In my everyday work I need to depend many applications for Kubernetes, most of which have Helm charts. However these Helm charts are not perfect and I need to customize them to fit my needs. To do that I use Kustomize tool. The problem with that approach is that I need to generate some output from Helm and then apply my customizations on top of that. And this is what this tool does :)
The tool was inspired by Replicated Ship project, which offers more features than mine, like a nice GUI and many more things. However I prefer to work with simple editor than a fancy GUI, and that's the reason I created ship-light.
Create new directory for the application, then create file /ship-light.conf/ inside it with the following contents (the sample uses cluster-autoscaler from stabe repo of Helm):
SHIP_REPO=https://github.com/helm/charts.git
SHIP_PATH=stable/cluster-autoscaler
Now, invoke /ship-light/ script:
ship-light
ship-light will:
- clone the repo if it doesn't exist
- create /values.yaml/ file based on default values from helm chart
- create new namespace based on name of the directory with helm chart (can be overriden with SHIP_NAMESPACE setting in ship-light.conf)
- save current commit id for repo in .ship-commit file
- create /kustomization.yaml/ file
- get helm dependencies and render helm chart to /rendered.yaml/ file
After first usage you can customize values inside /values.yaml/ to change settings of helm chart, you can add some patches or additional resources to /kustomization.yaml/ and then invoke ship-light command again to re-render everything.
ship-light saves commit of helm chart inside .ship-commit file. With current version, if you want to update helm chart to newer version simply delete .ship-commit file and run ship-light again.
| Name | Description | Required | Default value |
|---|---|---|---|
| SHIP_REPO | URL to repo with helm chart | Yes | None |
| SHIP_PATH | Path inside repo to the directory with helm chart | Yes | None |
| SHIP_NAMESPACE | Overrides default namespace created by ship-light | No | basename $SHIP_PATH |
| SHIP_RELEASE_NAME | Release name for helm chart (used by some charts) | No | basename $SHIP_PATH |
| SHIP_REPO_CLONE_DIR | Path to place a repository with clonned helm chart | No | repo |
| SHIP_DEFAULT_BRANCH | Default branch to checkout during initial clone | No | None |
For corner cases, like rendering templates with duplicate service account names (see Kong repo; one service account is for pre-hook, the other is for the controller itself) ship-light supports executing user-provided scripts at some stages of execution. It supports the following hook scripts:
- ship-light-prerender.sh - is executed just before rendering the output with helm templates
The hook scripts should be places in the same directory as ship-light.conf and have to be executable.