# Run from this lesson's examples directory. Requires Docker, kind, and kubectl.
# All cluster commands explicitly target a disposable local cluster.
kind create cluster --name probes-lesson
docker build -t probes-lesson:v1 .
kind load docker-image probes-lesson:v1 --name probes-lesson
kubectl --context kind-probes-lesson create namespace probes-lesson
kubectl --context kind-probes-lesson apply -f deployment.yaml
kubectl --context kind-probes-lesson -n probes-lesson rollout status deployment/tickets --timeout=180s

# Observe before injecting a failure. Record restart counts for each Pod.
kubectl --context kind-probes-lesson -n probes-lesson get pods -l app=tickets
kubectl --context kind-probes-lesson -n probes-lesson get endpointslices -l kubernetes.io/service-name=tickets -o yaml

# Start an in-cluster client. Its image is already loaded; this adds no new image.
kubectl --context kind-probes-lesson -n probes-lesson run request-check --image=probes-lesson:v1 --image-pull-policy=Never --restart=Never --command -- node -e 'setInterval(() => {}, 1000)'
kubectl --context kind-probes-lesson -n probes-lesson wait --for=condition=Ready pod/request-check --timeout=60s
# Repeat this request before, during, and after the drill. Record status and replica.
kubectl --context kind-probes-lesson -n probes-lesson exec request-check -- node -e "fetch('http://tickets/tickets').then(async r => console.log(r.status, r.headers.get('x-replica'), await r.text()))"

# A marker simulates an unavailable dependency for ONE replica.
kubectl --context kind-probes-lesson -n probes-lesson exec deployment/tickets -- node -e "require('node:fs').writeFileSync('/tmp/database-down', '')"
# Wait at least 15 seconds, then inspect readiness, restarts, and endpoint conditions.
# No restart is expected. Save the affected Pod name from this output.
kubectl --context kind-probes-lesson -n probes-lesson get pods -l app=tickets
kubectl --context kind-probes-lesson -n probes-lesson get endpointslices -l kubernetes.io/service-name=tickets -o yaml

# Replace AFFECTED_POD with that name; do not let exec choose a different replica.
kubectl --context kind-probes-lesson -n probes-lesson exec AFFECTED_POD -- node -e "require('node:fs').unlinkSync('/tmp/database-down')"
# After recovery, simulate a local progress failure in that same replica.
kubectl --context kind-probes-lesson -n probes-lesson exec AFFECTED_POD -- node -e "require('node:fs').writeFileSync('/tmp/stuck', '')"
kubectl --context kind-probes-lesson -n probes-lesson describe pod AFFECTED_POD
# Expect a liveness failure, one container restart, startup gating, then Ready.
# Marker files live in the container writable layer and disappear on restart.

# Cleanup only this disposable cluster when observations are complete.
kind delete cluster --name probes-lesson