This gem adds capistrano3 tasks for adding and removing nodes from Amazon's Elastic Load Balancer.

1. Add cap3-elb to your Gemfile

# Gemfile
gem 'cap3-elb'

2. Use upload scm in Capistrano

# Capfile
require 'cap3-elb'

3. Configure the name of the load balancer and your AWS credentials. I suggest storing the credentials in something like dotgpg and using environment variables to avoid storing these keys alongside your code.

# config/deploy.rb

set :load_balancer, "website"

set :aws_secret_access_key, ENV.fetch("AWS_SECRET_ACCESS_KEY")
set :aws_access_key_id, ENV.fetch("AWS_ACCESS_KEY_ID")

This shows you a list of all your hosts along with their load-balancer status.

bundle exec cap elb:status

The elb:add task adds hosts to the load balancer. By default it will add all hosts, but you can filter things to only add one specific host using capistrano's --host flag:

bundle exec cap elb:add --host web1.example.com

The elb:remove task removes hosts from the load balancer. It will abort if you try and remove more than one node at a time, and also if removing the node would result in no healthy instances.

bundle exec cap elb:remove --host web1.example.com

cap3-elb is released under the MIT license, see LICENSE.MIT for details. Bug reports and feature requests are welcome.