Using the Amazon’s EC2 Cloud seemed like a perfect fit for a short term experiment like this. The approach was to start at the easiest parts and gradually add complexity until we had Tomcat offloading session storage to the Terracotta cluster.

The basic steps were to:

1. Launch an EC2 server instance
2. Perform a basic Tomcat installation
3. Install Terracotta on the same instance and re-configure Tomcat
4. Rinse and repeat to add a second Terracotta instance to the cluster

Launch an EC2 server instance

Start by firing up a t1.micro instance using the Amazon Linux AMI. If you’re using the Amazon EC2 command-line tools, start the instance and then check it has started correctly using these commands.

ec2-run-instances ami-3ac33653 -n 1 -g default -k [keyname] -t t1.micro
ec2-describe-instances

Login to the instance using your favourite SSH client, but make sure that the SSH key specified in the ec2-run-instances command is being used.

Basic Tomcat installation

This AMI already has Java installed (an OpenJDK version), so installing Tomcat simply requires a download of the software, unpack and run the startup script. Make sure that the Amazon Security Group used to start the instance allows access to the Tomcat port (default 8080) on the instance.

Accessing the public DNS name of the Tomcat server should show you the default Tomcat homepage. You can retrieve the public DNS name for any instance in the AWS Management Console.

Terracotta and Tomcat

The open source versions is available from Terracotta downloads.

Following the web sessions install:

1. Extract the Terracotta software
2. Copy the Terracotta jars (terracotta-session-1.1.1.jar, terracotta-toolkit-1.1-runtime-2.0.0.jar) into the $TOMCAT_HOME/lib directory
3. Add a Terracotta configuration (here’s an example) and use the $TERRACOTTA_HOME/bin/start-tc-server.sh to fire up Terracotta and start tailing stdout
4. Add a Valve to the Tomcat context configuration letting Tomcat know to load the Valve and Terracotta config from the URL provided

<Valve className="org.terracotta.session.TerracottaTomcat60xSessionValve" \
    tcConfigUrl="ec2-xx-xx-xx-xx.compute-1.amazonaws.com:9510" />

From your machine, you can fire up the Terracotta Developer Console using the bin/dev-console.(sh|bat) script, but it will be necessary to allow connections to ports 9510, 9520 and 9530. The server host will be the same DNS name used in the tcConfigUrl and port 9530. When starting Tomcat the catalina logs should show that Tomcat has successfully loaded the configuration and the Developer Console will display the sessions in the tree menu on the left.

Add a second Terracotta instance

Launch a second instance, add the Terracotta software, open the required ports (9510, 9520 and 9530; they should be open to each other and to your machine to use the Dev Console) and launch the startup script – you are almost there.

Each of the Terracotta configuration files will need both servers listed (using the same names, in the same order) and then require a restart.

This example is a single server array and provides reliability and failover. For scalability, you will need to add multiple mirror groups.

Gotchas

• You can now stop/start the Terracotta instances indepently and the ACTIVE CO-ORDINATOR role will change. When a server is rejoining, it may complain that it has a dirty cache and that it needs to be manually cleaned up. This can be done by removing the terracotta/server-data directory and then restarting it.
• If the server listed in the Valve configuration is no longer the co-ordinator and Tomcat is restarted, the Tomcat server will not be able to load the config file. Only the co-ordinator seems to answer to this request from Tomcat. Using Elastic IPs to map the current co-ordinator could be a solution for this.
• Make sure you use the external DNS name in the Terracotta configurations if you wish to interrogate them with the Developer Console. The console will obtain the configuration file from the node it connects to, but if the addresses used are not routable from where the console is running you won’t get any results.

Australian’s now prefer to communicate using the Internet rather than a mobile/cellphone. In the 2008 edition of Nielsen’s Australian Internet and Technology Report, 33% of Australian’s preferred to communicate using the Internet and 38% preferred to use a mobile phone. In 2009, the balance had swung to 44% and 31% respectively.

Smartphones are commonplace

The widespread adoption of smartphones is driving enabled mobility. Mobile service usage has increased dramatically with 43% of phones capable of accessing the Internet – with search, news, email and maps amongst the most widely used services.

Business models are being redefined

There has been a huge amount of discussion in recent media over charging for content online. A lot of the coverage has had Rupert Murdoch at the centre. This is a huge shift for the world of online news and services, which have typically been free of charge. However, more subtly, Steve Jobs has also been grooming the world for this change. His iTunes platform has made people very comfortable with handing over 99 cents for a song and the recent iPad launch and early newspaper app sales figures will surely see this flourish.

Consumers are engaged

It has long been the norm for people to review a product online, but recent Nielsen statistics show that 86% of people read reviews or discussions about products or services they intend to pay for and that 63% watched a video online of a product before handing over their hard earned.

For the products with strong customer sentiment, it strengthens their position – for those with bad sentiment, they don’t stand a chance. Consumers can now share their enthusiasm or fight back after a poor experience.

Consumers that aren’t treated fairly have the means and ability to reach massive audiences through flawless distribution like YouTube and Facebook. Be careful about your brands online perception and especially careful about what your own staff could saying about your brand.

Bullish trends for social currency

When you consider the plethora of social websites – how many can you think of that don’t have a competitive angle to them? 4square has their points and mayorships, YouTube has their views, Twitter has their followers, TripIt has their days from home, LinkedIn has their connections and it’s expected that Facebook’s newest currency could potentially become one of the largest global economies.

Social currencies are gaining weight, reputation is now worth more to some folks than money in the bank.

Barriers to social networks are reducing

Amid recent concerns over Facebook’s latest privacy changes, privacy controls amongst the major networks are becoming more sophisticated. An increased ability to filter what is displayed to my friends, family, neighbour or a complete stranger aids in growing a user’s trust in a site, allowing them to flourish from the embryo to the social butterfly.

Nick believes that all sites will soon consider social tools a must have rather than a nice to have and that the term social media as a term.

The social web is all about you: it’s not enough to know that the user likes sport, we need to know that you like Tennis on Wednesday nights and Rugby on the weekends.

The web is improving behavioural understanding – it is moving from observations about similar events to a knowledge of what you need or like and when. We are moving away from the collective intelligence approach that Amazon used to bring us the customers who bought this also bought to this deeper individual understanding.

That said – I think that some of the collective intelligence techniques are very relevant and under utilised to make intelligent suggestions about what the user is trying to achieve.

Websites are constantly using the social currency of reputation to encourage users to participate with their site – increasing engagement and length of site visit. Great for the popularity of their site and the advertising spend. Some great examples of common social functionality we see on the web are:

• tell others what you’re doing
• see the latest activities of people you know
• connect your identities – the activity from sites like Linked In, Twitter, Facebook is intermingled across the web
• build collections of things
• find others like you

The web is moving towards a deeper behavioural understanding from the current models that are used

To view the current process list:

SELECT * FROM V$PROCESS;

For more information on what processes are currently doing, I found this post pretty useful.

I recently had to increase the number of allowed connections to a database, which meant a restart. I did this using:

# sqlplus /nolog
CONNECT / AS sysdba;
SHUTDOWN IMMEDIATE;
STARTUP;


These are pretty basic operations but thought they may be of use to someone out there!

Drucker discusses what he perceives to be the definition of an executive and the role that they play within an organisation. Druckers key take-away points are that:

• Effectiveness must be learned
• Record and analyse where your time goes
• Focus your vision on contribution
• Make the strengths of yourself and others productive
• Items with the most impact should be undertaken first