kubetest
is a tool for running tests against a Kubernetes YAML or JSON configuration file.
These tests can be used to enforce local or global best-practices, for example:
- Ensuring certain labels are set
- Prevent usage of images with the
latest
tag - Prohibit privileged containers
- Enforce a naming convention for different resources
kubetest
is currently alpha quality and undoutedly has a few issues. Things will change, hopefully for the better. Please open issues if you have feedback when trying it out.
Tests are written in Skylark, which is a small dialect of Python suitable for embedding in other programmes. This means you do not need an additional interpreter installed to run tests with kubetest
. kubetest
prioritises interopability over flexibility in this regard. Tests for Kubetest just require the kubetest
binary to run. Let's take a look at an example test:
#// vim: set ft=python:
def test_for_team_label():
if spec["kind"] == "Deployment":
labels = spec["spec"]["template"]["metadata"]["labels"]
assert_contains(labels, "team", "should indicate which team owns the deployment")
test_for_team_label()
Save the test file in a directory called tests
, with an extension of .sky
. You can change the default directory name using the --tests
flag. You can now run kubetest
against your configuration files.
$ kubetest my-deployment.yaml
WARN my-deployment.yaml Deployment should have at least 4 replicas
$ echo $?
1
If any of the tests fail then kubetest
will return a non-zero exit code.
By default kubetest
outputs information about failing tests only, but you can pass --verbose
to get information about passing tests as well.
$ kubetest rc.yaml --verbose
INFO rc.yaml should not use latest images
WARN rc.yaml ReplicationController should have at least 4 replicas
spec
is a global variable passed into the Skylark code which contains the structure of the Kubernetes configuration passed in to kubetest
. You'll need to be reasonably familiar with the structure of the Kubernetes API objects to write tests, but it is possible to write helper methods for common assertions.
kubetest
automatically makes available a set of assertions to make writing tests in Skylark more pleasant. A failed assertion results in kubetest
exiting with a non-zero exit code, and assertions output results as shown above.
- assert_equal
- assert_contains
- assert_not_contains
- assert_not_equal
- assert_nil
- assert_not_nil
- fail
- fail_now
- assert_empty
- assert_not_empty
- assert_true
- assert_false
Assertions take zero, one or two arguments (noted above) depending on what they are comparing. They then take an additional message argument which is output when the assertion runs. For example the following assertion checks whether the variable labels
contains the value team
.
assert_contains(labels, "team", "should indicate which team owns the deployment")
Tagged versions of kubetest
are built by Travis and automatically
uploaded to GitHub. This means you should find tar.gz
files under the
release tab. These should contain a single kubetest
binary for platform
in the filename (ie. windows, linux, darwin). Either execute that binary
directly or place it on your path.
wget https://github.com/garethr/kubetest/releases/download/0.1.0/kubetest-darwin-amd64.tar.gz
tar xf kubetest-darwin-amd64.tar.gz
cp kubetest /usr/local/bin
Windows users can download tar or zip files from the releases tab.
$ kubetest --help
Run tests against a Kubernetes YAML file
Usage:
kubetest <file> [file...] [flags]
Flags:
-h, --help help for kubetest
--json Output results as JSON
-t, --tests string Test directory (default "tests")
--verbose Output passes as well as failures
A big thank you goes to the authors of stretchr/testify from where much of the assertion code has been ported.