Fix ArgoCD Application Stuck in OutOfSync

The Problem

Your ArgoCD application is permanently stuck in OutOfSync status regardless of how many times you sync.

Root Cause

This is different from a temporary sync issue. The application is stuck because:

1. Mutating admission webhooks change resources after deployment
2. Kubernetes defaulting adds fields not in your manifests
3. Another controller (HPA, Istio, Kyverno) modifies the resource

Fix

Step 1: Find the Diff

argocd app diff my-app

Step 2: Add ignoreDifferences

spec:
  ignoreDifferences:
    - group: apps
      kind: Deployment
      jsonPointers:
        - /spec/replicas
    - group: networking.istio.io
      kind: VirtualService
      jqPathExpressions:
        - .metadata.generation

Step 3: Use Server-Side Apply

spec:
  syncPolicy:
    syncOptions:
      - ServerSideApply=true

Server-side apply lets Kubernetes handle field ownership conflicts, often resolving persistent OutOfSync issues.

Related Resources

• ArgoCD Cheat Sheet
• Fix ArgoCD SyncError Application Out of Sync