Focused hands-on problems designed to help you hone your DevOps or Server Side skills. Some challenges are more educational, while others are based on real-world scenarios. The platform provides hints and feedback for each challenge, including automated solution checks.
Learn how to build and publish an uncompressed container image - a helpful trick to optimize disk I/O for large images, especially when you can benefit from a fast internal network.
In this challenge, you will practice installing and configuring containerd: obtaining the release binaries, placing them in the correct locations, adding the container runtime and CNI plugins to the system, and starting a container with full networking support.
Learn how to build a secure, lightweight, and production-ready container image for a statically linked Go application by following this hands-on challenge full of practical tips and tricks.
Learn how to build a secure, lightweight, and production-ready Node.js container image for a SvelteKit application by following this hands-on challenge full of practical tips and tricks.
Learn how to build a secure, lightweight, and production-ready Node.js container image for a Nuxt application by following this hands-on challenge full of practical tips and tricks.
Can you make a container exit gracefully after the 'docker stop' command while preserving its extensible entrypoint mechanism?
This challenge focuses on debugging memory usage issues in a Go application deployed in a Kubernetes cluster. The goal is to ensure the application can handle moderate traffic without crashing, even when it runs with significantly constrained memory resources.
Learn how to build a secure, lightweight, and production-ready Node.js container image for a Next.js application by following this hands-on challenge full of practical tips and tricks.
Learn how to copy all image tags from one repository to another in an efficient way.
Learn how to copy a multi-platform image from one repository to another using the docker manifest command or other, more convenient, tools like crane, skopeo, or regctl.
Learn how to copy a container image from one repository to another without using Docker, Podman, or any other container runtime.
Learn how to fine-tune the container's cgroup to make the container exit when one of its processes runs out of memory.
Run a multi-container Docker Compose application limiting its total CPU and memory usage without specifying the individual container's limits.
Learn how to set up a cgroup v2 to make the OOM killer terminate the entire process group when one process goes out-of-memory.
Prove your SRE skills - identify and stop an overloaded container, then start a new one with limited CPU and RAM resources.
Learn how to write a Dagger Function to run the unit test suite of a Go project.
Learn how to write a Dagger Function to build a multi-arch Go project.
Can you unpack the filesystem of a container image into a local directory?
Can you edit a file in a running container? What if there is no shell?
Learn on practice the limitations of FROM scratch images and the ways to mitigate them.
Be a networking Sherlock Holmes - find out which port a Kubernetes app uses and send a request to it.
Learn how to send a signal to a Kubernetes app running in a container without shell.
Can you start a container using the default containerd CLI, ctr? Knowing how to use ctr may come in handy when you need to debug lower-level container issues.
Prove your networking skills by setting up an improvised proxy server with netcat.
Prove your Linux networking skills by connecting two network namespaces with a virtual Ethernet device.
There is a container that seems to have access to all host's interfaces but for some reason cannot call any addresses outside of the host. Can you fix it?
Learn a trick or two about container image labels and how to read them with ctr.
Learn a bunch of Linux networking tricks while trying to access an Nginx server running inside a Docker container with no published ports.
Can you find a way to execute a command in a Docker container using ctr?
Identify what causes the Pod initialization to fail and fix it while keeping the Pod images unchanged.
Identify what causes the Pod initialization to fail and fix it while keeping the Pod images unchanged.