🔥 Advanced Kubernetes Troubleshooting Questions & Solutions
Let’s dive deeper into real-world Kubernetes troubleshooting scenarios with detailed step-by-step solutions. These questions will help you debug cluster issues like a pro! 🚀
1️⃣ How do you troubleshoot a pod stuck in Terminating state?
✅ Possible Causes & Fixes:
🔹 Check if the pod is stuck due to finalizers:
kubectl get pod <pod-name> -n <namespace> -o json | jq .metadata.finalizers
🔹 Force delete the pod:
kubectl delete pod <pod-name> --grace-period=0 --force -n <namespace>
🔹 Check if the node is unresponsive:
kubectl get nodes
🔹 If the node is down, drain and remove it:
kubectl drain <node-name> --ignore-daemonsets --delete-emptydir-data
kubectl delete node <node-name>
2️⃣ How do you debug ErrImagePull and ImagePullBackOff issues?
✅ Possible Causes & Fixes:
🔹 Check pod events for details:
kubectl describe pod <pod-name>
🔹 Ensure the image exists and is accessible:
docker pull <image-name>
🔹 Check for missing authentication (private registry):
imagePullSecrets:
- name: my-docker-secret
🔹 If using a private registry, verify the secret exists:
kubectl get secrets -n <namespace>
🔹 Manually delete and recreate the pod:
kubectl delete pod <pod-name>
3️⃣ How do you check why a pod is evicted?
✅ Possible Causes & Fixes:
🔹 List evicted pods:
kubectl get pods --field-selector=status.phase=Failed
🔹 Check eviction reason:
kubectl describe pod <evicted-pod-name>
🔹 If caused by memory pressure, increase memory limits:
resources:
requests:
memory: "512Mi"
limits:
memory: "1Gi"
🔹 Manually remove evicted pods:
kubectl delete pod <pod-name>
4️⃣ How do you troubleshoot slow pod scheduling?
✅ Possible Causes & Fixes:
🔹 Check pending pods:
kubectl get pods --field-selector=status.phase=Pending
🔹 Check if the cluster is out of resources:
kubectl describe node <node-name>
🔹 Check pod scheduling events:
kubectl get events --sort-by=.metadata.creationTimestamp
🔹 Ensure node taints/tolerations allow scheduling:
kubectl describe node <node-name> | grep -i taint
🔹 Verify affinity/anti-affinity settings:
affinity:
nodeAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
nodeSelectorTerms:
- matchExpressions:
- key: "disktype"
operator: In
values:
- ssd
5️⃣ How do you fix CrashLoopBackOff due to liveness probe failures?
✅ Possible Causes & Fixes:
🔹 Check logs for errors:
kubectl logs <pod-name>
🔹 Check liveness probe configuration:
livenessProbe:
httpGet:
path: /healthz
port: 8080
initialDelaySeconds: 10
periodSeconds: 5
🔹 Test if the probe endpoint is accessible from within the pod:
kubectl exec -it <pod-name> -- curl localhost:8080/healthz
🔹 If needed, disable liveness probe temporarily:
livenessProbe: null
6️⃣ How do you fix Node Not Ready issues?
✅ Possible Causes & Fixes:
🔹 Check node status:
kubectl get nodes
🔹 Inspect Kubelet logs:
journalctl -u kubelet -f
🔹 Restart the Kubelet service:
systemctl restart kubelet
🔹 Check disk space:
df -h
🔹 Verify node taints are not preventing scheduling:
kubectl describe node <node-name> | grep -i taint
7️⃣ How do you fix a failing Ingress?
✅ Possible Causes & Fixes:
🔹 Check Ingress resources:
kubectl get ingress -n <namespace>
🔹 Describe the Ingress to check for errors:
kubectl describe ingress <ingress-name> -n <namespace>
🔹 Ensure the correct backend service exists:
kubectl get svc -n <namespace>
🔹 Check if Ingress Controller is running:
kubectl get pods -n kube-system | grep ingress
🔹 Verify DNS resolution:
nslookup my-app.example.com
8️⃣ How do you troubleshoot Kubernetes persistent volume (PV) issues?
✅ Possible Causes & Fixes:
🔹 Check PV status:
kubectl get pv
🔹 Check Persistent Volume Claim (PVC) status:
kubectl get pvc -n <namespace>
🔹 Describe the PVC for errors:
kubectl describe pvc <pvc-name> -n <namespace>
🔹 Ensure the storage class is available:
kubectl get storageclass
🔹 If using AWS EBS, verify the disk is attached:
aws ec2 describe-volumes --filters Name=tag:KubernetesCluster,Values=my-cluster
9️⃣ How do you fix high CPU/memory usage in Kubernetes?
✅ Possible Causes & Fixes:
🔹 Check pod resource usage:
kubectl top pod -n <namespace>
🔹 Check node resource usage:
kubectl top node
🔹 Increase CPU/memory limits:
resources:
requests:
cpu: "250m"
memory: "512Mi"
limits:
cpu: "500m"
memory: "1Gi"
🔹 If using Horizontal Pod Autoscaler (HPA), scale based on CPU:
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
name: my-app-hpa
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: my-app
minReplicas: 2
maxReplicas: 10
metrics:
- type: Resource
resource:
name: cpu
target:
type: Utilization
averageUtilization: 80
🔟 How do you restart all pods in a namespace?
✅ Solution:
kubectl delete pods --all -n <namespace>
or
kubectl rollout restart deployment <deployment-name> -n <namespace>
🔥 Summary
✔ Use kubectl describe & kubectl logs for debugging.
✔ Check node, pod, service, and network issues.
✔ Restart pods, nodes, or Ingress controllers if necessary.
✔ Monitor performance using kubectl top and HPA.
🚀 Want More Kubernetes Troubleshooting Tips? Let us know! 🔥
Kubernetes, Troubleshooting, DevOps, CloudComputing, kube-proxy, Containers, Microservices, K8s, Networking, ClusterManagement, Debugging
