Nodes & Environments With Test Kitchen

Sat, Apr 4, 2015

I use Chef at work, and I’ve recently embarked on a fair amount of refactoring that includes breaking some cookbooks out of our monolithic chef repo into individual ones. As part of that process, I introduced some testing infrastructure to go along with the new code. In some cases, we only needed to use ChefSpec. In others, test-kitchen was needed to flesh out the testing story.

While the test-kitchen documentation is good enough to get you started, for some non-trivial cases, it’s not sufficient, and the information needed is buried in github issues, on the Chef site itself, or just on random blogs (hey!). I wanted to put together a document that addressed the various use cases that I needed to handle in my testing.

I will assume some basic test-kitchen knowledge. If you haven’t read through the initial docs on the test-kitchen site, go do so now, as it addresses most of the basics.

Using Chef Zero for Provisioning

By default, test-kitchen uses chef-solo to provision the underlying VM. If you want to apply a more complex workflow with your cookbooks, like with environments files or data_bags, you will need to switch to using the chef-zero provisioner.

Switching is actually pretty simple, you simply need to designate the provisioner in your .kitchen.yml file. In that file, you’ll have a provisioner block that needs to be set to look like:

provisioner:
  name: chef_zero

DataBags, Environments, and Nodes

When using chef-zero as your provisioner, you can also specify directories for databags, environments, and nodes in your chef environment. The directories don’t need to be in any specific parent directory. I usually place them directly within the cookbooks top-level test directory. The databag, environments, and nodes configuration entries belong in the provisioner directive.

The provisioner directive block now looks like:

provisioner:
  name: chef_zero
  environments_path: 'test/environments'
  data_bags_path: 'test/data_bags'
  nodes_path: 'test/nodes'

DataBags!

Databags in test-kitchen look just like databags anywhere else in chef. There’s nothing special to know here.

Environments!

You do need to use json files for environments with test-kitchen. I’m not quite clear why that is, as you don’t need to use json files specifically for Chef or chef-zero. Regardless, if you need a particular environment, you can define one to look like this:

{
  "name":"staging",
  "json_class":"Chef::Environment",
  "chef_type":"environment"
}

Nodes!

Nodes are interesting. It seems like something of an antipattern to test your independent cookbook in an environment that requires the existence of many other nodes. However, in my particular case, I was stuck with some design that required the use of chef search to populate some local information. As such, I needed to have some extra nodes defined to satisfy my tests.

Each node can be defined in a json file that looks like this:

{
  "id": "es-01.foo.com",
  "fqdn": "es-01.foo.com",
  "chef_environment": "staging",
  "run_list": ["role[elasticsearch]"],
  "automatic": {
    "ipaddress": "192.168.88.88"
  }
}

For my particular use case, I was searching on roles on a per environment basis, so this basic setup on a node was sufficient to satisfy my needs. Other attributes could certainly be set, but I think that even exposing this particular ability is sketchy.

Wincing my way through software