Challenge on ,
Reach a Distroless Container's Debug Endpoint From a Sidecar Container
A distroless container serves a debug interface on its own loopback address. Can you reach this debug endpoint using nothing but standard Docker commands?
Challenges
Focused, hands-on DevOps and server-side problems with hints, feedback, and automated solution checks.
Challenge on ,
Debug a Go Container Image That Fails to Start After a Recent Change
A Go service that has always been shipped as a static binary in a scratch-y image suddenly fails to start in a container, while the local build works as before. Find what recent changes caused it and fix the image without reverting them.
Challenge on ,
Debug a Failing Kubernetes Job
by Omkar Shelke
A Job manifest at /home/laborant/batch-job.yaml is exiting with a non-zero exit status. The Job has limited retries configured. Inspect the cluster and the manifest to find the bug, fix it, and reapply.
Challenge on
Inject a Config File Without Overwriting the Image's Existing Directory
by Omkar Shelke
A webapp deployment in the prod namespace is stuck in CrashLoopBackOff. The application's startup probe checks that its existing config directory is intact before the container is marked healthy. Fix the deployment so configuration is injected correctly and the pod reaches Running state with its health check endpoint responding on port 8080.
Challenge on
Resolve ContainerCreating Issue Caused by Missing ConfigMap
by Omkar Shelke
A Deployment is stuck with Pods in ContainerCreating state because the required ConfigMap was not created. Fix the issue to make the application accessible.
Challenge on
Diagnose Why a DaemonSet Skips the Control Plane Node
by Omkar Shelke
Troubleshoot and update a Kubernetes DaemonSet so that its Pods run on all nodes in the cluster, including the control plane.
Challenge on
Troubleshoot a Website That Is Not Accessible
by Omkar Shelke
A web application is deployed but the website is not accessible. Investigate and fix the issue.
Challenge on ,
Execute Host Commands Inside a Running Container
Leverage your knowledge of Linux namespaces to reach an application's internal debug interface without installing anything into the container.
Challenge on ,
Run a Sidecar Container in the Namespace of Another Container
Learn how to run multiple Docker containers sharing the same PID, IPC, and network namespaces - a foundation of many advanced container use cases, including Kubernetes Pods construction and container debugging tools.
Challenge on
Docker 101: Execute Commands in a Running Container
Learn how to execute commands inside running containers using 'docker exec' - a crucial skill for debugging containerized applications and exploring container environments.