Focused, hands-on DevOps and server-side problems with hints, feedback, and automated solution checks.
Sometimes you need an app to talk to a different backend, but its configuration is unknown or the destination address is hard-coded. Practice overriding hostname resolution for a single Docker container to redirect its requests without modifying the app or rebuilding its image.
Explore the container networks of a freshly installed Docker host: find the default network, its subnet and gateway, and the Linux interface behind it.
A common setup for small deployments: two servers (VM or bare-metal), each with a public and a private IP. The app listens on the public port but wants to talk to Redis over the private network. Can you set it up?
Practice accessing a containerized service directly from the Docker host using its IP address.
Learn how to keep a database available to an app running on your workstation without exposing its port to other machines on the network.
A web app is listening inside a container, but the browser can't reach its IP address. Recreate the container so the app is available on port 80 of the Docker host.
Practice discovering what has been published to a remote container repository by listing its tags using crane, regctl, or a direct call to the registry HTTP API.
Create a Pod that uses a postStart lifecycle hook to write a custom message to the nginx welcome page, expose it via a NodePort Service, and verify the hook ran successfully.
Practice using docker login to authenticate against multiple private container registries with different credentials, then pull and push images across them.
Use Kubernetes image volumes to mount a static HTML artifact into an nginx Pod without an init container or a custom nginx image.
