ArgoCD: Defining groups of applications using ApplicationSet generators: list

argocd kubernetes ApplicationSet

2 min read | by Jordi Prats

With ArgoCD's ApplicationSet controller we can automate the Application creation by automatically generate Argo CD Applications based on the ApplicationSet template.

Withing the ApplicationSet we can choose between several generators that can be used to create the Application instances

One of the possible generators is the list generator. With it we can specify a list of elements with as many attributes as we need that will be rendered using the spec.template. For example:

apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: pet2cattle-versions
  namespace: argocd
spec:
  generators:
  - list:
      elements:
      - target: 1.0.0
        instance: v1
      - target: 2.0.0
        instance: v2
  template:
    metadata:
      name: pet2cattle-{{ instance }}
    spec:
      project: default
      syncPolicy:
        automated:
          prune: true
          selfHeal: true
        syncOptions:
          - CreateNamespace=true
      source:
        repoURL: ssh://git@github.com:jordiprats/helm-pet2cattle.git
        path: .
        targetRevision: "{{ target }}"
        helm:
          values: |
            ingress:
              hosts:
                - "{{ instance }}.pet2cattle.com
      destination:
        server: https://kubernetes.default.svc
        namespace: pet2cattle

This is going to create the following two Applications:

apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: pet2cattle-v1
spec:
  project: default
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
      - CreateNamespace=true
  source:
    repoURL: ssh://git@github.com:jordiprats/helm-pet2cattle.git
    path: .
    targetRevision: "1.0.0"
    helm:
      values: |
        ingress:
          hosts:
            - "v1.pet2cattle.com"
  destination:
    server: https://kubernetes.default.svc
    namespace: pet2cattle
---
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: pet2cattle-v2
spec:
  project: default
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
      - CreateNamespace=true
  source:
    repoURL: ssh://git@github.com:jordiprats/helm-pet2cattle.git
    path: .
    targetRevision: "2.0.0"
    helm:
      values: |
        ingress:
          hosts:
            - "v2.pet2cattle.com"
  destination:
    server: https://kubernetes.default.svc
    namespace: pet2cattle

So, with this generator we can just add more elements to the list to automatically deploy a new application.

Posted on 08/06/2022

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