liauw-media/gitops-workflows

GitOps Workflows

Git as the single source of truth for declarative infrastructure and applications.

When to Use

• Implementing continuous deployment to Kubernetes
• Managing infrastructure changes through Git
• Setting up ArgoCD or Flux
• Designing promotion workflows (dev → staging → prod)
• Implementing drift detection and remediation

Core Principles

| Principle | Description | |-----------|-------------| | Declarative | Desired state described in Git | | Versioned | Full history of changes | | Automated | Changes applied automatically | | Auditable | Git commits = audit trail |

Repository Structure

Monorepo Pattern

gitops-repo/
├── apps/
│   ├── base/                    # Base manifests
│   │   └── myapp/
│   │       ├── deployment.yaml
│   │       ├── service.yaml
│   │       └── kustomization.yaml
│   └── overlays/
│       ├── development/
│       │   └── kustomization.yaml
│       ├── staging/
│       │   └── kustomization.yaml
│       └── production/
│           └── kustomization.yaml
│
├── infrastructure/
│   ├── base/
│   │   ├── cert-manager/
│   │   ├── ingress-nginx/
│   │   └── monitoring/
│   └── overlays/
│       └── production/
│
└── clusters/
    ├── development/
    │   └── apps.yaml            # ArgoCD Application
    ├── staging/
    └── production/

ArgoCD

Installation

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

Application Definition

# clusters/production/myapp.yaml
apiVersion: argoproj.io/v1alpha1
kind: Application
metadata:
  name: myapp
  namespace: argocd
  finalizers:
    - resources-finalizer.argocd.argoproj.io
spec:
  project: default

  source:
    repoURL: https://github.com/org/gitops-repo.git
    targetRevision: main
    path: apps/overlays/production

  destination:
    server: https://kubernetes.default.svc
    namespace: myapp

  syncPolicy:
    automated:
      prune: true
      selfHeal: true
      allowEmpty: false
    syncOptions:
      - CreateNamespace=true
      - PrunePropagationPolicy=foreground
      - PruneLast=true
    retry:
      limit: 5
      backoff:
        duration: 5s
        factor: 2
        maxDuration: 3m

  # Health checks
  ignoreDifferences:
    - group: apps
      kind: Deployment
      jsonPointers:
        - /spec/replicas  # Ignore HPA changes

ApplicationSet (Multi-Environment)

apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: myapp
  namespace: argocd
spec:
  generators:
    - list:
        elements:
          - cluster: development
            url: https://dev-cluster.example.com
          - cluster: staging
            url: https://staging-cluster.example.com
          - cluster: production
            url: https://prod-cluster.example.com

  template:
    metadata:
      name: 'myapp-{{cluster}}'
    spec:
      project: default
      source:
        repoURL: https://github.com/org/gitops-repo.git
        targetRevision: main
        path: 'apps/overlays/{{cluster}}'
      destination:
        server: '{{url}}'
        namespace: myapp
      syncPolicy:
        automated:
          prune: true
          selfHeal: true

Flux

Installation

flux bootstrap github \
  --owner=my-org \
  --repository=gitops-repo \
  --branch=main \
  --path=clusters/production \
  --personal

GitRepository Source

apiVersion: source.toolkit.fluxcd.io/v1
kind: GitRepository
metadata:
  name: gitops-repo
  namespace: flux-system
spec:
  interval: 1m
  url: https://github.com/org/gitops-repo
  ref:
    branch: main
  secretRef:
    name: github-token

Kustomization

apiVersion: kustomize.toolkit.fluxcd.io/v1
kind: Kustomization
metadata:
  name: myapp
  namespace: flux-system
spec:
  interval: 10m
  targetNamespace: myapp
  sourceRef:
    kind: GitRepository
    name: gitops-repo
  path: ./apps/overlays/production
  prune: true
  healthChecks:
    - apiVersion: apps/v1
      kind: Deployment
      name: myapp
      namespace: myapp
  timeout: 2m

HelmRelease

apiVersion: helm.toolkit.fluxcd.io/v2beta1
kind: HelmRelease
metadata:
  name: myapp
  namespace: myapp
spec:
  interval: 5m
  chart:
    spec:
      chart: myapp
      version: "1.x"
      sourceRef:
        kind: HelmRepository
        name: myrepo
        namespace: flux-system
  values:
    replicas: 3
    image:
      tag: v1.0.0
  valuesFrom:
    - kind: ConfigMap
      name: myapp-values

Promotion Strategies

Environment Promotion

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│ Development │────▶│   Staging   │────▶│ Production  │
│             │     │             │     │             │
│  Auto-sync  │     │  Auto-sync  │     │ Manual/Gate │
│  on commit  │     │  on merge   │     │  approval   │
└─────────────┘     └─────────────┘     └─────────────┘

Image Update Automation (Flux)

apiVersion: image.toolkit.fluxcd.io/v1beta1
kind: ImageRepository
metadata:
  name: myapp
  namespace: flux-system
spec:
  image: registry.example.com/myapp
  interval: 1m
---
apiVersion: image.toolkit.fluxcd.io/v1beta1
kind: ImagePolicy
metadata:
  name: myapp
  namespace: flux-system
spec:
  imageRepositoryRef:
    name: myapp
  policy:
    semver:
      range: 1.x
---
apiVersion: image.toolkit.fluxcd.io/v1beta1
kind: ImageUpdateAutomation
metadata:
  name: myapp
  namespace: flux-system
spec:
  interval: 1m
  sourceRef:
    kind: GitRepository
    name: gitops-repo
  git:
    checkout:
      ref:
        branch: main
    commit:
      author:
        email: [email protected]
        name: Flux
      messageTemplate: 'Update {{.AutomationObject.Name}} to {{.NewVersion}}'
    push:
      branch: main
  update:
    path: ./apps/overlays/production
    strategy: Setters

Kustomize Overlays

Base Deployment

# apps/base/myapp/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: 1
  selector:
    matchLabels:
      app: myapp
  template:
    metadata:
      labels:
        app: myapp
    spec:
      containers:
        - name: myapp
          image: myapp:latest
          ports:
            - containerPort: 8080
          resources:
            requests:
              cpu: 100m
              memory: 128Mi

Production Overlay

# apps/overlays/production/kustomization.yaml
apiVersion: kustomize.config.k8s.io/v1beta1
kind: Kustomization
namespace: myapp-prod

resources:
  - ../../base/myapp

replicas:
  - name: myapp
    count: 5

images:
  - name: myapp
    newTag: v1.2.3

patches:
  - patch: |-
      - op: replace
        path: /spec/template/spec/containers/0/resources
        value:
          requests:
            cpu: 500m
            memory: 512Mi
          limits:
            cpu: 1000m
            memory: 1Gi
    target:
      kind: Deployment
      name: myapp

configMapGenerator:
  - name: myapp-config
    literals:
      - LOG_LEVEL=info
      - ENV=production

Best Practices

1. Separate app and infra repos for different change velocities
2. Use sealed-secrets or external-secrets for secrets in Git
3. Implement branch protection on GitOps repos
4. Use PR reviews for production changes
5. Set up notifications for sync failures
6. Implement rollback procedures via Git revert

Troubleshooting

# ArgoCD
argocd app list
argocd app get myapp
argocd app sync myapp
argocd app history myapp
argocd app rollback myapp <revision>

# Flux
flux get all
flux reconcile kustomization myapp
flux logs --follow
flux events

Integration

Works with:

• /k8s - Kubernetes manifests
• /terraform - Infrastructure provisioning
• /devops - CI/CD pipelines
• policy-as-code skill - Pre-commit validation