CLOUD COMPUTING

A list of cloud assignments to be deployed on AWS to help me learn about cloud

Programmatically spinning instances up and down

Installing Ruby

1. Use Homebrew to install ruby

brew install rbenv ruby-build

2. Add rbenv to bash so that it loads every time you open a terminal

   echo 'if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi' >> ~/.bash_profile

   source ~/.bash_profile

3. Install the required Ruby version

rbenv install 2.0.0-p645

4. Set this version on the global environment

rbenv global 2.0.0p645

5. Check if ruby has been properly installed using

ruby -v

*The above command should return the version of ruby installed which should be 2.0.0p645*

GoRails.com has a good tutorial on installing ruby on different operating systems

Do take a look if you have queries Go Rails Ruby installation tutorial

Clone in the repository

The easiest way is to clone in my GitHub cloud_computing repository

git@github.com:subbu1993/cloud_computing.git

##Install the required gems

The first step for working with a ruby application is to install bundler

Run the following at the command prompt

gem install bundler

Then migrate into the ruby_aws directory and run

bundle install

The above command fetches all of the required gems from source and downloads them for the application to use

##Run the task to spin instances up

Set the environment variables for the Access Key and the Secret Key

AAK - Access Key

ASAK - Secret Key

Note you could also copy paste the keys directly in the code (Caution: Do not push it up to github)

The source code for the task is at

ruby_aws/lib/tasks/run_instances.rake

From the directory ruby_aws run

bundle exec rake run_multiple_ec2_instances

Running the above without any arguments spins up one EC2 instance in the region us-west-2

To Provide command line arguments

bundle exec rake run_multiple_ec2_instances[number_of_instances_to_spin_up_or_down,region,start_or_terminate]

Example

bundle exec rake run_multiple_ec2_instances[3,us-west-2,start]

The above command spins up 3 instances in the us-west-2 region

bundle exec rake run_multiple_ec2_instances[2,us-west-2,terminate]

Terminates 2 instances in the us-west-2 region

##Prevent losing money Run the task stop_all_instances using

bundle exec rake stop_all_instances

To stop all instances across all regions.

Use the task as a method to prevent unwanted instances running at different regions