FluxCD Interview Q&A

Q: FluxCD vs ArgoCD?

Both are CNCF GitOps tools. FluxCD: more Kubernetes-native, composable toolkit (Flux controllers), better multi-tenancy. ArgoCD: better UI, application-centric view, richer health checks. Choice depends on team preference — both solve GitOps.

Q: What is Flux's image automation?

Image Reflector Controller scans container registry for new tags. Image Automation Controller writes new tag to Git. Flux then deploys updated image automatically. Fully GitOps — no webhooks needed.

Q: How does Flux handle multi-tenancy?

Each team gets a Kustomization pointing to their namespace. Network policies + RBAC restrict cross-namespace access. Flux runs per-namespace service accounts with least privilege.

Q: What is the GitOps reconciliation loop?

Flux constantly compares desired state (Git) with actual state (cluster). On divergence, it applies the difference. Default interval: 1-5 minutes. Manual sync: flux reconcile kustomization myapp.

Q: How does Flux handle secret management?

Flux does not manage secrets directly. Use: SOPS (encrypt secrets in Git with age/PGP keys), Sealed Secrets (Kubeseal encrypts, cluster decrypts), or External Secrets Operator (fetch from Vault/AWS SM at runtime). Never commit plaintext secrets to GitOps repo.

Q: What is a Flux Kustomization vs Kubernetes Kustomize?

They are different: Kubernetes Kustomize is the kubectl native tool for customising manifests. Flux Kustomization (capital K) is a Flux CRD that watches a Git source and applies manifests. Flux uses Kustomize under the hood but adds health checks, dependency ordering, and automatic sync.

Q: How do you roll back with Flux?

Revert the Git commit — Flux will detect the change and apply the previous state. Unlike ArgoCD's rollback command, Flux rollback is always done via Git history. This maintains the GitOps principle: Git is the single source of truth.