to the ground.

Here's a breakdown of useful directories and files in the default config:

var/log/apache2/access_log - Access log with hostname in the first column
var/log/apache2/error_log - Regular error log file
var/log/php.log - PHP Error Log (tail -f var/log/php.log to see errors in realtime)
var/log/xdebug - PHP xdebug stack traces and cachegrind (memory profiling) dumps
var/spool/mail/ - All outgoing email is intercepted (using bin/mailtrap as the "sendmail" program) and dropped here, one email per (timestamped) file. Files are stored in a format that can be piped directly into sendmail for real delivery.
lib/cgi-bin - If you create this directory it will be a common /cgi-bin for all hostnames on this Apache instance.
etc/apache2/include/php5.conf - a symlink that can pointed between debug and production PHP5 config files for quickly moving an instance between production and development.
etc/apache2/sites-templates/ - Examples of how to manually configure a hostname in this setup; both for HTTP and HTTPS.
etc/apache2/run - PID and lock files for this Apache instance

Why Oh Why
Some questions and answers I expect you'll have.

Q: Why do I place content in a hostname/public subdirectory?
A: You should never put your application code in a public directory. Zend Framework uses the convention of having a directory named "public" that maps URLs into your application code. I use ZF quite a lot and therefore followed this convention.
Q: Can I run more than one instance of Apache like this?
A: Absolutely, this is why I wrote my own init script. You can have as many Apache instances as you have IP addresses to give them. Modify etc/apache2/sites-available/mass-vhost.conf to Listen on a specific IP address instead of all IPs. You can have one instance on multiple IPs, as well. Just make sure none of the instances are listening on all IPs (or each other's IPs) or you'll have port conflicts.
Q: How do I move my code and apache instance to another server?
A: Run the setup and preparation steps above on the new host and instead of downloading my copy of the apache-portable just copy your entire directory containing your instance and content from /srv on the current machine to /srv on the new machine.

Troubleshooting and Corrections
If you run into troubles check the var/log/apache2/error_log for relevant problems. If you get completely stumped maybe I missed a step. Feel free to email me with a description of your problem and I'll try to take a look.

Background
I've been using web servers since 1994. I started using NCSA HTTPD and later switched to Apache as it become popular. I was even once part of the first team to port Apache to Windows back in the late 90s. Neat, huh? (No, Windows sucks. It was anything other than neat but it was a challenge.) I've written modules in C and I even modified the indexer module to support XML back when the XML specs were first being drafted (but my changes admittedly weren't generic enough and someone else did a better job later on). I've been using Apache since the beginning and I'm continually amazed at its capabilities.

Pumpkin Pie

2009-11-28T00:04:00.002-05:00

Utensils

Stand mixer
Bowl scraper
Measuring cups
Measuring spoons

Ingredients

1 1/4 cups pumpkin puree, canned or fresh
3/4 cup sugar
1/2 teaspoon salt
1/4 teaspoon ground ginger
1 teaspoon ground cinnamon
1 teaspoon all-purpose flour
2 eggs, lightly beaten
1 cup evaporated milk, undiluted
2 tablespoons water
1/2 teaspoon vanilla extract
1 unbaked pastry shell (9-inch)

Directions
Combine pumpkin, sugar, salt, spices, and flour in your mixing bowl. Add eggs; mix well. Add evaporated milk, water, and vanilla; mix well. Pour into pastry-lined pie pan. It is important that you do not mix the pie filling too much or it will split while baking. Bake at 400° for 15 minutes; reduce heat to 350° and bake about 35 minutes longer, or until center is set. Do not overcook the pie or it will split and crack while cooling. If it looks done its probably overcooked.
Serving Suggestion
Serve warm with whipped cream and vanilla bean ice cream or cold milk.

