Flux - CLI-Focused GitOps

Flux is a lightweight, modular GitOps tool designed for platform engineers who prefer CLI-based automation.

Overview

Flux provides:

• CLI-First - Manage via command line
• Modular Architecture - Small, focused controllers
• Lightweight - Minimal resource overhead
• Native Kubernetes - Feels like native K8s resources
• Headless - No UI, pure automation

Installation

Using Flux CLI

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

# Bootstrap Flux
flux bootstrap github \
  --owner=your-org \
  --repository=your-repo \
  --branch=main \
  --path=./clusters/my-cluster \
  --personal

Using Helm

helm repo add fluxcd https://fluxcd-community.github.io/helm-charts
helm repo update

helm install flux fluxcd/flux2 \
  --namespace flux-system \
  --create-namespace

GitRepository Resource

Defines the Git source to watch:

apiVersion: source.toolkit.fluxcd.io/v1beta2
kind: GitRepository
metadata:
  name: sample-app
  namespace: flux-system
spec:
  interval: 1m
  url: https://github.com/your-org/your-repo
  ref:
    branch: main
  secretRef:
    name: git-credentials

Kustomization Resource

Defines what to deploy from the Git repository:

apiVersion: kustomize.toolkit.fluxcd.io/v1beta2
kind: Kustomization
metadata:
  name: sample-app
  namespace: flux-system
spec:
  interval: 5m
  path: ./kustomize/overlays/staging
  prune: true
  sourceRef:
    kind: GitRepository
    name: sample-app
  targetNamespace: staging
  healthChecks:
    - apiVersion: apps/v1
      kind: Deployment
      name: sample-app
      namespace: staging

Usage

Create Resources

kubectl apply -f flux/gitrepository.yaml
kubectl apply -f flux/kustomization.yaml

Check Status

# Check GitRepository
flux get sources git

# Check Kustomization
flux get kustomizations

# Check all Flux resources
flux get all

Reconcile

# Trigger reconciliation
flux reconcile source git sample-app
flux reconcile kustomization sample-app

View Logs

# Source controller logs
kubectl logs -n flux-system -l app=source-controller

# Kustomize controller logs
kubectl logs -n flux-system -l app=kustomize-controller

Best Practices

1. Use short intervals for staging (1-5 minutes)
2. Use longer intervals for production (15-30 minutes)
3. Enable pruning to remove deleted resources
4. Use health checks to verify deployments

Additional Resources

• Flux Documentation
• Flux CLI Reference