Is it possible to use sync-wave for app?

[dmitry-mightydevops]

Guys,

Is it possible to have a sync-wave control for apps using app of apps pattern?
https://argoproj.github.io/argo-cd/user-guide/sync-waves/

something like this, so we can have a sync order between the apps (i.e. app1, then app2 etc).

# helm show values grafana/grafana
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: ingress-nginx
  annotations:
    argocd.argoproj.io/sync-wave: "1"
  finalizers:
  - resources-finalizer.argocd.argoproj.io
spec:
  destination:
    server: https://kubernetes.default.svc
    namespace: ingress-nginx
  project: default
  source:
    chart: ingress-nginx
    helm:
      values: |
        controller:
          config:
            use-http2: "true"
          nodeSelector:
            ops: "true"
          service:
            annotations:
              external-dns.alpha.kubernetes.io/hostname: domain.com
              service.beta.kubernetes.io/aws-load-balancer-backend-protocol: tcp
              service.beta.kubernetes.io/aws-load-balancer-cross-zone-load-balancing-enabled: "true"
              service.beta.kubernetes.io/aws-load-balancer-type: nlb
        
          metrics:
            enabled: true
          podLabels: 
            app: "ingress-nginx"

    repoURL: https://kubernetes.github.io/ingress-nginx
    targetRevision: 3.33.0
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
      - CreateNamespace=true

[jannfis]

Hey @dmitry-mightydevops, the short answer to this is, "it depends".

The long answer is, sync-waves apply to any given running sync operation. So, if you have an app-of-apps (let's call it parent) that spawns multiple child apps (let's call them child1, child2 and child3 here), and the child apps have a sync-wave annotation on the Application resource, the sync-waves apply only during sync of parent.

They will not apply upon sync of the child apps, so if all three child apps are out of sync, and auto-sync is enabled, they will just sync in any order as deemed right by the application controller.

So if your use-case is to sync those apps in a specific order at bootstrap time (e.g. when they're initially created), this will work fine. You sync the parent app into the cluster, and the child1 through child3 will be created (and synced) according to their sync-waves. But as said, this will only happen when the parent app actually syncs. Furthermore, for Argo CD v1.8 and upwards, you will need to explicitly configure a health check for Application resources in order to make this work.