Rum Cake

2009-11-27T23:44:00.004-05:00

Utensils

Stand Mixer
Bowl Scraper
Measuring cups
Measuring spoons
Nut Chopper
10 inch tube pan
-or-
12 cup bundt pan

Cake ingredients

1 cup chopped pecans or walnuts
18 oz yellow cake mix
3¾ oz instant vanilla pudding mix
4 eggs
½ cup cold water
½ cup wesson oil
½ cup Bacardi Select dark rum (80 proof)

Glaze Ingredients

¼ cup butter
1 cup granulated sugar
½ cup Bacardi dark rum (80 proof)
¼ cup water

Cake Directions
Preheat oven to 325° F.
Grease and flour 10 inch tube or 12 cup bundt pan.
Sprinkle chopped nuts over bottom of pan.
Beat all cake ingredients together until batter is smooth and silky.
Pour cake batter over nuts.
Bake cake for 1 hour.
Cool then invert on a plate.
Prick top and sides with a fork to allow cake to absorb the glaze.
Spoon glaze mixture over the top and sides of the cake until all
of the glaze is absorbed into the cake.
Glaze Directions
Melt butter in a pan and slowly stir in the water and sugar.
Boil sugar and water mixture for 5 minutes stirring constantly.
Remove from heat and stir in rum.

Baked Pineapple BBQ Chicken

2009-11-27T21:38:00.003-05:00

Utensils

baking dish
knife

Ingredients

Frozen chicken tenders or breasts
1 can of pineapple chunks or rings in juice (not syrup)
Bell pepper
-or-
Frozen julienne cut mixed bell peppers
1 small onion
BBQ sauce (see: Poor Man's Barbecue Sauce)

Directions
Preheat oven to 350° F. Arrange diced onion and julienne cut bell peppers into a single layer on the bottom of your baking dish. Pour a few ounces of the pineapple juice from the can into the baking dish. Arrange your chicken into a single layer on top of the peppers and onions. Place the pineapple around the chicken. Pour the barbecue sauce over everything. Bake for 90 minutes (or until the chicken is thoroughly cooked) at 350° F.

Poor Man's Barbecue Sauce

2009-11-27T21:05:00.003-05:00

Utensils

Spoon
Bowl
Sauce Pan

Ingredients

2 cups ketchup
½ cup yellow mustard
¼ cup worchestershire sauce
1 cup dark brown sugar
1 teaspoon kosher salt
1 tablespoon chili powder (optional)
1 tablespoon paprika
1 teaspoon ground black pepper
1 teaspoon lemon juice
-or-
1 teaspoon pineapple juice
1 teaspoon apple cider vinegar

Stove Top Directions
I make the sauce on the stove if I plan to use it on cooked food.

Combine all ingredients into the sauce pan and mix well breaking up any clumps of sugar. Heat mixture until it just begins to boil. Reduce the heat slightly and continue cooking the sauce until it thickens; stirring frequently. Once the sauce reaches your desired thickness its ready to use!

Microwave Directions
I often use the microwave if I intend to use the sauce for basting. You may not want the sauce to be very thick if you intend to cook it further. You mainly just want the sugars to dissolve.

Combine all ingredients into a microwave safe bowl and mix well breaking up any clumps of sugar. Heat the mixture until it boils (about 2 minutes). Remove the sauce and stir it well. Continue heating the sauce at 50% power until it reaches the desired thickness; stirring frequently.
Serving Suggestions
Goes well with chicken or pork!

PHP 102: Whitespace Matters!

2009-11-23T14:19:00.011-05:00

Lets start at the beginning. Lets start with creating a blank PHP script. What's one of the most important things to remember when creating a new PHP script? I'll tell ya: Whitespace Matters!

You must keep track of your whitespace in PHP scripts. Why? HTTP headers cannot be set if you have already "printed" any characters. Stray spaces before and after segments will, among other things, prevent you from setting HTTP headers (e.g. session cookies, redirects, and so on).

This is something I run into over and over and over and over in modifying carelessly written code. Sometimes this is the work of a well intentioned developer trying to make code "more readable". Worse, this is a problem you won't catch until its too late. You can code for months or years on a project and never notice any problems. Until one day everything explodes for no obvious reason. There are huge, massive projects out there that still haven't completely learned this lesson.

Opening Demarcation
If your script contains only PHP code then it must begin with <?php at the very beginning of the file. No spaces. No new lines. <?php should be the very first characters in your new file. Don't use asptags <%, don't use shorttags <? or any other cutesy business.

Closing Demarcation
If your script contains only code and no embedded HTML markup then it must never include a ?> closing tag. Never. Ever. Yes, of course it'll work. Don't do it. Omitting the closing ?> ensures that all trailing whitespace will be in a code segment and not your output buffer.

