hosts cookbook

default.rb

# Find all other nodes                                                                                                                                                             
nodes = {}
search(:node, "chef_environment:#{node.chef_environment}") do |n|
  # skip current node
  if n[:fqdn] and n[:fqdn] != node[:fqdn]
    nodes[n[:fqdn]] = n
  end
end
Chef::Log.info "Other hosts: #{nodes.keys.sort.join(', ')}"

template "/etc/hosts" do
  source "hosts.erb"
  owner "root"
  group "root"
  mode 0644
  variables(
    :nodes => nodes
  )
end

hosts.erb

127.0.0.1 <%= @node[:fqdn] %> <%= @node[:hostname] %> localhost                                                                                                                    

# Network nodes
<% if @nodes -%>
<% @nodes.keys.sort.each do |fqdn| %>
<%= @nodes[fqdn][:ipaddress] %> <%= fqdn %> <%= @nodes[fqdn][:hostname] %>
<% end %>
<% end -%>

# The following lines are desirable for IPv6 capable hosts
::1 ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts