Here is a list of 100 kubectl
commands that can be useful for diagnosing issues in a Kubernetes cluster.
Cluster Information:
1. Show the Kubernetes version: kubectl version
2. Display cluster information: kubectl cluster-info
3. List all nodes in the cluster: kubectl get nodes
4. Describe a specific node: kubectl describe node <node-name>
5. List all namespaces: kubectl get namespaces
6. List all pods in all namespaces: kubectl get pods --all-namespaces
Pod Diagnostics:
1. List pods in a specific namespace: kubectl get pods -n <namespace>
2. Describe a pod: kubectl describe pod <pod-name> -n <namespace>
3. View pod logs: kubectl logs <pod-name> -n <namespace>
4. Tail pod logs: kubectl logs -f <pod-name> -n <namespace>
5. Execute a command in a pod: kubectl exec -it <pod-name> -n <namespace> -- <command>
Pod Health Checks:
1. Check pod readiness: kubectl get pods <pod-name> -n <namespace> -o jsonpath='{.status.conditions[?(@.type=="Ready")].status}'
2. Check pod events: kubectl get events -n <namespace> --field-selector
involvedObject.name
=<pod-name>
Service Diagnostics:
1. List all services in a namespace: kubectl get svc -n <namespace>
2. Describe a service: kubectl describe svc <service-name> -n <namespace>
Deployment Diagnostics:
1. List all deployments in a namespace: kubectl get deployments -n <namespace>
2. Describe a deployment: kubectl describe deployment <deployment-name> -n <namespace>
3. View rollout status: kubectl rollout status deployment/<deployment-name> -n <namespace>
4. View rollout history: kubectl rollout history deployment/<deployment-name> -n <namespace>
StatefulSet Diagnostics:
1. List all StatefulSets in a namespace: kubectl get statefulsets -n <namespace>
2. Describe a StatefulSet: kubectl describe statefulset <statefulset-name> -n <namespace>
ConfigMap and Secret Diagnostics:
1. List ConfigMaps in a namespace: kubectl get configmaps -n <namespace>
2. Describe a ConfigMap: kubectl describe configmap <configmap-name> -n <namespace>
3. List Secrets in a namespace: kubectl get secrets -n <namespace>
4. Describe a Secret: kubectl describe secret <secret-name> -n <namespace>
Namespace Diagnostics:
1. Describe a namespace: kubectl describe namespace <namespace-name>
Resource Usage:
1. Check resource usage for a pod: kubectl top pod <pod-name> -n <namespace>
2. Check resource usage for nodes: kubectl top nodes
Networking Diagnostics:
1. Show the IP addresses of pods in a namespace: kubectl get pods -n <namespace -o custom-columns=POD:
metadata.name
,IP:status.podIP --no-headers
2. List all network policies in a namespace: kubectl get networkpolicies -n <namespace>
3. Describe a network policy: kubectl describe networkpolicy <network-policy-name> -n <namespace>
Persistent Volume (PV) and Persistent Volume Claim (PVC) Diagnostics:
1. List PVs: kubectl get pv
2. Describe a PV: kubectl describe pv <pv-name>
3. List PVCs in a namespace: kubectl get pvc -n <namespace>
4. Describe a PVC: kubectl describe pvc <pvc-name> -n <namespace>
Node Diagnostics:
1.
Get the list of pods running on a specific node: kubectl get pods --field-selector spec.nodeName=<node-name> -n <namespace>
Resource Quotas and Limits:
1. List resource quotas in a namespace: kubectl get resourcequotas -n <namespace>
2. Describe a resource quota: kubectl describe resourcequota <resource-quota-name> -n <namespace>
Custom Resource Definitions (CRD) Diagnostics:
1. List custom resources in a namespace: kubectl get <custom-resource-name> -n <namespace>
2. Describe a custom resource: kubectl describe <custom-resource-name> <custom-resource-instance-name> -n <namespace>
Remember to replace <namespace>
, <pod-name>
, <service-name>
, <deployment-name>
, <statefulset-name>
, <configmap-name>
, <secret-name>
, <namespace-name>
, <pv-name>
, <pvc-name>
, <node-name>
, <network-policy-name>
, <resource-quota-name>
, <custom-resource-name>
, and <custom-resource-instance-name>
with your specific values when using these commands. These commands should help you diagnose various aspects of your Kubernetes cluster and applications running within it.
Resource Scaling and Autoscaling:
1. Scale a deployment: kubectl scale deployment <deployment-name> --replicas=<replica-count> -n <namespace>
2. Set autoscaling for a deployment: kubectl autoscale deployment <deployment-name> --min=<min-pods> --max=<max-pods> --cpu-percent=<cpu-percent> -n <namespace>
3. Check horizontal pod autoscaler status: kubectl get hpa -n <namespace>
Job and CronJob Diagnostics:
1. List all jobs in a namespace: kubectl get jobs -n <namespace>
2. Describe a job: kubectl describe job <job-name> -n <namespace>
3. List all cron jobs in a namespace: kubectl get cronjobs -n <namespace>
4. Describe a cron job: kubectl describe cronjob <cronjob-name> -n <namespace>
Volume Diagnostics:
1. List persistent volumes (PVs) sorted by capacity: kubectl get pv --sort-by=.
spec.capacity.storage
2. Check PV reclaim policy: kubectl get pv <pv-name> -o=jsonpath='{.spec.persistentVolumeReclaimPolicy}'
3. List all storage classes: kubectl get storageclasses
Ingress and Service Mesh Diagnostics:
1. List all ingresses in a namespace: kubectl get ingress -n <namespace>
2. Describe an ingress: kubectl describe ingress <ingress-name> -n <namespace>
3. List all VirtualServices (Istio) in a namespace: kubectl get virtualservices -n <namespace>
4. Describe a VirtualService (Istio): kubectl describe virtualservice <virtualservice-name> -n <namespace>
Pod Network Troubleshooting:
1. Run a network diagnostic pod (e.g., busybox) for debugging: kubectl run -it --rm --restart=Never --image=busybox net-debug-pod -- /bin/sh
2. Test connectivity from a pod to a specific endpoint: kubectl exec -it <pod-name> -n <namespace> -- curl <endpoint-url>
3. Trace network path from one pod to another: kubectl exec -it <source-pod-name> -n <namespace> -- traceroute <destination-pod-ip>
4. Check DNS resolution from a pod: kubectl exec -it <pod-name> -n <namespace> -- nslookup <domain-name>
Config and Resource Validation:
1. Validate a Kubernetes YAML file without applying it: kubectl apply --dry-run=client -f <yaml-file>
2.
Validate a pod’s security context and capabilities: kubectl auth can-i list pods --as=system:serviceaccount:<namespace>:<serviceaccount-name>
RBAC and Security:
1. List roles and role bindings in a namespace: kubectl get roles,rolebindings -n <namespace>
2. Describe a role or role binding: kubectl describe role <role-name> -n <namespace>
Service Account Diagnostics:
1. List service accounts in a namespace: kubectl get serviceaccounts -n <namespace>
2. Describe a service account: kubectl describe serviceaccount <serviceaccount-name> -n <namespace>
Node Drain and Uncordon:
1. Drain a node for maintenance: kubectl drain <node-name> --ignore-daemonsets
2. Uncordon a previously drained node: kubectl uncordon <node-name>
Resource Cleanup:
1. Delete a pod forcefully (not recommended): kubectl delete pod <pod-name> -n <namespace> --grace-period=0 --force
Pod Affinity and Anti-Affinity:
1. List pod affinity rules for a pod: kubectl get pod <pod-name> -n <namespace> -o=jsonpath='{.spec.affinity}'
2.
