Cluster::Discovery

This is a library that provides a generic interface to multiple cluster providers.

Cluster providers are something that provides metadata about a collection of hosts in a cluster. Supported providers are as follows:

• EC2 Tags
• EC2 AutoScaling Groups
• Consul Services
• Static Lists

Add this line to your application's Gemfile:

gem 'cluster-discovery'

And then execute:

$ bundle

Or install it yourself as:

$ gem install cluster-discovery

To discover cluster instances with EC2 Tags use something like the following example. The keys aws_region, aws_tags(key, value) are all required.

This returns an Array of EC2 Instance Objects

instances = Cluster::Discovery.discover(
  'ec2_tag',
  aws_region: 'us-east-1',
  aws_tags: [{ key: 'Service', value: 'router' }])

instances.map(&:instance_id)

To discover cluster instances by AutoScaling Group use something like the following example. The keys aws_region, aws_asg are all required.

instances = Cluster::Discovery.discover(
  'ec2_asg',
  aws_region: 'us-east-1',
  aws_asg: 'foo-prod-v000')

instances.map(&:instance_id)

To discover cluster instances using Consul use something like the following example. The keys consul_url and consul_service are required, leader, tags, and health are optional.

By default this will only return nodes passing all health checks. To change this behavior set healthy to false.

instances = Cluster::Discovery.discover(
  'consul',
  consul_url: 'http://my.consul.cluster:8500',
  consul_service: 'redis',
  leader: true,
  tags: 'master',
  health: true)
instances.map(&:Address)

TEST_CONSUL_HOST=my.consul.cluster rake spec

Or just:

rake spec

1. Fork it ( https://github.com/rapid7/cluster-discovery/fork )
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request