render-helm-chart
render-helm-chart #
Overview #
The render-helm-chart function renders a local or remote Helm chart.
Helm is a package manager for kubernetes that uses a packaging format called charts. A chart is a collection of files within a directory, which contain templates, CRDs, values, and metadata.
This function renders charts by using the helm template command, so that helm charts can be rendered without needing to install the helm binary directly.
You can learn more about helm here and more about helm charts here.
Usage #
This function can be used with any KRM function orchestrators such as kpt or kustomize to render a specified helm chart.
In kpt, the function can only be run imperatively. The function either
needs network access to render a remote chart or needs a local file to be mounted
into the container to render a local chart. As a result, to run the
function with kpt fn eval, the flag --network must be used for remote charts,
and the flag --mount must be used for local charts. See the examples for inflating
local and
remote charts.
It can be used declaratively when run with kustomize. To run the function with kustomize,
the network field is needed for remote charts and the mounts field is needed for local charts.
FunctionConfig #
There are 2 kinds of functionConfig supported by this function:
ConfigMap- A custom resource of kind
RenderHelmChart
<code>ConfigMap</code> #
To use a ConfigMap as the functionConfig, the desired parameters must be
specified in the data field:
data:
chartHome: string
configHome: string
name: string
version: string
repo: string
releaseName: string
namespace: string
valuesFile: string
includeCRDs: string
| Field | Description | Example |
|---|---|---|
chartHome | A filepath to a directory of charts. The function will look for the chart in this local directory before attempting to pull the chart from a specified repo. Defaults to “tmp/charts”. When run in a container, this path MUST have the prefix “tmp/”. | tmp/charts |
configHome | Defines a value that the function should pass to helm via the HELM_CONFIG_HOME environment variable. If omitted, {tmpDir}/helm is used, where {tmpDir} is some temporary directory created by the function for the benefit of helm. This option is not supported when running in a container. It is supported only in exec mode (e.g. with kustomize) | /tmp/helm/config |
name | The name of the chart | minecraft |
version | The version of the chart | 3.1.3 |
repo | A URL locating the chart on the internet | https://itzg.github.io/minecraft-server-charts |
releaseName | Replaces RELEASE_NAME in the chart template output | test |
namespace | Sets the target namespace for a release (.Release.Namespace in the template) | my-namespace |
valuesFile | valuesFile is a remote or local file path to a values file to use instead of the default values that accompanied the chart. The default values are in ‘{chartHome}/{name}/values.yaml’, where chartHome and name are the parameters defined above. | Using a local values file: path/to/your/values.yaml Using a remote values file: https://raw.githubusercontent.com/config-sync-examples/helm-components/main/cert-manager-values.yaml |
includeCRDs | Specifies if Helm should also generate CustomResourceDefinitions. Legal values: “true”, “false” (default). | “true” |
The only required field is name.
<code>RenderHelmChart</code> #
A functionConfig of kind RenderHelmChart has the following supported parameters:
helmGlobals:
chartHome: string
configHome: string
helmCharts:
- name: string
version: string
repo: string
releaseName: string
namespace: string
valuesInline: map[string]interface{}
valuesFile: string
valuesMerge: string
includeCRDs: bool
| Field | Description | Example |
|---|---|---|
helmGlobals | Parameters applied to all Helm charts | |
helmCharts | An array of helm chart parameters | |
chartHome | A filepath to a directory of charts. The function will look for the chart in this local directory before attempting to pull the chart from a specified repo. Defaults to “tmp/charts”. When run in a container, this path MUST have the prefix “tmp/”. | tmp/charts |
configHome | Defines a value that the function should pass to helm via the HELM_CONFIG_HOME environment variable. If omitted, {tmpDir}/helm is used, where {tmpDir} is some temporary directory created by the function for the benefit of helm. This option is not supported when running in a container. It is supported only in exec mode (e.g. with kustomize) | /tmp/helm/config |
name | The name of the chart | minecraft |
version | The version of the chart | 3.1.3 |
repo | A URL locating the chart on the internet | https://itzg.github.io/minecraft-server-charts |
releaseName | Replaces RELEASE_NAME in the chart template output | test |
namespace | Sets the target namespace for a release (.Release.Namespace in the template) | my-namespace |
valuesInline | Values to use instead of default values that accompany the chart | global: enabled: false tests: enabled: false |
valuesFile | valuesFile is a remote or local file path to a values file to use instead of the default values that accompanied the chart. The default values are in ‘{chartHome}/{name}/values.yaml’, where chartHome and name are the parameters defined above. | Using a local values file: path/to/your/values.yaml Using a remote values file: https://raw.githubusercontent.com/config-sync-examples/helm-components/main/cert-manager-values.yaml |
valuesMerge | ValuesMerge specifies how to treat ValuesInline with respect to Values. Legal values: ‘merge’, ‘override’ (default), ‘replace’. | replace |
includeCRDs | Specifies if Helm should also generate CustomResourceDefinitions. Defaults to false. | true |
The only required field is name.
Examples #
To render a remote minecraft chart, you can run the following command:
$ kpt fn eval --image gcr.io/kpt-fn/render-helm-chart:v0.1.0 --network -- \
name=minecraft \
repo=https://itzg.github.io/minecraft-server-charts \
releaseName=test
The key-value pairs after the -- will be converted to a functionConfig of kind
ConfigMap. The above command will add two files to your directory, which you can view:
$ kpt pkg tree
├── [secret_test-minecraft.yaml] Secret test-minecraft
└── [service_test-minecraft.yaml] Service test-minecraft