argocd-helm-ext-plugin

An Argo CD plugin to retrieve helm chart from remote helm repository and use values files and custom values on local git repository.

What can this plugin do?

• Set spec.source.repoURL to your-own git repository, which contains value files, and uses a helm chart on the remote Helm chart repository.
• Support multiple values YAML files for a better management experience.
• Set additional values by passing HELM_VALUES plugin environment variable via argocd app set <APP_NAME> --plugin-env "HELM_VALUES=key1=value1;key2=value2"

Why do you needs this plugin?

The current Argo CD (v2.4) does not support using a published helm chart on a remote repository and assigning custom value settings in files on another git repository (usually, it is your repo.) All the value files must be in the same repository as the Helm chart, which has some drawbacks.

• Need to write value settings in spec.source.helm.values. It is hard to write and maintain.
• Argo CD will not know when settings changed in the application YAML file because the repoURL points to the remote repository, so it needs to use app-of-apps pattern for bootstrapping and syncing the changes.

This plugin provides an alternative way to point to the same git repository URL containing helm value settings. Moreover, use the delicate value files to manage Helm chart settings.

Plugin environment variables

Name	Description
HELM_REPO_URL	The helm chart repository url, e.g.: https://charts.bitnami.com/bitnami
HELM_CHART	The helm chart name, e.g.: nginx
HELM_CHART_VERSION	The helm chart vesion, e.g.: 12.0.0
HELM_VALUE_FILES	The values files, space-separated, e.g.: values.yaml secrects.yaml
HELM_VALUES	The additional values, semicolon-separated, e.g: key1=values;key2=values

Installation

Please refer Argo CD Config Management Plugins Installation. It recommends to configure this plugin via Argo CD configmap.

argocd-cm ConfigMap example

apiVersion: v1
kind: ConfigMap
metadata:
  name: argocd-cm
data:
  configManagementPlugins: |-
    - name: argocd-helm-ext-plugin
      generate:
        command: ["argocd-helm-ext-plugin"]
        args: ["--include-crds"]

Configuration

Application CRD. configuration example

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: demo-app
  namespace: default
spec:
  project: default
  source:
    # the repository containing the helm value files
    repoURL: https://git.example.com/demo.git
    targetRevision: HEAD
    # the path of helm value files
    path: apps/demo-app

    # set argocd-helm-ext-plugin as plugin (the name is specified in argocd-cm config map)
    plugin:
      name: argocd-helm-ext-plugin
      env:
        # see the description in Plugin environment variables section
        - name: HELM_REPO_URL
          value: https://charts.bitnami.com/bitnami
        - name: HELM_CHART
          value: nginx
        - name: HELM_CHART_VERSION
          value: "12.0.5"
        - name: HELM_VALUE_FILES
          value: "values.yaml secrets.yaml"

  destination:
    server: https://kubernetes.default.svc
    namespace: default

Plugin arguments

Usage of argocd-helm-ext-plugin:
  -d, --debug        debug mode
  -c, --include-crds include custom resource
  -h, --help         prints help information

How to override helm values on the fly?

For some use cases, we need to specify some helm chart's values during deployment, e.g.: we might need to specify the image.tag to use specific image version. For this case we can set HELM_VALUES via Argo CD CLI.

Example:

# set image.tag and image.imagePullPolicy
argocd app set <APP_NAME> --plugin-env HELM_VALUES="image.tag=afeacb7;image.imagePullPolicy=Always"

# It's a argocd weird issue.,we need to hard refresh the application to invalidate manifest cache
# to make app. sync invokes plugin (tested on argocd v2.4.3)
argocd app get <APP_NAME> --hard-refresh

# start to sync app
argocd app sync <APP_NAME>