Minimal K3s, Cilium, and Hubble playground

This repository runs a single-node K3s cluster inside Docker Compose with Cilium and Hubble. It is a small learning environment for observing service traffic and trying the Hubble Observer API.

Start and verify

cd src
docker compose up -d --build
docker compose exec tools bash /workspace/scripts/verify.sh

The generated kubeconfig is written to src/.kube and is not committed. Cluster state is kept in Docker volumes. Do not use docker compose down -v unless the cluster should be reset.

Minimal demo

docker compose exec tools bash /workspace/workloads/topology-demo/apply.sh
docker compose exec tools hubble observe -P --namespace demo
docker compose exec tools hubble observe -P --namespace demo --verdict DROPPED

The frontend calls one API route every five seconds. The API proxies that route to the backend's one response endpoint.

Hubble access

The Relay and UI are internal services. Use local forwarding when needed:

docker compose exec tools cilium hubble port-forward
kubectl -n kube-system port-forward service/hubble-ui 8080:80

The small Go experiment is under src/experiments/hubble-client and covers ServerStatus, GetNodes, GetNamespaces, and bounded GetFlows calls.