List pod anti-affinity rules for a pod: kubectl get pod <pod-name> -n <namespace> -o=jsonpath='{.spec.affinity.podAntiAffinity}'
Pod Security Policies (PSP):
1. List all pod security policies (if enabled): kubectl get psp
Kubernetes Events:
1. View recent cluster events: kubectl get events --sort-by=.metadata.creationTimestamp
2. Filter events by a specific namespace: kubectl get events -n <namespace>
Node Troubleshooting:
1. Check node conditions: kubectl describe node <node-name> | grep Conditions -A5
2. List node capacity and allocatable resources: kubectl describe node <node-name> | grep -E "Capacity|Allocatable"
Ephemeral Containers (Kubernetes 1.18+):
1. Run an ephemeral debugging container: kubectl debug -it <pod-name> -n <namespace> --image=<debug-image> -- /bin/sh
Resource Metrics (Metrics Server required):
1.
Get CPU and Memory usage for pods: kubectl top pod -n <namespace>
Kubelet Diagnostics:
1. View kubelet logs on a node: kubectl logs -n kube-system kubelet-<node-name>
Advanced Debugging with Telepresence:
1. Debug a pod with Telepresence: telepresence --namespace <namespace> --swap-deployment <pod-name>
Kubeconfig and Contexts:
1. List available contexts: kubectl config get-contexts
2. Switch to a different context: kubectl config use-context <context-name>
Pod Security Standards (PodSecurity admission controller):
1. List PodSecurityPolicy (PSP) violations: kubectl get psp -A | grep -vE 'NAME|REVIEWED'
Pod Disruption Budget (PDB) Diagnostics:
1. List all PDBs in a namespace: kubectl get pdb -n <namespace>
2. Describe a PDB: kubectl describe pdb <pdb-name> -n <namespace>
Resource Lock Diagnostics (if using resource locks):
1. List resource locks in a namespace: kubectl get resourcelocks -n <namespace>
Service Endpoints and DNS:
1. List service endpoints for a service: kubectl get endpoints <service-name> -n <namespace>
2. Check DNS configuration in a pod: kubectl exec -it <pod-name> -n <namespace> -- cat /etc/resolv.conf
Custom Metrics (Prometheus, Grafana):
1. Query Prometheus metrics: Use kubectl port-forward
to access Prometheus and Grafana services to query custom metrics.
Pod Priority and Preemption:
1. List priority classes: kubectl get priorityclasses
Pod Overhead (Kubernetes 1.18+):
1. List overhead in a pod: kubectl get pod <pod-name> -n <namespace> -o=jsonpath='{.spec.overhead}'
Volume Snapshot Diagnostics (if using volume snapshots):
1. List volume snapshots: kubectl get volumesnapshot -n <namespace>
2. Describe a volume snapshot: kubectl describe volumesnapshot <snapshot-name> -n <namespace>
Resource Deserialization Diagnostics:
1. Deserialize and print a Kubernetes resource: kubectl get <resource-type> <resource-name> -n <namespace> -o=json
Node Taints:
1. List node taints: kubectl describe node <node-name> | grep Taints
Mutating and Validating Webhook Configurations:
1. List mutating webhook configurations: kubectl get mutatingwebhookconfigurations
2. List validating webhook configurations: kubectl get validatingwebhookconfigurations
Pod Network Policies:
1.
List pod network policies in a namespace: kubectl get networkpolicies -n <namespace>
Node Conditions (Kubernetes 1.17+):
List node conditions: kubectl get nodes -o custom-columns=NODE:.metadata.name,READY:.status.conditions[?(@.type==”Ready”)].status -l ‘node-role.kubernetes.io/worker=’Audit Logs:
1. Retrieve audit logs (if enabled): Check your Kubernetes audit log configuration for the location of audit logs.
Node Operating System Details:
1. Get the node’s OS information: kubectl get node <node-name> -o jsonpath='{.status.nodeInfo.osImage}'
List All Running Pods in All Namespaces (Short Command):
1. List all running pods in all namespaces in a short format: kubectl get pods --all-namespaces
These commands should cover a wide range of diagnostics scenarios in Kubernetes. Make sure to replace placeholders like <namespace>
, <pod-name>
, <deployment-name>
, etc., with actual values specific to your cluster and use case.