50 Kubernetes (K8s) Errors and Solutions

Kubernetes also known as K8s is an open source platform for containerized applications which can automate the deployment, scaling up & down, and manage. Originally K8s is developed by Google and now it is being maintained by the Cloud Native Computing Foundation (CNCF).

Why we say Kubernetes as K8s ?

A simple and minimalistic illustration of Kubernetes errors

Kubernetes shorthand notation is K8s. The primarily reason to use shorthand notation is to simplify its spelling and pronunciation. The term “Kubernetes” itself comes from the Greek word κυβερνήτης (kybernetes) which means “helmsman” or “pilot,” reflecting its application in steering and managing containerized applications. The explanation is below why it is called K8s.

  • The word count in Kubernetes has 10 characters in total.
  • By taking the first letter (K) and the last letter (s) and replacing the 8 letters in between with the digit 8, it becomes K8s.

50 Kubernetes Errors and Solutions

Here is the list of 50 Kubernetes errors and solutions, covering common scenarios and their fixes.

  1. Cluster Creation Issues
    • Error: Failed to initialize Kubernetes cluster (e.g., kubeadm init fails).
      Solution: Check network settings and disable swap (swapoff -a).
    • Error: Node not joining the cluster.
      Solution: Verify token validity and connectivity to the control plane.
    • Error: Unsupported Kubernetes version.
      Solution: Upgrade kubectl, kubeadm, and kubelet to compatible versions.
  2. Pod Issues

    • Error: Pod stuck in Pending state.
      Solution: Ensure sufficient cluster resources and check kubectl describe pod.
    • Error: Pod in CrashLoopBackOff.
      Solution: Analyze logs with kubectl logs and debug application errors.
    • Error: Container not starting.
      Solution: Verify image name, tag, and pull policy.
    • Error: Pod cannot connect to another pod.
      Solution: Verify network policies and DNS resolution.
  3. Service and Networking

    • Error: Service not exposing pod.
      Solution: Check labels in the pod selector match the pod labels.
    • Error: External IP not assigned to LoadBalancer service.
      Solution: Ensure cloud provider integration is configured correctly.
    • Error: DNS resolution failure.
      Solution: Check kube-dns or CoreDNS logs.
    • Error: NodePort service inaccessible.
      Solution: Verify firewall and network configuration.
  4. Persistent Volumes and Storage

    • Error: PVC stuck in Pending.
      Solution: Ensure StorageClass is available and matches PVC requirements.
    • Error: PV not bound to PVC.
      Solution: Verify access modes and storage capacity match.
    • Error: Read-only file system error in container.
      Solution: Check volume mount configurations.
  5. Deployment Issues

    • Error: Deployment update fails.
      Solution: Check for immutable field changes.
    • Error: Rolling update stuck.
      Solution: Inspect pod readiness and health checks.
    • Error: Unexpected scaling behavior.
      Solution: Adjust HPA (Horizontal Pod Autoscaler) settings and CPU/memory limits.
  6. RBAC (Role-Based Access Control)

    • Error: Forbidden error when accessing resources.
      Solution: Assign proper roles and bindings to the user/service account.
    • Error: ServiceAccount not found.
      Solution: Ensure the ServiceAccount exists in the correct namespace.
  7. Cluster Node Issues

    • Error: Node marked as NotReady.
      Solution: Check kubelet logs and verify node resources.
    • Error: Node eviction due to high memory usage.
      Solution: Adjust eviction thresholds and monitor resource usage.
    • Error: DaemonSet pod not running on a node.
      Solution: Verify taints and tolerations.
  8. Ingress Issues

    • Error: 404 response from Ingress.
      Solution: Check Ingress rules and ensure the backend service is reachable.
    • Error: Ingress TLS configuration not working.
      Solution: Verify secret for TLS and ensure certificates are valid.
  9. Image Pull Issues

    • Error: Image pull back-off.
      Solution: Verify image repository credentials.
    • Error: Invalid image reference.
      Solution: Ensure the image name and tag are correct.
  10. Autoscaling Issues

    • Error: HPA not scaling pods. e.g. HPA status shows “Desired Replicas: 1” despite high load.
      Solution: Verify metrics-server is running and reachable. use command kubectl get deployment metrics-server -n kube-system
    • Error: ClusterAutoscaler not provisioning nodes.
      Solution: Check resource requests and limits for scalability.
  11. Security

    • Error: Pod cannot mount secrets/configmaps.
      Solution: Ensure RBAC permissions for the pod’s ServiceAccount.
    • Error: Unauthorized error accessing API server.
      Solution: Verify API token and RBAC permissions.
  12. Helm

    • Error: Helm release upgrade failed.
      Solution: Use helm rollback and analyze release history.
    • Error: Chart values not applied.
      Solution: Ensure correct values.yaml format.
  13. Monitoring

    • Error: Prometheus not scraping metrics.
      Solution: Check scrape config and target pod annotations.
    • Error: Grafana dashboards missing data.
      Solution: Verify data source connectivity.
  14. Logging

    • Error: Fluentd/Log collector not capturing logs.
      Solution: Ensure log file paths are correct and accessible.
    • Error: Logs missing in EFK stack.
      Solution: Check Elasticsearch and Fluentd integration.
  15. Upgrades

    • Error: kubeadm upgrade fails.
      Solution: Follow the official upgrade path and resolve pre-check issues.
    • Error: Downtime during cluster upgrade.
      Solution: Use surge upgrades or partitioned node upgrades.
  16. Performance

    • Error: High API server latency.
      Solution: Enable caching and optimize API requests.
    • Error: Resource starvation on nodes.
      Solution: Optimize pod resource requests and cluster autoscaling.
  17. Advanced Scenarios

    • Error: ClusterIP service unreachable.
      Solution: Verify iptables or ebpf rules.
    • Error: CoreDNS pod crash.
      Solution: Check CoreDNS configmap for errors.
    • Error: Pod security policy blocking deployment.
      Solution: Update PSP to allow the required permissions.
  18. Miscellaneous

    • Error: kube-proxy not working.
      Solution: Restart kube-proxy daemon and check its logs.
    • Error: Metrics-server not running.
      Solution: Verify APIService and certificate configuration.
    • Error: ETCD out of disk space.
      Solution: Clean up unused data or scale storage capacity.
    • Error: Scheduler not placing pods.
      Solution: Check pod tolerations and node taints.
    • Error: Incorrect time sync across nodes.
      Solution: Ensure ntp or chrony is running.
    • Error: kube-apiserver down.
      Solution: Check control plane node health and logs.
    • Error: Network plugin failure.
      Solution: Restart the plugin and check configurations.

By addressing these 50 errors and solutions, you can build a robust Kubernetes environment that supports reliable and scalable application deployments

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