{
  "id": "node-label-selector",
  "title": "Node Labels and nodeSelector",
  "category": "Cluster Administration",
  "difficulty": "Easy",
  "type": "task",
  "weight": 5,
  "description": "## Node Labels and nodeSelector\n\nLabelling nodes lets you constrain which nodes a pod can be scheduled on, using `nodeSelector` in the pod spec.\n\n**Your task:**\n\n1. Add the label `disk=ssd` to node `k8s-lab`\n2. Create a Pod named `ssd-pod` using `nginx:alpine` that uses `nodeSelector` to target nodes with `disk=ssd`",
  "hints": [
    {
      "title": "Label the node",
      "body": "Use `kubectl label node <node-name> key=value`.",
      "command": "kubectl label node k8s-lab disk=ssd --overwrite"
    },
    {
      "title": "Use nodeSelector in pod spec",
      "body": "Add `nodeSelector: disk: ssd` under `spec` in the pod manifest.",
      "command": "cat <<EOF | kubectl apply -f -\napiVersion: v1\nkind: Pod\nmetadata:\n  name: ssd-pod\nspec:\n  nodeSelector:\n    disk: ssd\n  containers:\n  - name: app\n    image: nginx:alpine\nEOF"
    }
  ],
  "setup_commands": [],
  "validation": {
    "commands": [
      {
        "description": "Node 'k8s-lab' has label disk=ssd",
        "command": "kubectl get node k8s-lab -o jsonpath='{.metadata.labels.disk}'",
        "expected_output": "ssd",
        "match": "exact"
      },
      {
        "description": "Pod 'ssd-pod' has nodeSelector disk=ssd",
        "command": "kubectl get pod ssd-pod -o jsonpath='{.spec.nodeSelector.disk}'",
        "expected_output": "ssd",
        "match": "exact"
      },
      {
        "description": "Pod 'ssd-pod' is Running",
        "command": "kubectl get pod ssd-pod -o jsonpath='{.status.phase}'",
        "expected_output": "Running",
        "match": "exact"
      }
    ]
  },
  "default_namespace": "default",
  "teardown_commands": [
    {
      "command": "kubectl label node k8s-lab disk- 2>/dev/null || true"
    },
    {
      "command": "kubectl delete pod ssd-pod --ignore-not-found --grace-period=0 --force"
    }
  ]
}
