Troubleshooting Kubernetes Deployments

Introduction:

Kubernetes simplifies application deployment and scaling—but when things go wrong, debugging can feel like finding a needle in a haystack. From pods stuck in CrashLoopBackOff to misconfigured services, Kubernetes deployments can encounter various issues.

Common Deployment Issues in Kubernetes:

Before diving into troubleshooting, let’s identify the most common issues developers face:

• Pods not starting or crashing (CrashLoopBackOff, ImagePullBackOff)

• Containers running but application unreachable

• Incorrect configuration (ConfigMaps, Secrets)

• Unhealthy liveness/readiness probes

• Insufficient resources or node issues

• RBAC permission errors

• Network connectivity problems (DNS, Services)

Step-by-Step Troubleshooting Checklist:

1.Check Deployment Status

Start by examining the deployment:

• kubectl get deployments

• kubectl describe deployment <deployment-name>

Look for errors in Events like failed scheduling, missing images, or replica set issues.

2. Inspect Pods

Get a list of pods and check their status:

• kubectl get pods

• kubectl describe pod <pod-name>

Key indicators:

• Pending: Likely a scheduling or resource issue

• CrashLoopBackOff: Container is crashing repeatedly

• ImagePullBackOff: Image not found or authentication failed.

  
  

3.View Pod Logs

Check logs of the affected pod:

• kubectl logs <pod-name>

• kubectl logs <pod-name> -c <container-name> # if multi-container pod

Look for application-level errors, stack traces, or startup failures.

4.Verify ConfigMaps and Secrets

Incorrect or missing configuration can break apps:

• kubectl get configmap

• kubectl get secret

Check mounts and values used in the pod spec.

5.Inspect RBAC & Service Accounts

If your pods need permissions (e.g., access to the Kubernetes API or secrets), verify:

• kubectl auth can-i <verb> <resource> --as <serviceaccount>

Review role bindings and service account usage in the deployment YAML.

6.Debug Services and Networking

If pods are running but unreachable:

• kubectl get svc

• kubectl describe svc <service-name>

  Inspect DNS and service resolution:

• kubectl exec -it <pod-name> -- nslookup <service-name>

  
  

7.Monitor Cluster Health

Check node and resource usage:

• kubectl top nodes kubectl top pods

Also ensure your cluster isn't overcommitted on CPU/memory, which can lead to eviction or unschedulable pods.

 Tools for Easier Debugging:

• Lens – Kubernetes IDE for real-time cluster monitoring

• K9s – Terminal UI for managing Kubernetes clusters

• Stern – Tail logs from multiple pods in real-time

• kubectl debug – Create ephemeral debug containers.

Tips and Best Practices:

• Always define readiness and liveness probes

• Use resource requests/limits to avoid overloading nodes

• Leverage Helm or Kustomize for easier configuration management

• Use namespaces to isolate environments and ease debugging

• Automate logging and monitoring with tools like Prometheus, Grafana, and Loki.

  
  

Conclusion:

Troubleshooting Kubernetes deployments requires a systematic approach, combining kubectl mastery with a deep understanding of how Kubernetes components interact. By following this guide, you can resolve most issues quickly and confidently, turning chaos into clarity.