Auto-update helm chart version using ArgoCD

Having had experience with Kubernetes for a few years, I’ve grown to appreciate the convenience of deploying and updating applications with Helm charts. In this article, my goal is to guide you on how to take this process a step further by automating the update procedure for Helm applications using ArgoCD. To illustrate, I will be using a Robusta Helm installation as an example.

ArgoCD is an open-source tool for automating and managing the deployment of applications to Kubernetes clusters, using GitOps principles. It provides a declarative approach to defining and maintaining the desired state of an application in a Kubernetes environment.

Robusta is an open-source application that is capable of monitoring and visualizing Kubernetes clusters. It provides metrics for monitoring cluster health and Kubernetes events and it integrates seamlessly with Prometheus.

Requirements

• kubectl command-line tool
• chocolatey/brew package manager
• jq command-line JSON processor
• pip Python package installer

Step 1 — Install ArgoCD and ArgoCD CLI
There are two ways to accomplish this task — you can either refer to the Getting Started section in the official ArgoCD documentation or make use of the following commands:

kubectl create namespace argocd
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml
choco install argocd-cli

Step 2 —Login to ArgoCD
Upon ArgoCD installation, an admin password secret is automatically generated. This secret is named argocd-initial-admin-secret and can be decoded by executing the following command:

kubectl get secret -n argocd argocd-initial-admin-secret -o json | jq .data.password -r | base64 -d

There are a couple of ways to access the ArgoCD UI — you can modify the service type of the argocd-server to LoadBalancer and set up an ingress. Further information on how to perform these actions can be found in the “Getting Started” article. However, for now, we will stick to using kubectl port-forwarding:

kubectl port-forward svc/argocd-server -n argocd 8080:443
The ArgoCD server can be accessed at https://localhost:8080

To login using the CLI you’ll have to execute the command below using the admin username and the password decoded above.
argocd login <ARGOCD-SERVER>

Step 3 — Install Robusta CLI and generate Helm values
To generate the helm values for the installation of Robusta, this step is necessary. The installation guide provides a quick way on setting up Robusta using Helm, but these instructions need to be slightly adjusted for ArgoCD to enable automatic updates. This approach proved helpful to me in a multi-cluster environment where manual updates would cause unnecessary delays.

pip install -U robusta-cli --no-cache
robusta gen-config

Upon completion, a generated_values.yaml file will be created. This file includes the helm values that are necessary for deploying Robusta with ArgoCD in Step 5.

Step 4 — Connect Robusta Helm repository to ArgoCD
You have the option to perform this task using either ArgoCD UI or CLI. If you choose to use CLI, the command below can be used:

argocd repo add https://robusta-charts.storage.googleapis.com --type helm --name robusta

Step 5 —Deploy ArgoCD helm chart application
To deploy the ArgoCD application with the helm values, I will use the declarative approach, but you can achieve the same outcome using ArgoCD UI. To begin, you must build your application in a YAML manifest file called robusta-app.yaml, as shown in the example below:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: robusta
  namespace: argocd
spec:
  destination:
    namespace: robusta
    server: 'https://kubernetes.default.svc'
  source:
    repoURL: 'https://robusta-charts.storage.googleapis.com'
    targetRevision: 0.10.12
    chart: robusta
    helm:
      values: |
        globalConfig:
          signing_key: <signing_key_from_generated_values.yaml>
          account_id: <account_id_from_generated_values.yaml>
        sinksConfig:
        - robusta_sink:
            name: robusta_ui_sink
            token: <token_from_generated_values.yaml>
        enablePlatformPlaybooks: true
        runner:
          sendAdditionalTelemetry: true
        rsa:
          private: <private_from_generated_values>
          public: <public_from_generated_values>
      parameters:
        - name: clusterName
          value: demo_cluster
  sources: []
  project: default
  syncPolicy:
    automated:
      prune: false
      selfHeal: false
    syncOptions:
      - CreateNamespace=true

Once you create the application running kubectl apply -f robusta-app.yaml, you'll notice the application has been created in ArgoCD UI with Target Revision: 0.10.12

Step 6— Auto-update helm chart version using ArgoCD
Although we have specified Automatic as the SyncPolicy, we will not receive automatic updates when new releases become available. The current Robusta application will only synchronize and update if there are changes made to chart version 0.10.12, which is unlikely to happen in a Helm environment. Even if there are bugs that need to be fixed in 0.10.12, the fixes will likely be released in a new Helm chart version (e.g., 0.10.13). Because we have set the Target Revision to 0.10.12, we will not receive automatic updates for those bugfixes.

To address this issue, we will be using a wildcard (*), changing the Target Revision to 0.10.*, which will ensure that we receive automatic updates for all patches of version 0.10.*. When a Helm chart with version 0.10.13 is released, the application will automatically be updated, as shown in the example below, eliminating the need for any manual intervention in your CD pipeline.

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: robusta
  namespace: argocd
spec:
  destination:
    namespace: robusta
    server: 'https://kubernetes.default.svc'
  source:
    repoURL: 'https://robusta-charts.storage.googleapis.com'
    targetRevision: 0.10.*

One can apply a comparable approach to automatically update both the minor version and patch version by going a step further. For instance, if the Robusta application is first deployed with a Target Revision of 0.9.17 and subsequently changed to 0.*.*, the helm chart version will be updated by ArgoCD to the most recent minor version of the specified major version (in this case - 0), which at the time of writing this article is 0.10.13. This can be seen in the two screenshots provided below.

I hope these instructions will help keep your Helm applications up to date. If you have any questions and would like to connect with me on a specific subject, please feel free to use the comment section on Medium or add me to your LinkedIn network. I’d be happy to chat and keep in touch!

References:
1. https://argo-cd.readthedocs.io/en/stable/getting_started/
2. https://docs.robusta.dev/master/installation.html