2766 Diffmanifests 393c7066

DiffManifests Workflow

Compare live cluster state against desired state in Git.

When to Use

• Understanding why an app is OutOfSync
• Reviewing what changes will be applied during sync
• Detecting configuration drift
• Validating changes before deployment

Workflow Steps

Step 1: Basic Diff

# Show diff between live and desired state
argocd app diff <app-name>

Output shows:

• === Lines that match
• --- Lines only in live (will be removed)
• +++ Lines only in desired (will be added)

Step 2: Diff with Local Changes (Pre-commit Review)

# For Helm/Kustomize apps (server-side generation)
argocd app diff <app-name> --local <repo-root> --server-side-generate

# For plain manifests
argocd app diff <app-name> --local <path-to-manifests>

Step 3: Review Specific Resources

# Get live manifest for specific resource
argocd app manifests <app-name> --source live | grep -A 50 "kind: Deployment"

# Get desired manifest
argocd app manifests <app-name> | grep -A 50 "kind: Deployment"

Step 4: Check Ignored Differences

Some differences may be intentionally ignored:

# View ignoreDifferences configuration
argocd app get <app-name> -o json | jq '.spec.ignoreDifferences'

Common Diff Scenarios

Scenario: Immutable Field Changes

# Error: cannot change immutable field
# Solution: May need to delete and recreate resource
argocd app sync <app-name> --replace --resource <group>:<kind>:<name>

Scenario: Cluster-Generated Fields

Fields like metadata.resourceVersion, status, metadata.uid are cluster-managed. These should be in ignoreDifferences:

spec:
  ignoreDifferences:
    - group: apps
      kind: Deployment
      jsonPointers:
        - /spec/replicas  # If using HPA

Verifying Changes Before Sync

# Dry-run to see what would happen
argocd app sync <app-name> --dry-run

# Then actual sync if satisfied
argocd app sync <app-name>