End-to-End Kubernetes with Rancher, RKE2, K3s, Fleet, Longhorn, and NeuVector

Examining and Troubleshooting Workloads

Usually, after creating a Deployment, we examine the created resources to make sure they are running as expected. There are usually two things to check:

• System Events: The events are useful system messages that provide information about the state of the workloads (Pods, Deployments, ReplicaSets, etc.). This is where you can see if the Pods are running, if the containers are starting, if the containers are crashing, etc.

• Application Logs: The application logs are useful to debug and troubleshoot issues. This is where you can see the output of the application running in the container. This can be useful to see if the application is running as expected.

ℹ️ Application logs are configured by the creator of the Dockerfile to output logs to the standard output (stdout) or standard error (stderr). This is typically done using a command like RUN ln -sf /dev/stdout /var/log/app.log or any other alternative method. Additionally, processes running in the foreground (not as a daemon) will output logs to the standard output by default (e.g.: CMD ["myapp"]).

We can start by examining our pods:

• Click on Workloads and then Pods.
• Select the pod you want to examine.
• Click on the Recent Events tab to see the events related to the pod.

• Click on Conditions where you can see the different stages of the pod lifecycle (PodStatus). The following conditions are displayed for a pod that is running:

  • PodScheduled: Pod assigned to a node.
  • PodReadyToStartContainers: Pod sandbox created and networking configured.
  • ContainersReady: All containers in the Pod are ready.
  • Initialized: Init containers completed successfully.
  • Ready: Pod can serve requests and join load balancing pools.

• To see the logs, you should use the 3 dots next to the container in the pod and select View Logs.