configure_cluster.rb

# This recipe is intended to be run at the `configure` step
#

directory "/scripts" do
  owner "root"
  group "root"
  action :create
end

template "/scripts/startup_node.sh" do

  @cluster_size = node[:opsworks][:layers]['stag-es'][:instances].size()

  source "startup_node.sh.erb"
  user "root"
  group "root"
  mode "0777"

  Chef::Log.debug("Cluster size #{@cluster_size} reached, building startup script...")
  action :create
  only_if { @cluster_size >= 3 }
  notifies :run, 'execute[startup_eventstore_node]', :immediately
end

execute "startup_eventstore_node" do

  instance_ip = node[:opsworks][:instance][:private_ip]
  other_ips =  node[:opsworks][:layers]['stag-es'][:instances].map{ |name, instance| instance[:private_ip]}.keep_if{|ip| ip != instance_ip}
  gossip_seed = other_ips.map{ |ip| "#{ip}:2112"}.join(",")

  user "root"
  cwd "/scripts"
  command "./startup_node.sh"
  environment "GOSSIP_SEED" => "#{gossip_seed}"
  Chef::Log.debug("Starting eventstore node with gossip seed #{gossip_seed}")
  action :nothing
  not_if '[ -f RUNNING_PID ]', :cwd => "/opt/#{node['eventstore']['installation_directory']}"
end

startup_node.sh.erb

#!/bin/sh

export MONO_THREADS_PER_CPU=100
daemonize -p RUNNING_PID -u root -c /opt/<%= node['eventstore']['installation_directory']%>/ \
    /opt/<%= node['eventstore']['installation_directory']%>/run-node.sh \
    --int-ip=<%= node['opsworks']['instance']['private_ip'] %> \
    --ext-ip=<%= node['opsworks']['instance']['private_ip'] %> \
    --gossip-seed=$GOSSIP_SEED \
    --discover-via-dns=false \
    --cluster-size=3 \
    --run-projections=all \
    --log=/var/data/logs \
    --db=/var/data/db