Good Example

<?php
function helloWorld(){
  return 'Hello World!';
}

echo helloWorld();

Bad Example




<?php
function helloWorld(){
  return 'Hello World!';
}

echo helloWorld();

?>

Veggie Tacos

2009-09-27T15:23:00.003-04:00

Utensils

measuring cups
knife
skillet
spatula

Ingredients

⅓ cup vegetable oil
pinch kosher salt
1 cup chopped onions
⅓ red bell pepper
⅓ yellow bell pepper
⅓ orange bell pepper
-or-
1 large red bell pepper
(optional, to taste) Sliced Jalapeños, pickled or fresh (sweet pickled are great)
6 ounces Morning Star Farms Griller Recipe Crumbles
1 tablespoon chili powder (2 tablespoons if no jalapeños)
1 cup brown rice
1 cup water

Directions

Heat up skillet to medium-high and add oil and salt. Allow oil to heat thoroughly.
Cook onions in hot oil until translucent but don't allow them to caramelize.
Add bell peppers and caramelize onions and peppers.
Add jalapeños and Morning Star crumbles
Thoroughly cook the crumbles.
Add chili powder, rice and water.
Turn temperature down to medium.
Cover and allow rice to absorb the water (5-10 minutes).
Uncover and turn heat up to high and cook until there is no remaining water allowing the rice and other ingredients to brown slightly.
Turn off the heat and enjoy!

Serving Suggestions
Heat fresh corn tortillas (made from masa harina not cattle feed) in an iron skillet until they just bubble. (This takes practice if you've never done it.) My preference is to then take two cooked tortillas and "glue" them together slightly offset using a bit of queso blanco. Makes for a slightly larger and more robust taco. Fold the tortilla(s) and fill with vegetarian beans (no lard), the filling mix we just made and fresh veggies. You may want to include some shredded cheese.

Fake Windows Antivirus Scams

2009-09-19T11:53:00.007-04:00

Seems like any time you search for Facebook these days one of the top results sends you to a fake anti-malware website trying to trick you to install actual malware. I suspect it looks pretty convincing to those people using Windows PCs. However, I'm running Ubuntu 9.04 on all of my computers rather than Windows. Ubuntu is a full UNIX-like operating system similar to MacOS X but based on Linux instead of Steve Jobs ego. So these things just look ridiculous to me. My computers look absolutely nothing like a Windows desktop.

Fake Warning
Oh dear, my system must be filled with viruses! NO! Oh, wait, right, maybe they are lying to me.

Fake My Computer Screen
So, the first thing it does is show you something that looks like the Windows My Computer screen. This sticks out like a sore thumb on a non-Windows computer, as you can see. It has information (IP address, your city, etc) plastered about that claims to be personal information. Well, there's nothing personal about the info its showing. It doesn't even bother to try to show you a real view of your own computer. It just makes everything up. Close enough to scare most people, I guess.

Fake Infection Detection
Oh my goodness, it says my computer remains infected despite their best efforts. I had better let them heal my computer. Benny Hinn would be proud. Now, where did I put my electrified microphone and rubber floor mat...

Fake Virus List
Wow, look at all of those things that Windows security detected. Wait, Windows security? On a UNIX system? Umm. I must have let those mushrooms sit in the fridge a little too long. I'm starting to see things.

The Real Threat
Oh, now lookee here. It wants me to run this handy "removal" tool. How very nice of it. My system is offering to run it with Wine, a Windows program loader for UNIX systems.

Moral
Don't run programs that you didn't ask for. Don't believe what everyone tells you. Doubly so on the web.

Crock Pot Barbecue Chicken

2009-09-10T17:54:00.003-04:00

Utensils

Measuring cups
Measuring spoons
Small mixing bowl
Crock pot

Basic Ingredients

1 medium onion, chopped
1½ teaspoons minced garlic
3lbs skinless chicken (boneless if you prefer)

Sauce Ingredients

⅔ cup ketchup
⅓ cup packed brown sugar
1 tablespoon chili powder
1 tablespoon lemon juice
1 teaspoon dried basil
½ teaspoon salt
¼ teaspoon pepper
⅛ teaspoon hot sauce

Thickener Ingredients

2 tablespoons cornstarch
3 tablespoons cold water

Directions

Basic: place onion and garlic in the bottom of the crock pot and top with chicken.
Sauce: combine all ingredients in a mixing bowl and pour over the chicken.
Cook on low for 5-6 hours.
Remove only the chicken from the crock pot.
Thickener: Mix corn starch and water until smooth.
Pour thickener mixture into the crock pot and stir until thoroughly mixed.
Cook on high for 15 minutes or until thick.

