# KodeKloud: Beta Courses Kubernetes Troubleshooting for Application Developers ## Kubernetes Troubleshooting for Application Developers ### Introduction - [Course Introduction](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Introduction/Course-Introduction/page.md): This course teaches application developers how to troubleshoot Kubernetes issues through real-world scenarios and hands-on labs. ### Prerequisites - [kubectl refresher Intro](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-refresher-Intro/page.md): A comprehensive guide on kubectl commands for troubleshooting and diagnosing Kubernetes applications, highlighting commonly used options for quick issue resolution. - [kubectl get](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-get/page.md): This article explains how to use the kubectl get command to inspect Kubernetes cluster resources effectively. - [kubectl describe](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-describe/page.md): The kubectl describe command offers detailed insights into Kubernetes resources for effective troubleshooting and cluster management. - [kubectl get events](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-get-events/page.md): This article explores using the kubectl get events command to monitor and troubleshoot Kubernetes clusters and applications. - [kubectl logs](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-logs/page.md): This guide explores the `kubectl logs` command for retrieving logs from Kubernetes pods to aid in troubleshooting applications. - [kubectl logs label](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-logs-label/page.md): Learn to efficiently retrieve logs from multiple pods using labels with the kubectl command for better management and troubleshooting. - [kubectl logs timestamps](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-logs-timestamps/page.md): This article explains how to use timestamps with kubectl logs for better Kubernetes troubleshooting and filtering log output by time. - [kubectl logs follow](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-logs-follow/page.md): This guide explains how to stream logs in real time using the kubectl logs command for monitoring application behavior and debugging issues. - [kubectl exec](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-exec/page.md): This article explains the usage of the kubectl exec command for executing commands inside running containers. - [kubectl port forward](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-port-forward/page.md): Learn to use kubectl port-forward for local access to Kubernetes cluster resources without internet exposure, ideal for testing and debugging. - [kubectl auth can i](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-auth-can-i/page.md): This article explores troubleshooting Kubernetes RBAC permissions using the kubectl auth can-i command for analyzing roles, role bindings, and service accounts. - [kubectl top](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-top/page.md): This article explores using the kubectl top command for real-time CPU and memory monitoring in Kubernetes clusters. - [kubectl explain](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-explain/page.md): This article explains the kubectl explain command for accessing inline documentation of Kubernetes API resources and exploring nested fields. - [kubectl diff](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/kubectl-diff/page.md): This article explores the usage of the kubectl diff command to compare YAML configurations with deployed resources in a Kubernetes cluster. - [Kubernetes EphemeralDebug Containers](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/Kubernetes-EphemeralDebug-Containers/page.md): This guide explores using kubectl debug for troubleshooting Kubernetes applications by attaching new containers to running pods without disrupting production workloads. - [k9s Walkthrough](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Prerequisites/k9s-Walkthrough/page.md): This article provides a comprehensive guide to using k9s for managing Kubernetes clusters through a terminal-based interface. ### Troubleshooting Scenarios - [Image Pull Errors](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Image-Pull-Errors/page.md): This guide helps resolve common image pull errors in Kubernetes, including typos, missing credentials, incorrect tags, and DNS issues. - [Crashing Pods](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Crashing-Pods/page.md): This article explores reasons for pods entering a CrashLoopBackOff state and provides troubleshooting steps to resolve these issues effectively. - [Pending Pods](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Pending-Pods/page.md): This article explores common Kubernetes issues causing pods to remain in a pending state and provides actionable solutions for each scenario. - [Case of the Missing Pods](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Case-of-the-Missing-Pods/page.md): This guide explores troubleshooting missing pods in Kubernetes, focusing on deployment issues and resource quotas in the staging namespace. - [Schrodingers Deployment](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Schrodingers-Deployment/page.md): This lesson explores troubleshooting mixed responses in Kubernetes deployments caused by overlapping service selectors. - [Create Container Errors](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Create-Container-Errors/page.md): This guide explores common Kubernetes container creation errors and the container lifecycle stages where these errors occur. - [Config Out of Date](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Config-Out-of-Date/page.md): This lesson explores configuration changes in Kubernetes and how to troubleshoot issues with environment variable updates in running pods. - [Reloader](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Reloader/page.md): This guide introduces Reloader, a Kubernetes controller that automates rolling upgrades of Deployments, DaemonSets, or StatefulSets when ConfigMap or Secret changes occur. - [Endlessly Terminating Pods](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Endlessly-Terminating-Pods/page.md): This article explores reasons and solutions for pods and namespaces in Kubernetes that remain stuck in the terminating state. - [Field Immutability](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Field-Immutability/page.md): This article explains the "field is immutable" error in Kubernetes and how to resolve it when modifying resource configurations. - [enableServiceLinks](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/enableServiceLinks/page.md): This article explains the enableServiceLinks parameter in Kubernetes and its impact on environment variable injection in pods. - [Interns can see our secrets](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Interns-can-see-our-secrets/page.md): This guide addresses diagnosing and resolving a Role-Based Access Control misconfiguration that allows interns to access sensitive information in Kubernetes namespaces. - [Port Mania](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Port-Mania/page.md): This article guides troubleshooting an accessibility issue in a Kubernetes application by diagnosing port configuration mismatches and resolving them for proper connectivity. - [Unreachable Pods Leaky Network Policies](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Unreachable-Pods-Leaky-Network-Policies/page.md): This article discusses troubleshooting network policy issues in Kubernetes namespaces to ensure proper communication between applications while preventing unauthorized connections. - [What the Ingress](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/What-the-Ingress/page.md): This article covers troubleshooting Ingress for Kubernetes applications, focusing on path handling and implementing URL path rewriting to resolve 404 errors. - [Multi Attach Volume Errors](https://notes.kodekloud.com/docs/Kubernetes-Troubleshooting-for-Application-Developers/Troubleshooting-Scenarios/Multi-Attach-Volume-Errors/page.md): This article outlines causes of multi-attach volume errors in Kubernetes and provides workarounds for troubleshooting and resolving these issues.