Helm Multi-Values Plugin with Argo's CMP

Table of Contents

Introduction #

With the current version of Helm, it’s not possible to merge multiple values files. It will override the list from the preceding values file. While trying to solve this problem, I stumbled upon this custom plugin that can take a folder of values files and split them into individual files. This plugin is what I was looking for to solve my problem. Finally, I want to integrate this plugin into my ArgoCD instance.

You’ll need to perform the following steps:

Install Helm Plugin using InitContainer of the repo server.
The configuration management plugin installation entails two steps. First, create a ConfigMap of your CMP configuration, then configure the plugin via sidecar for the repo server. For additional details, see the ArgoCD documentation.
Finally, create an Argo Application to test the multi-values plugin.

Prerequisites #

Make sure you have access to the OpenShift cluster with cluster-admin privileges.
The OpenShift GitOps Operator must be installed and configured
It would help if you had some understanding of ArgoCD and Helm Charts.

Install Helm Plugin in repo server #

We’ll use the custom tooling methodology to add the helm multivalues plugin to the repo server. Update the ArgoCD operator CR to add an init container to the repo spec and volumes to install the helm plugin. We must also add Helm environment variables to override default data, config, and cache paths.

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apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: openshift-gitops
  namespace: openshift-gitops
spec:
  repo:
    volumes:
      - configMap:
          name: helm-multivalues-plugin
        name: helm-multivalues-plugin
      - name: helm-custom-config
        emptyDir: {}
    env:
      - name: HELM_CACHE_HOME
        value: /.config/helm/cache
      - name: HELM_CONFIG_HOME
        value: /.config/helm/cache
      - name: HELM_DATA_HOME
        value: /.config/helm/data
    initContainers:
      - name: install-helm-multivalues-plugin
        image: registry.redhat.io/openshift-gitops-1/argocd-rhel8@sha256:baec6d73a77b832df8131bac3c5a86dc405ef89f600e27a22f164ed3c72816db
        command: [sh, -c]
        args:
          - "helm plugin install https://github.com/nico-ulbricht/helm-multivalues"
        env:
          - name: HELM_CACHE_HOME
            value: /helm-custom-config/cache
          - name: HELM_CONFIG_HOME
            value: /helm-custom-config/cache
          - name: HELM_DATA_HOME
            value: /helm-custom-config/data
        volumeMounts:
          - mountPath: /helm-custom-config
            name: helm-custom-config
    volumeMounts:
      - mountPath: /.config/helm
        name: helm-custom-config

Configure Argo CMP #

Next, create a ConfigMap with the configuration for the plugin. The generate command under spec section runs in the Application source directory each time manifests need to generate output. As per the plugin documentation, we need to run the helm multivalues [ORIGINAL_COMMAND] -f [VALUES_FOLDER_PATH] [ORIGINAL_ARGS] to generate the output as a stdout

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apiVersion: v1
kind: ConfigMap
metadata:
  name: helm-multivalues-plugin
  namespace: openshift-gitops
data:
  plugin.yaml: |
    apiVersion: argoproj.io/v1alpha1
    kind: ConfigManagementPlugin
    metadata:
      name: helm-multivalues-plugin
    spec:
      generate:
        command: [sh, -c, 'helm multivalues template $ARGOCD_APP_NAME $ARGOCD_ENV_CHART_PATH --values $ARGOCD_ENV_VALUES_FILE -f $ARGOCD_ENV_VALUES_FOLDER']    

The next step is to add the sidecar to the ArgoCD operator CR.

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apiVersion: argoproj.io/v1alpha1
kind: ArgoCD
metadata:
  name: openshift-gitops
  namespace: openshift-gitops
spec:
  repo:
    sidecarContainers:
      - name: helm-multivalues-plugin
        command: [/var/run/argocd/argocd-cmp-server]
        image: registry.redhat.io/openshift-gitops-1/argocd-rhel8@sha256:baec6d73a77b832df8131bac3c5a86dc405ef89f600e27a22f164ed3c72816db
        env:
          - name: HELM_CACHE_HOME
            value: /.config/helm/cache
          - name: HELM_CONFIG_HOME
            value: /.config/helm/cache
          - name: HELM_DATA_HOME
            value: /.config/helm/data
        volumeMounts:
          - mountPath: /var/run/argocd
            name: var-files
          - mountPath: /home/argocd/cmp-server/plugins
            name: plugins
          - mountPath: /tmp
            name: tmp
          - mountPath: /home/argocd/cmp-server/config/plugin.yaml
            subPath: plugin.yaml
            name: helm-multivalues-plugin
          - mountPath: /.config/helm
            name: helm-custom-config
    volumes:
      - configMap:
          name: helm-multivalues-plugin
        name: helm-multivalues-plugin
      - name: helm-custom-config
        emptyDir: {}
    env:
      - name: HELM_CACHE_HOME
        value: /.config/helm/cache
      - name: HELM_CONFIG_HOME
        value: /.config/helm/cache
      - name: HELM_DATA_HOME
        value: /.config/helm/data
    initContainers:
      - name: install-helm-multivalues-plugin
        image: registry.redhat.io/openshift-gitops-1/argocd-rhel8@sha256:baec6d73a77b832df8131bac3c5a86dc405ef89f600e27a22f164ed3c72816db
        command: [sh, -c]
        args:
          - "helm plugin install https://github.com/nico-ulbricht/helm-multivalues"
        env:
          - name: HELM_CACHE_HOME
            value: /helm-custom-config/cache
          - name: HELM_CONFIG_HOME
            value: /helm-custom-config/cache
          - name: HELM_DATA_HOME
            value: /helm-custom-config/data
        volumeMounts:
          - mountPath: /helm-custom-config
            name: helm-custom-config
    volumeMounts:
      - mountPath: /.config/helm
        name: helm-custom-config

A few things to review:

The code snippet above uses an argocd image to mount the plugin we installed in the earlier step and plugin.yaml in the container using the ConfigMap we just created.
Other mounts from Argo CD are necessary, like /var/run/argocd (that contains the argocd-cmp-server command that needs to run) and /home/argocd/cmp-server/plugins.

Apply the changes; Operator will rollout a latest changes of the repo-server pod.

Argo Application to Validate #

Let’s set up an ArgoCD application to test the changes

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apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: tenant-gitops-config
  namespace: openshift-gitops
spec:
  destination:
    server: "https://kubernetes.default.svc"
  project: default
  source:
    path: .
    repoURL: "https://github.com/Vikaspogu/openshift-multicluster.git"
    targetRevision: main
    plugin:
      name: helm-multivalues-plugin
      env:
        - name: CHART_PATH
          value: helm/charts/tenant-gitops
        - name: VALUES_FOLDER
          value: kustomize/cluster-overlays/dev-acm/tenant-gitops-helm/apps
        - name: VALUES_FILE
          value: kustomize/cluster-overlays/dev-acm/tenant-gitops-helm/values.yaml
  syncPolicy:
    retry:
      backoff:
        duration: 120s
        factor: 3
        maxDuration: 10m0s
      limit: 10
    syncOptions:
      - SkipDryRunOnMissingResource=true
      - Validate=false
      - ApplyOutOfSyncOnly=true
      - RespectIgnoreDifferences=true
      - Prune=true

Alt text — Deployed Helm Chart Application

Success! The Config Management Plugin ran the commands in the generate section to render out the YAML and Argo CD applied that YAML to the destination cluster.

Resources #

Helm Chart Repository
Helm MultiValues Folder