Serving Suggestions
Serve chicken over a bed of rice with sauce poured over the top.

Serve chicken with mashed potatoes and corn or beans.

Whole Wheat Bread

2009-08-18T00:44:00.007-04:00

Utensils

Measuring cups
Measuring spoons
Small mixer with dough hooks
- or -
Bread machine
Cooling rack
Small bowl
Pastry brush

Dough Ingredients

1 ½ cup warm water
1 tablespoon vegetable oil
3 tablespoons pure honey
½ teaspoon salt
1 cup whole wheat flour
1 ¼ cup whole wheat pastry flour
1 ¼ cup bread flour (white flour)
⅓ cup wheat gluten flour
2 teaspoons active dry yeast (1 packet red star)

Crust Ingredients

⅓ cup melted salted butter

Mixing Directions
Place all of the dough ingredients into your mixer or bread machine in the order given. When adding the yeast make a dimple in the center of the flour and pour the yeast into it. This prevents the yeast from contacting the water or salt until mixing begins.

Baking Directions
Oven
Once the dough has been kneaded and allowed to rise for an hour remove the dough from the mixer bowl or bread machine. Place onto a lightly floured surface and gently flatten the dough to a bit less than an inch thick. Shape the dough so it fits your bread pan leaving the top smooth. Cover the pan loosely with a clean kitchen towel and allow the dough to rise for about one hour. The top of the dough should have risen to about 1 inch above the top of the pan.

Bake at 375 F until bread internal temperature reaches 325 F. For darker crust bake at 400 F but watch it closely. This should take 25-30 minutes. If you weren't paying attention and the crust seems burnt don't worry quite yet.

Bread Machine
Select an appropriate whole grain or french bread program, select crust color and press start.

Finishing the crust
While the bread is still hot remove it from the bread pan and place on a wire cooling rack. Melt the salted butter in a small bowl and use the pastry brush to cover the entire loaf of bread in butter. You won't need more than one coating of butter. Allow the bread to cool to just above room temperature and place in an air tight container or sealed bag. After a few hours in a sealed container the crust of the bread will soften. If your crust seemed burnt then you may find the butter has saved it.

Yield
One 2 pound loaf

Tips

If you are using a full size standing mixer with dough hooks you may need to double or triple the recipe and make 2 or 3 loaves in order for the dough hooks to work properly. Use a bread machine for making single loaves.
Don't bake the bread in the bread machine unless you are in a hurry. The bread should bake fine but it will likely be lumpy. For a "perfect" loaf bake one or two loaves in a regular bread pan in a conventional oven.

Front Page Change

2009-08-18T00:30:00.002-04:00

I've changed the "front page" of this website to show only blog posts of general interest. This, currently, is the only such post. You can read all of my posts by going to my blog page.

Boxee

2009-06-08T03:01:00.003-04:00

Here I sit, unable to sleep, watching Fantasy Island on Hulu with Boxee. Tattoo was just announcing, "De Plane! De Plane!" Tattoo is trying to convince the boss to give him his fantasy.

I haven't watched live television in about 6 months, I guess. I got a 34" 1080p HDTV around Christmas. So I built a Home Theater PC running Ubuntu 8.10 to use with it. I have a large library of movies and tv shows. So it made sense that I would organize them with the computer. As I was looking for software to do that Boxee was becoming popular. Boxee is definitely beta quality but it is headed in a fantastic direction. I wish it was better able to integrate online content with local content. But its so good there's just no point in watching live tv.

"Let's see some sunshine on that Cherubic face of yours." -- De Boss, De Boss!

php-imap extension == evil

2009-06-04T18:14:00.003-04:00

The Problem

The PHP IMAP extension relies on University of Washington's libc-client IMAP library which appears to be written by kindergarteners. After some review of the source code, UW's IMAP client library appears to have extensive, serious security and stability problems at very fundamental levels.

I'm seeing segfaults (buffer overflows) performing simple operations like fetching attachments. Some attachments work fine but others fail; larger files especially. There are bug reports and CVE entries related to similar issues. However, upgrading to the supposed "fixed" versions of everything does not make any difference for my specific issue. It does fix some other issues related to this. (i.e. the exact same programming errors that appear to affect thousands of lines of code in the UW client.)

