Testing Ansible playbooks locally

While working with Ansible playbooks, there's great value in testing them locally first, before running them on one or more remote servers. The following section tries to describe how you would do just that on a Vagrant virtual machine running Debian for the github-bot.

Good luck, and have fun!

Prerequisites

• Vagrant: https://www.vagrantup.com/downloads.html

Create a Vagrantfile

Create a directory with a file named Vagrantfile inside it, somewhere outside the build repo directory, as we don't want this in the repo.

The Vagrantfile configures the virtual machine about to be created, with the following:

1. Specify which OS we want
2. Prevent Vagrant from generating a random SSH key
3. Copy your own public SSH key onto the machine
4. Use your SSH key for the root user as well

Vagrant.configure("2") do |config|
  config.vm.box = "debian/jessie64"

  # the insecure key is needed for the first login attempt by vagrant itself
  config.ssh.private_key_path = ["~/.ssh/id_rsa", "~/.vagrant.d/insecure_private_key"]
  config.ssh.insert_key = false
  # fixes "stdin: is not a tty" error when provisioning
  config.ssh.shell = "bash -c 'BASH_ENV=/etc/profile exec bash'"

  config.vm.provision "file", source: "~/.ssh/id_rsa.pub", destination: "~/.ssh/authorized_keys"
  # allows us to ssh into the box as root
  config.vm.provision "shell", inline: "mkdir /root/.ssh && cp /home/vagrant/.ssh/authorized_keys /root/.ssh/authorized_keys"
end

Start virtual machine

You can run vagrant up to start the virtual machine.

Notice which port the virtual machine's SSH port gets forward to, in the example below, the port is 2200.

==> default: Forwarding ports...
    default: 22 (guest) => 2200 (host) (adapter 1)
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2200
    default: SSH username: root

After that command successfully completed, you should be able to connect to that machine:

$ ssh -p 2200 root@127.0.0.1

Remember to provide your correct port in the -p argument.

Edit ~/.ssh/config

You will have to create an SSH alias for the hosts you're running the Ansible playbook against.

In this github-bot example, that means infra-rackspace-debian8-x64-1 because the playbook declares this hostname as the host it runs on.

Add the following to your ~/.ssh/config file:

Host infra-rackspace-debian8-x64-1
  HostName 127.0.0.1
  Port 2200
  User root

With that in place, it's even easier to connect to your virtual machine:

$ ssh infra-rackspace-debian8-x64-1

Run the playbook

Before running the playbook, ensure that the necessary secrets are defined. Try and avoid using production secrets while testing the playbook -- you can add fake secrets to the inventory instead and export NODE_BUILD_SECRETS=/invalid/path/ to make sure the real secrets are not accessible.

While in the build directory, run the playbook using the following command:

$ ansible-playbook ansible/playbooks/create-github-bot.yml

Don't forget to run vagrant down once you are down with the virtual machine.