Ohai Plugin for OpenVZ VMs to get public IP Address

Media Temple uses the OpenVZ virtualization system and I have quite a few Media Temple servers under Chef management. The one thing that has made management difficult is that by default during a Chef run ohai returns 127.0.0.1 as the default IP address which means I cannot run knife to execute commands from my workstation.

For example, when I run knife node show mydv.server.com I get the following:

$ knife node show mydv.server.com

Node Name:   mydv.server.com
Environment: production
FQDN:        mydv.server.com
IP:          127.0.0.1

Kinda sucks. If try to execute on all of my MT servers, say something like knife ssh 'tags:mt' 'sudo chef-client'  I will get a ton of failed connection errors because it is trying to connect to 127.0.0.1.

The solution is to get ohai to return the correct IP. OpenVZ has virtual interfaces and the actual public IP is assigned to them, while the main interface, eth0, is given the ip 127.0.0.1. This ohai plugin will retrieve the correct IP.

provides "ipaddress"
require_plugin "#{os}::network"
require_plugin "#{os}::virtualization"

if virtualization["system"] == "openvz"
  network["interfaces"]["venet0:0"]["addresses"].each do |ip, params|
    if params["family"] == "inet"
      ipaddress ip
    end
  end
end

Put this in your ohai plugins directory for chef: /etc/chef/plugins/openvz.rb and when chef runs, it will get the correct IP address.

Now when I run knife show mydb.server.com

$ knife node show mydv.server.com
Node Name:   mydv.server.com
Environment: production
FQDN:        mydv.server.com
IP:          10.20.30.40