The Solution

Use one of the many native IMAP class library. My choice would be Zend_Mail as we use Zend Framework extensively here at work. Zend_Mail supports a number of other mail protocols in addition to IMAP. MIME type support is likely much better than other options. The other logical choice would be Pear Net_IMAP.

MySQL Master-Master-Slave(s) Database Replication

2009-04-09T11:04:00.008-04:00

I have watched the technology sessions and slideshows explaining how many large websites, such as Google or Facebook, setup their MySQL Databases. But none have ever gone into the details of how to configure MySQL in such a way. So I had to tackle that myself. I am documenting the process here so its hopefully useful to others (and myself when I forget in 6 months).

Overview of the resources involved

Server farm composed of Sun Fire x2250 servers
Sun StorageTek 2510 iSCSI storage arrays
All servers run Red Hat Enterprise Linux Cluster Suite 5.3
MySQL 5.1 from Remi has been installed (Merci Remi!)
Masters are on bare-metal with a pair of RAID-1 250GB disks, 8 cores, 16GB RAM
Slaves run as cluster services on RHEL 5.3 backed by the iSCSI arrays, 4 cores, 4GB RAM

Data Integrity Concerns
The very first thing you need to consider is that MySQL technically does not support multiple masters. This is significant because it means that there is no conflict resolution if you write data to both masters. If you happen to change the same record on both masters they wipe each other's changes out. MySQL replication works simply by replaying queries from the master on the slave server.

The safest solution is to simply never write data to both masters. Although, there are strategies that allow you to safely write to multiple masters. For example, limit writes to specific tables on each master server. In my case I use the secondary master as a replication source and hot-spare in case I need to take down the primary master for maintenance. Using the secondary master as a replication source takes the burden of slave replication off your primary database server.

Master Configuration
We have two masters. They are identified as 1 and 2. (Slaves are 11, 12, etc.)

The very first thing you should do is to run /usr/bin/mysql_secure_installation on each of your masters to set MySQL's root password and other security settings.

Master 1
Add the following to the [mysqld] section of my.cnf making the appropriate changes and restart mysqld:

# primary master server id
server-id=1
auto_increment_offset=1
# total number of master servers
auto_increment_increment=2
# local slave replication options
log-bin=master1-bin
log-slave-updates
# remote master replication options
master-host=master2.yourdomain.com
master-port=3306
master-user=replica
master-password=replic8
master-connect-retry=10

Master 2
Add the following to the [mysqld] section of my.cnf making the appropriate changes and restart mysqld:

# secondary master server id
server-id=2
auto_increment_offset=2
# total number of master servers
auto_increment_increment=2
# local slave replication options
log-bin=master2-bin
log-slave-updates
# remote master replication options
master-host=master1.yourdomain.com
master-port=3306
master-user=replica
master-password=replic8
master-connect-retry=10

Create Replication Accounts
On both master servers run the following query as root:

mysql> GRANT REPLICATION SLAVE ON *.* TO 'replica'@'%' IDENTIFIED BY 'replic8';

Dump/Load Existing Data and start Replication

On Master 1
Prevent writing to the database.

mysql> FLUSH TABLES WITH READ LOCK;

mysql> SHOW MASTER STATUS\G
*************************** 1. row ***************************
          File: master1-bin.000001
      Position: 254
  Binlog_Do_DB:
Binlog_Ignore_DB:
1 row in set (0.20 sec)

Make note of the position and file name. You must have these later. From a terminal you now need to dump the database for loading onto the slaves.

bash> mysqldump -A -u root -p > master1.sql

On Master 2
Load the data from Master 1 onto Master 2.

bash> mysql -h master2.yourdomain.com -u root -p < master1.sql

Enable Master 2 as a slave to Master 1 (refer to master 1's show master status above for MASTER_LOG* values)

mysql> CHANGE MASTER TO
MASTER_HOST='master1.yourdomain.com',
MASTER_USER='replica',
MASTER_PASSWORD='replic8',
MASTER_LOG_FILE='

master1-bin.000001

',
MASTER_LOG_POS=254;
mysql> START SLAVE;

Get the Log Info for Master 2

mysql> SHOW MASTER STATUS\G
*************************** 1. row ***************************
          File: master2-bin.000005
      Position: 12314580
  Binlog_Do_DB:
Binlog_Ignore_DB:
1 row in set (0.00 sec)

On Master 1
Enable Master 1 as a slave to Master 2 (refer to master 2's show master status above for MASTER_LOG* values)

mysql> CHANGE MASTER TO
MASTER_HOST='master2.yourdomain.com',
MASTER_USER='replica',
MASTER_PASSWORD='replic8',
MASTER_LOG_FILE='

master2-bin.000005',
MASTER_LOG_POS=

12314580;
mysql> START SLAVE;

Master-Master Setup is complete
If all you wanted was a master-master setup then you are finished. Any query executed on master 1 will also be executed on master 2.

Adding Slaves to your Master-Master

On Each Slave Follow this Procedure
Add the following to the [mysqld] section of my.cnf changing the server-id and master settings as appropriate and restart mysqld:

# this slave's server-id
server-id=11
# replicate from master 2
master-host=master2.yourdomain.com
master-port=3306
master-user=replica
master-password=replic8
master-connect-retry=10

Load the data dump from Master 1, if needed:

bash> mysql -h slave11.yourdomain.com -u root -p < master1.sql

Start Replication from Master 2 to each slave (refer to master 2's show master status above for MASTER_LOG* values)

mysql> CHANGE MASTER TO
MASTER_HOST='master2.yourdomain.com',
MASTER_USER='replica',
MASTER_PASSWORD='replic8',
MASTER_LOG_FILE='

master2-bin.000005',
MASTER_LOG_POS=

12314580;
mysql> START SLAVE;

Master-Master-Slave Setup is Complete
Congratulations, you are done with the server configuration! You may verify this by inserting or updating records on Master 1 and then verifying that the change is made on Master 1 and all of your slaves.

Client Access Considerations
To take full advantage of this configuration your client applications will need to be written in such a way that they perform all critical writes (that is, writing data that you want to keep) on Master 1. Also consider that some or all reads immediately following a write may need to come from the master. This is because it can take a few seconds for the slaves to synchronize with Master 1. This is what we call a "dirty" read. Clients performing only reads or creating temporary tables for use with those reads can access your pool of slaves and never touch the master.

Examples

Generate query-intense reports on dedicated slaves.
A portal page that doesn't need up-to-the-second data.
Statistics calculations can be performed on the slaves.

Enforcing Safe Practices
You would be well advised to GRANT only SELECT privileges to clients accessing your tables via a slave. This way a rogue client application cannot manipulate upstream data on the slave. Any changes made on the slave would not be known to any other slave nor the masters. This could be a devastatingly bad situation to find yourself in. Please think through these issues before you implement your clients.
You almost certainly will want to allow clients to create temporary tables, though.

Advanced Stuff
MySQL doesn't require slave tables to have the same schema as masters, either. This allows you to do interesting things like create your master database tables as InnoDB tables with full referential integrity and foreign keys while creating your slave tables as high performance MyISAM tables. You can create different indexing strategies on the slaves to fine-tune specific slaves to specific tasks such as report generation.

Red Hat Enterprise Linux Cluster Suite 5.2 DHCP Problems

2009-03-20T16:06:00.003-04:00

Well, I learned another valuable clustering lesson today. Manually assign all of your IP addresses and do not rely on DHCP. I'd still suggest you have the IPs statically assigned on the DHCP server but don't rely on it at all.

Yesterday I rebooted all of the machines in the cluster simultaneously after making some extensive modifications to the iSCSI configuration on them all. (I'm using cluster-ssh to manage them all simultaneously.) All of the machines went down at exactly the same time and came up at exactly the same time. (They are identical hardware with identical software, afterall.)

Today, for whatever reason, when all of the leases expired at roughly the same time they didn't renew quickly enough. I walked out of a meeting this afternoon to all of the cluster nodes reporting "Quorum dissolved" and all services on the cluster were failed.

Red Hat Enterprise Linux Cluster Suite 5.2 Relocate Problems

2009-03-11T16:58:00.006-04:00

Gist of it all
So, I've been fighting mind bending failover problems on our new compute cluster at work for the past week. I can summarize the solution to service failover problems in one sentence:
Don't use Red Hat's cluster service scripts, evar.

