version: 1
id: kubernetes-troubleshooting
title: Troubleshoot a Broken Release
summary: Fix ImagePullBackOff and an empty Service selector so the api workload becomes Ready and has Endpoints.
difficulty: advanced
estimatedMinutes: 40
prerequisites: [kubernetes-rbac]
image: alpine/k8s:1.31.4
shell: /bin/bash
runtime:
  type: k3d
setup:
  - "kubectl apply -f - <<'EOF'\napiVersion: apps/v1\nkind: Deployment\nmetadata:\n  name: api\nspec:\n  replicas: 2\n  selector:\n    matchLabels:\n      app: api\n  template:\n    metadata:\n      labels:\n        app: api\n    spec:\n      containers:\n        - name: api\n          image: nginx:bogus-tag\n          ports:\n            - containerPort: 80\n---\napiVersion: v1\nkind: Service\nmetadata:\n  name: api\nspec:\n  selector:\n    app: web\n  ports:\n    - port: 80\n      targetPort: 80\nEOF"
tasks:
  - id: restore-api
    title: Restore pods and Service endpoints
    description: 'Fix Deployment api to use image nginx:1.27-alpine (keep 2 replicas), fix Service api selector to app=api, save manifests to /workspace/deployment.yaml and /workspace/service.yaml, apply both, and wait until pods are Ready with Endpoints present.'
    hints:
      - kubectl get pods and kubectl describe pod show ImagePullBackOff.
      - kubectl get endpoints api will be empty until the Service selector matches pod labels.
      - Export fixed YAML with kubectl get ... -o yaml > file after editing, or edit then apply -f.
    checks:
      - type: file
        name: Deployment manifest saved
        path: /workspace/deployment.yaml
        value: "nginx:1.27-alpine"
      - type: file
        name: Service selects api
        path: /workspace/service.yaml
        value: "app: api"
      - type: kubernetes
        name: Image fixed
        command: "kubectl get deploy api -o jsonpath='{.spec.template.spec.containers[0].image}' | grep -q 'nginx:1.27-alpine'"
      - type: kubernetes
        name: Service selector fixed
        command: "kubectl get svc api -o jsonpath='{.spec.selector.app}' | grep -q api"
      - type: kubernetes
        name: Pods ready
        command: kubectl wait --for=condition=ready pod -l app=api --timeout=120s
      - type: kubernetes
        name: Endpoints populated
        command: "test \"$(kubectl get endpoints api -o jsonpath='{.subsets[*].addresses[*].ip}' | wc -w)\" -ge 1"
limits: {cpus: "1.0", memory: 512m, pids: 256, timeout: 3600, network: true}