Top 10 Common Kubernetes Issues and How to Fix Them

Problem 1: Kubernetes service access failure (certificate issue)

Cause analysis: The certificate is unrecognised, often due to a custom or expired certificate.

Solution: Update the certificate.

Problem 2: Kubernetes service access failure (port‑mapping error)

Example error:

curl: (7) Failed connect to 10.103.22.158:3000; Connection refused

Cause analysis: Port mapping is incorrect; the service runs but cannot be reached.

Solution: Delete the Service and recreate it with the correct port mapping.

kubectl delete svc nginx-deployment

Problem 3: Service exposure failure (service already exists)

Example error:

Error from server (AlreadyExists): services "nginx-deployment" already exists

Cause analysis: The service has already been created.

Solution: Delete the existing Service and recreate it with the proper port mapping.

Problem 4‑1: External access to a ClusterIP service is blocked

Cause analysis: The Service type is ClusterIP, which does not expose the service outside the cluster.

Solution: Change the Service type to NodePort so it can be accessed via any cluster node.

kubectl edit svc nginx-deployment

Problem 4‑2: Pod stuck in ErrImagePull

Cause analysis: The container image cannot be pulled.

Solution: Replace the image with a valid one.

Problem 5: Init container remains in an abnormal state

Observed pod status:

NAME   READY   STATUS        RESTARTS   AGE
myapp-pod   0/1   Init:0/2   0   20s

Cause analysis: The init container never finishes, preventing the main container from starting.

Additional error:

Error from server (BadRequest): container "myapp-container" in pod "myapp-pod" is waiting to start: PodInitializing

Solution: Ensure the init container completes successfully, often by fixing the image.

Problem 6: DNS resolution failure during init container execution

CoreDNS cannot resolve the service name, producing NXDOMAIN errors.

Solution: Create the required Service and add its name to CoreDNS so that DNS queries succeed.

kubectl apply -f myservice.yaml

Problem 7: Pod repeatedly crashes (CrashLoopBackOff)

Cause analysis: The container image is faulty, causing the container to restart continuously.

Solution: Replace the problematic image with a working one.

Problem 8: Pod creation fails with various states (Pending, Error, CrashLoopBackOff)

Observed status progression:

readiness-httpget-pod 0/1 Pending 0 0s
...
readiness-httpget-pod 0/1 CrashLoopBackOff 4 82s

Cause analysis: Image problems prevent the container from starting.

Solution: Use a correct, pullable image.

Problem 9: Pod never reaches Ready state

Observed status: readiness-httpget-pod 0/1 Running 0 116s Cause analysis: The pod’s command fails, so required resources are not obtained.

Solution: Exec into the container and create the resources defined in the pod’s YAML.

Problem 10: Pod creation fails due to malformed YAML (Chinese characters)

Cause analysis: The YAML file contains invalid Chinese characters.

Solution: Edit the myregistrykey content to remove the illegal characters.

These troubleshooting steps, combined with the shown kubectl commands and error outputs, provide a practical reference for diagnosing and resolving common Kubernetes deployment issues.