Gitops Workflow

# GitOps Workflow

Complete guide to implementing GitOps workflows with ArgoCD and Flux for automated Kubernetes deployments.

## Purpose

Implement declarative, Git-based continuous delivery for Kubernetes using ArgoCD or Flux CD, following OpenGitOps principles.

## When to Use This Skill

- Set up GitOps for Kubernetes clusters
- Automate application deployments from Git
- Implement progressive delivery strategies
- Manage multi-cluster deployments
- Configure automated sync policies
- Set up secret management in GitOps

## OpenGitOps Principles

1. **Declarative** - Entire system described declaratively
2. **Versioned and Immutable** - Desired state stored in Git
3. **Pulled Automatically** - Software agents pull desired state
4. **Continuously Reconciled** - Agents reconcile actual vs desired state

## ArgoCD Setup

### 1. Installation

```bash
# Create namespace
kubectl create namespace argocd

# Install ArgoCD
kubectl apply -n argocd -f https://raw.githubusercontent.com/argoproj/argo-cd/stable/manifests/install.yaml

# Get admin password
kubectl -n argocd get secret argocd-initial-admin-secret -o jsonpath="{.data.password}" | base64 -d
```

**Reference:** See `references/argocd-setup.md` for detailed setup

### 2. Repository Structure

```
gitops-repo/
├── apps/
│   ├── production/
│   │   ├── app1/
│   │   │   ├── kustomization.yaml
│   │   │   └── deployment.yaml
│   │   └── app2/
│   └── staging/
├── infrastructure/
│   ├── ingress-nginx/
│   ├── cert-manager/
│   └── monitoring/
└── argocd/
    ├── applications/
    └── projects/
```

### 3. Create Application

```yaml
# argocd/applications/my-app.yaml
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: my-app
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/org/gitops-repo
    targetRevision: main
    path: apps/production/my-app
  destination:
    server: https://kubernetes.default.svc
    namespace: production
  syncPolicy:
    automated:
      prune: true
      selfHeal: true
    syncOptions:
      - CreateNamespace=true
```

### 4. App of Apps Pattern

```yaml
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: applications
  namespace: argocd
spec:
  project: default
  source:
    repoURL: https://github.com/org/gitops-repo
    targetRevision: main
    path: argocd/applications
  destination:
    server: https://kubernetes.default.svc
    namespace: argocd
  syncPolicy:
    automated: {}
```

## Flux CD Setup

### 1. Installation

```bash
# Install Flux CLI
curl -s https://fluxcd.io/install.sh | sudo bash

# Bootstrap Flux
flux bootstrap github \
  --owner=org \
  --repository=gitops-repo \
  --branch=main \
  --path=clusters/production \
  --personal
```

### 2. Create GitRepository

```yaml
apiVersion: source.toolkit.fluxcd.io/v1
kind: GitRepository
metadata:
  name: my-app
  namespace: flux-system
spec:
  interval: 1m
  url: https://github.com/org/my-app
  ref:
    branch: main
```

### 3. Create Kustomization

```yaml
apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
  name: my-app
  namespace: flux-system
spec:
  interval: 5m
  path: ./deploy
  prune: true
  sourceRef:
    kind: GitRepository
    name: my-app
```

## Sync Policies

### Auto-Sync Configuration

**ArgoCD:**

```yaml
syncPolicy:
  automated:
    prune: true # Delete resources not in Git
    selfHeal: true # Reconcile manual changes
    allowEmpty: false
  retry:
    limit: 5
    backoff:
      duration: 5s
      factor: 2
      maxDuration: 3m
```

**Flux:**

```yaml
spec:
  interval: 1m
  prune: true
  wait: true
  timeout: 5m
```

**Reference:** See `references/sync-policies.md`

## Progressive Delivery

### Canary Deployment with ArgoCD Rollouts

```yaml
apiVersion: argoproj.io/v1alpha1
kind: Rollout
metadata:
  name: my-app
spec:
  replicas: 5
  strategy:
    canary:
      steps:
        - setWeight: 20
        - pause: { duration: 1m }
        - setWeight: 50
        - pause: { duration: 2m }
        - setWeight: 100
```

### Blue-Green Deployment

```yaml
strategy:
  blueGreen:
    activeService: my-app
    previewService: my-app-preview
    autoPromotionEnabled: false
```

## Secret Management

### External Secrets Operator

```yaml
apiVersion: external-secrets.io/v1beta1
kind: ExternalSecret
metadata:
  name: db-credentials
spec:
  refreshInterval: 1h
  secretStoreRef:
    name: aws-secrets-manager
    kind: SecretStore
  target:
    name: db-credentials
  data:
    - secretKey: password
      remoteRef:
        key: prod/db/password
```

### Sealed Secrets

```bash
# Encrypt secret
kubeseal --format yaml < secret.yaml > sealed-secret.yaml

# Commit sealed-secret.yaml to Git
```

## Best Practices

1. **Use separate repos or branches** for different environments
2. **Implement RBAC** for Git repositories
3. **Enable notifications** for sync failures
4. **Use health checks** for custom resources
5. **Implement approval gates** for production
6. **Keep secrets out of Git** (use External Secrets)
7. **Use App of Apps pattern** for organization
8. **Tag releases** for easy rollback
9. **Monitor sync status** with alerts
10. **Test changes** in staging first

## Troubleshooting

**Sync failures:**

```bash
argocd app get my-app
argocd app sync my-app --prune
```

**Out of sync status:**

```bash
argocd app diff my-app
argocd app sync my-app --force
```

## Related Skills

- `k8s-manifest-generator` - For creating manifests
- `helm-chart-scaffolding` - For packaging applications