I’ve been spending time learning Ansible, the Python-based configuration management framework created by Michael DeHaan. There are two main features that make Ansible worth considering for your configuration management needs: ease of implementation via an agentless design (based on SSH), and a DSL that closely resembles traditional shell scripting command syntax. Ansible “plays” are very easily read and understood whether you are a sysadmin, developer, or technical manager. Having used both Puppet and Chef in the past, which require a client/agent installation, I truly appreciate how quickly one can deploy Ansible to manage servers with minimal overhead and a small learning curve.

One of the best resources I’ve found so far to aid in learning Ansible, in addition to the extensive and quality official Ansible documentation, is Jeff Geerling’s most excellent “Ansible for DevOps.” The author steps you through using Vagrant-based VM’s to explore the use of Ansible for both ad-hoc commands and more complex playbook and role-based management.

All of the work I’ve done with Ansible for this post is publicly available on GitHub, so feel free to clone my ansible-mojo repo and follow along.

Lab setup – Vagrant, VirtualBox, and Ansible

I use a mix of custom VirtualBox VM’s and Vagrant-based VM’s for all of my home devops lab work. For the purposes of this post, I am limiting myself to a Vagrant-based solution as it’s extremely simple and dovetails nicely with the approach in “Ansible for DevOps”. So let’s take a closer look…

I’m using Vagrant 1.8.6 and VirtualBox 5.1.6 (r110634) on my MacBook Pro running Yosemite (10.10.5 w/Python 2.7.11). Historically, most of my recent experience has been with CentOS and AmazonLinux, so I decided to refresh my knowledge of Ubuntu, choosing to use Ubuntu 16.04.1 LTS (Xenial Xerus) for my VM’s using the bento/ubuntu-16.04 image hosted at HashiCorp’s Atlas.

To get started, simply add the bento Ubuntu image to your Vagrant/VirtualBox installation. I store all my Vagrant machines in a directory off my home directory called “vagrant-boxes”:

mkdir ~/vagrant-boxes/bento_ubuntu
cd ~/vagrant-boxes/bento_ubuntu
vagrant init bento/ubuntu-16.04; vagrant up --provider virtualbox

At this point, you should have a working Vagrant machine running Ubuntu 16.04.1 LTS!

Note: I originally started this work using Canonical’s ubuntu/xenial64 official build images for Vagrant. However, I ran into an issue immediately that made provisioning with Ansible a bit wonky, namely the fact that the Canonical image does not ship with Python 2.x installed (Python 3.x is there but is not used for Ansible operations). Be advised of this as you setup your own Ansible sandbox with Vagrant.

Because I like to be able to SSH into my Vagrant machines from anywhere inside my home network, I modify the Vagrantfile to access the VM using a hardcoded IP address that I’ve reserved in my router’s DHCP table. The relevant line if you want to do something similar is:

config.vm.network "public_network", ip: "192.168.0.99", bridge: "en0: Wi-Fi (AirPort)"

I then use this IP address in my local hosts file, which allows me to use it via a hostname of my choosing within the Ansible hosts file.

Next, I had to install Ansible on my MacBook. I could have used the package found within Homebrew, but that version is currently 2.1.0 and I wanted to work from the most current stable release with is v2.2.0. So, I opted to clone down that repo from Ansible’s GitHub project and work from that source:

git clone git://github.com/ansible/ansible.git --recursive
cd ./ansible
source ./hacking/env-setup

The last step configures your machine to run Ansible out of the source directory from the cloned repo. You can integrate the environment settings it generates into your shell profile so that the pathing is always current to your installation. You should now have a working copy of Ansible v2.2.0:

[rcrelia@fuji ansible (stable-2.2=)]$ ansible --version
ansible 2.2.0.0 (stable-2.2 e9b7d42205) last updated 2016/10/20 10:00:56 (GMT -400)
 lib/ansible/modules/core: (detached HEAD 42a65f68b3) last updated 2016/10/20 10:00:59 (GMT -400)
 lib/ansible/modules/extras: (detached HEAD ddd36d7746) last updated 2016/10/20 10:01:02 (GMT -400)
 config file = /etc/ansible/ansible.cfg
 configured module search path = Default w/o overrides

Note: I keep my Ansible files in a directory under my $HOME location, including ansible.cfg, which is normally expected by default to be in /etc/ansible. While you can use environment variables to change the expected location, I decided to just symlink /etc/ansible to the relevant location in my $HOME directory. YMMV.

sudo ln -s /etc/ansible /Users/rcrelia/code/ansible

Using Ansible With Your Vagrant Machine

In order to use Ansible, a minimum of two configuration files need to be used in whatever location you are using for your work: ansible.cfg and hosts. All other content will depend on whatever playbooks, host config files, and roles you create. The ansible.cfg in my repo is minimal with the defaults removed. However, you can find a full version in there named ansible.full.cfg for reference. Additionally, you will want to make sure you have a working log file for Ansible operations, with the default being /var/log/ansible.log. The output from all issued Ansible commands are logged in ansible.log.

Since Ansible uses SSH to communicate with managed nodes, you will want to use an account with root-level sudo privileges that is configured for SSH access, and ideally one that is passwordless. I personally use a ssh-agent process to store credentials and make sure that I configure the nodes to allow access using that private key via authorized_hosts. Do whatever makes sense for your environment.

By default, the bento Vagrant machine ships with a sudo-capable user called “vagrant”, whose private SSH key can be used for the initial Ansible run. I added that key to my ssh-agent:

ssh-add ~/vagrant-boxes/bento_ubuntu/.vagrant/machines/default/virtualbox/private_key

At this point, I can now communicate with my Vagrant Ubuntu VM using Ansible over a passwordless SSH connection. Let’s test that with a simple check on the node using Ansible’s setup module:

[rcrelia@fuji ansible]$ ansible myvm -m setup -e ansible_ssh_user=vagrant|head -25
myvm | SUCCESS => {
 "ansible_facts": {
 "ansible_all_ipv4_addresses": [
 "10.0.2.15",
 "192.168.0.99"
 ],
 "ansible_all_ipv6_addresses": [
 "fe80::a00:27ff:feb5:5b5e",
 "fe80::a00:27ff:fe28:3f0"
 ],
 "ansible_architecture": "x86_64",
 "ansible_bios_date": "12/01/2006",
 "ansible_bios_version": "VirtualBox",
 "ansible_cmdline": {
 "BOOT_IMAGE": "/vmlinuz-4.4.0-38-generic",
 "quiet": true,
 "ro": true,
 "root": "/dev/mapper/vagrant--vg-root"
 },
 "ansible_date_time": {
 "date": "2016-10-26",
 "day": "26",
 "epoch": "1477494044",
 "hour": "15",
 "iso8601": "2016-10-26T15:00:44Z",
[rcrelia@fuji ansible]$

Note that I specify the -e option to specify the default Vagrant user for my Ansible session. This is an override option and is only required for the initial playbook run from ansible-mojo. Once we’ve applied our main playbook, which sets up a user called “ansible”, we can then use that user for Ansible operations going forward (as specified by our remote_user setting in ansible.cfg).

At this point, we have a working installation of Ansible with a single manageable Ubuntu XenialXerus node based on Vagrant. In Part II, I will cover the workings of ansible-mojo and discuss various details around playbook construction, layering of plays, etc.