kubectl-skill

# kubectl Skill Execute Kubernetes cluster management operations using the `kubectl` command-line tool. ## Overview This skill enables agents to: - **Query Resources** — List and get details about pods, deployments, services, nodes, etc. - **Deploy & Update** — Create, apply, patch, and update Kubernetes resources - **Debug & Troubleshoot** — View logs, execute commands in containers, inspect events - **Manage Configuration** — Update kubeconfig, switch contexts, manage namespaces - **Monitor Health** — Check resource usage, rollout status, events, and pod conditions - **Perform Operations** — Scale deployments, drain nodes, manage taints and labels ## Prerequisites 1. **kubectl binary** installed and accessible on PATH (v1.20+) 2. **kubeconfig** file configured with cluster credentials (default: `~/.kube/config`) 3. **Active connection** to a Kubernetes cluster ## Quick Setup ### Install kubectl **macOS:** ```bash brew install kubernetes-cli ``` **Linux:** ```bash apt-get install -y kubectl # Ubuntu/Debian yum install -y kubectl # RHEL/CentOS ``` **Verify:** ```bash kubectl version --client kubectl cluster-info # Test connection ``` ## Essential Commands ### Query Resources ```bash kubectl get pods # List all pods in current namespace kubectl get pods -A # All namespaces kubectl get pods -o wide # More columns kubectl get nodes # List nodes kubectl describe pod POD_NAME # Detailed info with events ``` ### View Logs ```bash kubectl logs POD_NAME # Get logs kubectl logs -f POD_NAME # Follow logs (tail -f) kubectl logs POD_NAME -c CONTAINER # Specific container kubectl logs POD_NAME --previous # Previous container logs ``` ### Execute Commands ```bash kubectl exec -it POD_NAME -- /bin/bash # Interactive shell kubectl exec POD_NAME -- COMMAND # Run single command ``` ### Deploy Applications ```bash kubectl apply -f deployment.yaml # Apply config kubectl create -f deployment.yaml # Create resource kubectl apply -f deployment.yaml --dry-run=client # Test ``` ### Update Applications ```bash kubectl set image deployment/APP IMAGE=IMAGE:TAG # Update image kubectl scale deployment/APP --replicas=3 # Scale pods kubectl rollout status deployment/APP # Check status kubectl rollout undo deployment/APP # Rollback ``` ### Manage Configuration ```bash kubectl config view # Show kubeconfig kubectl config get-contexts # List contexts kubectl config use-context CONTEXT # Switch context ``` ## Common Patterns ### Debugging a Pod ```bash # 1. Identify the issue kubectl describe pod POD_NAME # 2. Check logs kubectl logs POD_NAME kubectl logs POD_NAME --previous # 3. Execute debug commands kubectl exec -it POD_NAME -- /bin/bash # 4. Check events kubectl get events --sort-by='.lastTimestamp' ``` ### Deploying a New Version ```bash # 1. Update image kubectl set image deployment/MY_APP my-app=my-app:v2 # 2. Monitor rollout kubectl rollout status deployment/MY_APP -w # 3. Verify kubectl get pods -l app=my-app # 4. Rollback if needed kubectl rollout undo deployment/MY_APP ``` ### Preparing Node for Maintenance ```bash # 1. Drain node (evicts all pods) kubectl drain NODE_NAME --ignore-daemonsets # 2. Do maintenance # ... # 3. Bring back online kubectl uncordon NODE_NAME ``` ## Output Formats The `--output` (`-o`) flag supports multiple formats: - `table` — Default tabular format - `wide` — Extended table with additional columns - `json` — JSON format (useful with `jq`) - `yaml` — YAML format - `jsonpath` — JSONPath expressions - `custom-columns` — Define custom output columns - `name` — Only resource names **Examples:** ```bash kubectl get pods -o json | jq '.items[0].metadata.name' kubectl get pods -o jsonpath='{.items[*].metadata.name}' kubectl get pods -o custom-columns=NAME:.metadata.name,STATUS:.status.phase ``` ## Global Flags (Available to All Commands) ```bash -n, --namespace=<ns> # Operate in specific namespace -A, --all-namespaces # Operate across all namespaces --context=<context> # Use specific kubeconfig context -o, --output=<format> # Output format (json, yaml, table, etc.) --dry-run=<mode> # Dry-run mode (none, client, server) -l, --selector=<labels> # Filter by labels --field-selector=<selector> # Filter by fields -v, --v=<int> # Verbosity level (0-9) ``` ## Dry-Run Modes - `--dry-run=client` — Fast client-side validation (test commands safely) - `--dry-run=server` — Server-side validation (more accurate) - `--dry-run=none` — Execute for real (default) **Always test with `--dry-run=client` first:** ```bash kubectl apply -f manifest.yaml --dry-run=client ``` ## Advanced Topics For detailed reference material, command-by-command documentation, troubleshooting guides, and advanced workflows, see: - [references/REFERENCE.md](references/REFERENCE.md) — Complete kubectl command reference - [scripts/](scripts/) — Helper scripts for common tasks ## Helpful Tips 1. **Use label selectors for bulk operations:** ```bash kubectl delete pods -l app=myapp kubectl get pods -l env=prod,tier=backend ``` 2. **Watch resources in real-time:** ```bash kubectl get pods -w # Watch for changes ``` 3. **Use `-A` flag for all namespaces:** ```bash kubectl get pods -A # See pods everywhere ``` 4. **Save outputs for later comparison:** ```bash kubectl get deployment my-app -o yaml > deployment-backup.yaml ``` 5. **Check before you delete:** ```bash kubectl delete pod POD_NAME --dry-run=client ``` ## Getting Help ```bash kubectl help # General help kubectl COMMAND --help # Command help kubectl explain pods # Resource documentation kubectl explain pods.spec # Field documentation ``` ## Environment Variables - `KUBECONFIG` — Path to kubeconfig file (can include multiple paths separated by `:`) - `KUBECTL_CONTEXT` — Override default context ## Resources - [Official kubectl Docs](https://kubernetes.io/docs/reference/kubectl/) - [kubectl Cheat Sheet](https://kubernetes.io/docs/reference/kubectl/cheatsheet/) - [Kubernetes API Reference](https://kubernetes.io/docs/reference/generated/kubernetes-api/) - [Agent Skills Specification](https://agentskills.io/) --- **Version:** 1.0.0 **License:** MIT **Compatible with:** kubectl v1.20+, Kubernetes v1.20+