Managing EC2 Reservations with Ruby

By Ilya Grigorik on September 28, 2007

Over the course of past couple of weeks the guys (and gals!) at Amazon have hosted a number of great 'AWS Start-Up' events to evangelize their services and share the stories of some of the startups that have come to fruition based on their platform. I've had a chance to attend the New York event, as well as present in Boston earlier today - kudos to the AWS team for putting together these events, we've met dozens of exciting new startups, entrepreneurs, and a lot of the AWS team itself.Interestingly enough, watching the presentations and even talking to a lot of the developers in the crowd resulted in very similar pain points: server monitoring, management, and automation. Hence, below is a modest contribution (a Ruby script) for terminating an entire reservation of EC2 instances on the fly. Instead of manually specifying each instance id, you can give it a reservation number (r-xxxxxxx) and all the machines will be shut down:

#!/usr/bin/ruby

reservation = ARGV[0]
if reservation.nil?
    puts "No reservation id"
    exit
end

instances = []
collect = false
`ec2-describe-instances`.each_line { |l|
    l = l.chomp.split("\t")
    if l[1] == reservation
        collect = true
        next
    end

    collect = false if collect and l.first == "RESERVATION"

    instances << l[1] if collect
}

puts "Terminating #{instances.size} servers: #{instances.join(' ')}"
`$EC2_HOME/bin/ec2-cmd TerminateInstances #{instances.join(' ')}`

To use this as any regular EC2 management command copy the provided file into your $EC2_HOME directory, and you're all ready to go. A sample use case would be:

ilya@tux:~$ ec2-terminate-reservation r-f707e49e
Terminating 5 servers: i-348d635d i-378d635e i-368d635f i-098d6360 i-088d6361

Ilya Grigorik is a web performance engineer and developer advocate on the Make The Web Fast team at Google, where he spends his days and nights on making the web fast and driving adoption of performance best practices.
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