Argo CD: the app that refuses to sync

The situation

Welcome to platform engineering: from here on, nobody kubectl applys application manifests by hand. GitOps inverts the deploy arrow — instead of CI pushing YAML at the cluster, an in-cluster agent pulls the desired state from git and continuously reconciles toward it. Git becomes the database of intent (a very M7.1 idea: reconcile loops, one level up), and a deploy is a commit.

Argo CD is that agent here, freshly installed in the argocd namespace:

kubectl -n argocd get pods
# argocd-application-controller-0   ← the reconciler
# argocd-repo-server-…              ← clones repos, renders manifests
# argocd-server-…                   ← API/UI

One Application — Argo CD's CRD binding a git source to a cluster destination — is supposed to deploy the classic guestbook:

kubectl -n argocd get application guestbook
# NAME        SYNC STATUS   HEALTH STATUS
# guestbook   Unknown       Healthy

Unknown is not a phase to wait out. Ask why:

kubectl -n argocd get application guestbook -o jsonpath='{.status.conditions}' | python3 -m json.tool
# "type": "ComparisonError"
# "message": "… app path does not exist: apps/guestbook …"

The Application's spec.source.path says apps/guestbook; the repo's guestbook actually lives at guestbook. Argo CD can't render the desired state, so it can't even compare — sync status Unknown, forever, while the UI shows a comforting green Healthy for the zero resources it manages.

   ┌─────────┐    
   │git repo │    
   │         │    
   └─────────┘    
         │        
   desired state  
         │        
         ▼        
 ┌──────────────┐ 
 │Argo CD agent │ 
 │              │ 
 └──────────────┘ 
         │        
  continuous sync 
         │        
         ▼        
  ┌──────────────┐
  │cluster state │
  │              │
  └──────────────┘

Your task

1. Confirm the real path yourself — the repo is public: https://github.com/argoproj/argocd-example-apps, directory guestbook.
2. Fix the Application's source path:

   kubectl -n argocd patch application guestbook --type=merge \
     -p '{"spec":{"source":{"path":"guestbook"}}}'
   

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3. Auto-sync is on (syncPolicy.automated) — watch the machine do the rest:

   kubectl -n argocd get application guestbook -w
   # Unknown → OutOfSync → Synced   /   Healthy
   kubectl -n kubelings get deploy guestbook-ui
   

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kubectl -n argocd get app guestbook -o jsonpath='{.status.conditions}'      # can it compare?
kubectl -n argocd get app guestbook -o jsonpath='{.status.sync.status}'     # does live match git?
kubectl -n argocd get app guestbook -o jsonpath='{.status.health.status}'   # is the workload up?

kubectl -n argocd patch application guestbook --type=merge \
  -p '{"spec":{"source":{"path":"guestbook"}}}'
kubectl -n argocd get application guestbook -w   # → Synced / Healthy