Have auto-scaling instances name themselves!
Switch branches/tags
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Permalink
Type Name Latest commit message Commit time
Failed to load latest commit information.
bin
lib
spec
.gitignore
.rspec
.travis.yml
Gemfile
LICENSE.txt
README.md
Rakefile
sortinghat.gemspec

README.md

Sortinghat

Sortinghat is a unqiue Ruby gem that allows AWS AutoScaling instances to name themselves.

We all understand that naming your cattle is bad, they shouldn't be pets.. but hostnames are handy and readable, and [insert reason].

When the Sorting Hat is given specific arguments, it can find the gaps in current prefixes or +1 from the last current prefix and name the instance accordingly; along with updating Route53.

It follows a specific pattern for hostnames/fqdn:

[client]-[environment]-[type][prefix].[domain].com.

For example:

nike-prod-nginx09.prod-nike.com

Installation:

Install however you please to your AMI(s) with:

$ gem install sortinghat

Requirements:

The gem itself was developed under Ruby 2.0.0 to work with CentOS 7.

It requires the following gems:

  • aws-sdk 2.1.2
  • pure_json

The v2.1.2 dependency comes from the fact that as of this writting the latest codedeploy-agent (installed via .rpm) breaks if it does not have v2.1.2.

During actually usage, the gem requires that the instance have the following IAM actions allowed via policy:

  • autoscaling:DescribeAutoScalingInstances
  • autoscaling:DescribeAutoScalingGroups
  • ec2:DescribeInstances
  • ec2:CreateTags
  • route53:ListHostedZones
  • route53:ChangeResourceRecordSets

Usage:

Note: The Sorting Hat requires root privileges to write to files under /etc/.

Have cloud-init, cfn-init, or [x/y/z], issue the following command:

$ sortinghat -c [client] -e [environment] -t [type] -r [region] -z [domain]

Note: [domain] should be in the format of [domain].com, just like the AWS Console reports for the HostedZone. No need to add the trailing dot, it will be added should you forget.

The Sorting Hat will log to syslog for information.

The Sorting Hat may be re-run, provided you remove the empty file located at '/etc/.sorted'.

Development

Need to develop on an EC2 instance with metadata available or spoof it somehow.

Clone:

$ git clone https://github.com/praymann/sortinghat

Execute:

$ bundle install

Run:

$ bundle exec bin/sortinghat -h

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/praymann/sortinghat.

License

The gem is available as open source under the terms of the MIT License.