How it actually works
Apache's script (apache.sh) in RHEL 5.2 sends a TERM signal to Apache, waits N seconds (0 by default for Luci/Ricci, 20 for sys-config-cluster) and then proclaims that Apache has failed to shutdown if its still running. This type of failure is fatal for the cluster service.

How it should work
The standard apache init scripts (/etc/rc.d/init.d/httpd) do the right thing, more or less. The parent process is sent the TERM signal, waits 10 seconds and if its still running sends the KILL signal. That may seem harsh but this is a web server for crying out loud. There's no real chance of data corruption if you KILL the web server. If something goes horribly wrong and Apache needs to move to another machine I'm quite happy with Billy Bob having to retype a form or resume his download. That affects only Billy Bob. Bringing down the service for the entire world, in comparison, seems like a very bad solution.

Rant
Red Hat has spent years developing this clustering software. Its fairly good and seems reasonably well written. Its a shame they only spent 5 minutes writing the service scripts. The stock init scripts are infinitely better written but won't work in a clustered environment.

Solution
So, my advice, spend 20 minutes and write your own userscript for each service. If a service is important enough to be on a cluster you can afford to spend the time to write your own script to start and stop it. If you don't know how to write shell scripts and you're managing a cluster then do everyone a favor and seek employment at McDonalds.

Howto
User scripts for the cluster are simply LSB compliant init scripts. I advise you to not waste much time trying trying to hack the /etc/rc.d/init.d scripts to work within the cluster. You can do so but you'll end up stripping out most of it. You may wish to source the /etc/rc.d/init.d/functions file, though. But you will need to pass the pid filename to every single function you call. (Read the functions script to see which options to pass to each function. daemon, killproc, and status functions are most useful for starting, stopping and checking status respectively.)

Vote

2008-11-04T06:13:00.000-05:00

Uncle Sam needs you...to vote!!!

Beware DVDs, CDs created on Windows Vista

2008-11-03T15:01:00.006-05:00

Windows Vista uses a new DVD/CD format that nothing else supports. So, if you are making DVDs or CDs for friends on a Windows Vista machine then your friends probably won't be able to read it unless you've manually changed the disc writer settings to "Mastered" each time you burn a disc.

This is, of course, standard operating procedure for Microsoft: Introduce some new whizbang format (documents, disks, etc) into their latest products in an attempt to force the rest of the world to use their latest software. I don't care how much better someone at Microsoft thinks it is... If the rest of the world can't read the disc its nothing more than a worthless piece of aluminum foil glued to a coaster.

Update: Ubuntu Linux 8.10 can read LiveFS formatted discs.

Farewell Furball

2008-08-27T00:15:00.003-04:00

Well, my mother's cat "pookie" went into renal failure from diabetes yesterday. He lived a long, full life and seemed quite happy for most of it. The old guy will certainly be missed.

So long and thanks for all the fish...

Linux & Vista Slow Internet

2008-08-25T16:01:00.003-04:00

If you are seeing slow Internet speeds under Linux (2.6.17 or newer) or Windows Vista make sure your router supports RFC 1323. If it does not then this is likely your problem. To fix it, upgrade or replace your router. RFC 1323 is a performance enhancement for TCP/IP networking which LInux and Vista support. Unfortunately, it seriously hurts performance if the network hardware doesn´t support it properly (or at all).

Web Development Resources

2008-07-20T07:38:00.003-04:00

I have been working on a web development resources listing for tools and services I use every day.

It can be found at: http://sites.google.com/a/webaugur.com/web-development

Family

2008-07-17T12:31:00.005-04:00

Well, some family members are upset about me publishing public domain information about deceased family members exported from the 1998 Family Tree Maker CDs and federal government's master death file (aka Social Security Death Index). I'm not going to censor bits and pieces of publicly available information for one or two people. I have much better things to do with my time. So I have removed absolutely everything.

These very same people don't invite me to family events, don't let me know when loved ones pass away or if I somehow end up at a family event they make snide comments about me being there.

Its a real shame, too. I've met more family members by publicly posting old family photos than I ever met through direct interaction with relatives. Its telling that I've learned more about my family history from my father's uncle's grandson's ex-wife, whom I've never met, than my own relatives.

15k 500 Festival Mini Marathon

2008-04-12T08:43:00.002-04:00

One of the first runners blurs past mile marker 2.

Tail end approaches mile marker 1.