How to test your Ansible Deployment with Vagrant

When you start writing Ansible for automating your deployment, one common problem is about testing if it does work as you intend to do it. Some people prefer to do it directly on a server. But then it has all sorts of problems associated (for example when the no. of servers to be provisioned/deployed grows) and I clearly don't like the idea to test Ansible on servers directly. So, I chose the option to use virtual machines using Vagrant.

With Vagrant you could test complex setups like (say) having 4 machines behind a load balancer (just to start with). I've tried to both provision as well as deployment using Ansible + Vagrant. In this post, I'll be quickly covering about testing deployment using Ansible + Vagrant.

In your directory you run Vagrant init; that would provide you a Vagrantfile to start up your virtual machine. Here is a basic configuration that would enable you to boot up an ubuntu machine with a static ip which you could use later to put in your ansible host file.

Vagrant.configure("2") do |config|
  config.vm.box = "ubuntu/trusty64"
  config.vm.network "private_network", ip: "10.0.0.10"
  config.vm.network "forwarded_port", guest: 22, host: 22
end

Now you can boot up your virtual machine using `vagrant up` and try to login using `vagrant ssh`. After ssh-ing into your virtual server; you can do ifconfig to verify that the IP of the server is 10.0.0.10.

In your inventory file you can now mention the IP of the host to `10.0.0.10`, exactly what we mentioned in the Vagrant file.

Your ansible.cfg file can be like this:

[defaults]
inventory = ./virtualhosts
private_key_file = /path/to/project/deployment/.vagrant/machines/default/virtualbox/private_key
remote_user = vagrant
host_key_checking = False

and we'll refer the hosts as virtualhosts, so your virtualhosts inventory file would be like this:

project_web ansible_ssh_host=10.0.0.10 ansible_ssh_port=22 ansible_ssh_user=vagrant ansible_ssh_private_key_file=/path/to/project/deployment/.vagrant/machines/default/virtualbox/private_key

[project]
project_web

[project:vars]
repo_remote=origin
repo_branch=master
DEPLOYMENT_TYPE=DEV

Replace the ansible_ssh_private_key_file with a valid path from your .vagrant directory.

Now try running your Ansible with

ansible-playbook -i virtualhosts playbook.yml

And it's done, with your ansible.cfg, the private ssh key would be correctly chosen for authentication and the playbook would run by user vagrant.

One can model more complex setups with lot of servers and load balancer to mimic actual deployment on servers.