Keyboard shortcuts

Press ← or → to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

0005. Deploy on Kubernetes behind Traefik

  • Status: Accepted
  • Date: 2026-06-22

Context

The app must run as several load-balanced replicas, scale with load, and be reachable over HTTPS on a domain. We target a single, modest VPS for the demo but want a setup that also works on a real cluster.

Decision

Deploy on Kubernetes, using k3s on the VPS (it bundles Traefik). Traefik is the ingress / load balancer that round-robins requests across the app pods via a Service; a HorizontalPodAutoscaler adds replicas under load. HTTPS is issued automatically by Traefik’s ACME (Let’s Encrypt) resolver. Manifests live in k8s/, and an Argo CD Application is provided for GitOps delivery.

Consequences

Positive

  • Real load balancing, autoscaling, self-healing, and rolling updates for free.
  • Same manifests work on k3s and on a full cluster.
  • Automatic, renewing TLS certificates.

Trade-offs / negative

  • Kubernetes adds operational complexity for what is a small app.
  • The Argo CD path currently manages only the HTTP route; HTTPS is applied out of band (see k8s/README.md). Unifying them is future work.

Alternatives considered

  • Docker Compose — simpler, but no autoscaling/self-healing and weaker as a learning target for the workshop.
  • A single binary behind a reverse proxy — fine for one instance, but doesn’t demonstrate load balancing across replicas.