A CLI, which helps you to work with and deploy plain Kubernetes YAML files.
MIT License
A CLI, which helps you to work with and deploy plain Kubernetes YAML files.
There are many great tools out there to manage Kubernetes manifests, e.g. ksonnet or kustomize. They try to make working with manifests easier by deduplicating config. However they usually introduce other configuration files, which comes with complexity on its own. I wanted something simpler, especially for smaller applications.
So here is kyml
:
brew install frigus02/tap/kyml
Download a binary from the release page.
This downloads the latest version for Linux:
curl -sfL -o /usr/local/bin/kyml https://github.com/frigus02/kyml/releases/download/v20210610/kyml_20210610_linux_amd64 && chmod +x /usr/local/bin/kyml
kyml
provides commands for concatenating YAML files, testing and templating. Commands usually read manifests from stdin and print them to stdout. This allows you to build a pipeline of commands, which can end with a kubectl apply
to do the deployment.
kyml cat
- concatenate YAML fileskyml test
- ensure updates always happen to all environmentskyml tmpl
- inject dynamic valueskyml resolve
- resolve Docker images to their digestRun kyml --help
for details about the different commands.
For most of the examples in this readme we assume the following structure:
manifests
|- staging
| |- deployment.yaml
| |- ingress.yaml
| `- service.yaml
`- production
|- deployment.yaml
|- ingress.yaml
`- service.yaml
And some of them use this:
manifests
|- base
| |- ingress.yaml
| `- service.yaml
`- overlays
|- staging
| `- deployment.yaml
`- production
`- deployment.yaml
You can adapt these or use anything else, that makes sense for your application.
kyml cat
- concatenate YAML filesConcatenate your files and pipe them into kubectl apply
to deploy them. This does 2 things:
kyml cat
deduplicates them. Only the one specified last makes it into the output.kyml cat deployment.yaml namespace.yaml
) the namespace will appear first in the output. This makes sure your resources are created in the correct order.kyml cat manifests/production/* | kubectl apply -f -
kyml cat manifests/base/* manifests/overlays/production/* | kubectl apply -f -
kyml test
- ensure updates always happen to all environmentsTesting works by creating a diff between two environments and storing it in a snapshot file. The command compares the diff result to the snapshot and fails if it doesn't match.
kyml test
reads manifests of the main environment from stdin and files from the comparison environment are specified as arguments, similar to kyml cat
. If the snapshot matches, it prints the main environment manifests to stdout. This way you can include a test in your deployment command pipeline to make sure nothing gets deployed if the test fails.
kyml cat manifests/production/* |
kyml test manifests/staging/* \
--name-main production \
--name-comparison staging \
--snapshot-file tests/snapshot-production-vs-staging.diff |
kubectl apply -f -
kyml tmpl
- inject dynamic valuesUse templates (in the go template syntax) to inject dynamic values. To make sure values are escaped properly and this feature doesn't get misused you can only template string scalars. Example:
apiVersion: v1
kind: Namespace
metadata:
name: the-namespace
labels:
branch: "{{.TRAVIS_BRANCH}}"
kyml test
reads manifests from stdin and prints the result to stdout. Values are provided as command line options. Use --value key=value
for literal strings and --env ENV_VAR
for environment variables. These options can be repeated multiple times. The command fails if the manifests contain any template key, which is not specified on the command line.
kyml cat manifests/production/* |
kyml test manifests/staging/* \
--name-main production \
--name-comparison staging \
--snapshot-file tests/snapshot-production-vs-staging.diff |
kyml tmpl \
-v Greeting=hello \
-v ImageTag=$(git rev-parse --short HEAD) \
-e TRAVIS_BRANCH |
kubectl apply -f -
kyml resolve
- resolve Docker images to their digestIf you tag the same image multiple times (e.g. because you build every commit and tag images with the commit sha), you may want to resolve the tags to the image digest. This way Kubernetes only restarts your applications if the image content has changed.
kyml cat manifests/production/* |
kyml tmpl -v ImageTag=$(git rev-parse --short HEAD) |
kyml resolve |
kubectl apply -f -
Please see CONTRIBUTING.md.