Kubernetes installations can be complex with multiple runtime dependencies and runtime engines. CRI-O was created to provide a lightweight runtime for Kubernetes which adds an abstraction layer between the cluster and the runtime that allows for various OCI runtime technologies. However you still have the problem of daemon dependencies in your cluster for builds - I.e. if you are using the cluster for builds you still need a Docker daemon.

Enter Buildah. Buildah allows you to have a Kubernetes cluster without any Docker daemon for both runtime and builds. Excellent. But what if things go wrong? What if you want to do troubleshooting or debugging of containers in your cluster? Buildah isn’t really built for that, what you need is a client tool for working with containers and the one that comes to mind is Docker CLI - but then you’re back to using the daemon.

Dieser Artikel gibt meine Motivation für den Bau von Container-Images und die Vorgehensweise wieder und zeigt, wie ich mit Buildah meine OCI-kompatiblen Container-Images erstelle.

Es handelt sich dabei mehr um einen Erfahrungsbericht als ein Tutorial und ich erhebe keinen Anspruch auf Vollständigkeit. Das behandelte Beispiel ist jedoch zum Einstieg und zur Nachahmung für all jene geeignet, die Container ausführen können und diese gerne ohne Verwendung von Containerfiles bauen möchten.

Docker can build images automatically by reading the instructions from a Dockerfile. A Dockerfile is a text document that contains all the commands a user could call on the command line to assemble an image. Using docker build users can create an automated build that executes several command-line instructions in succession.

This page describes the commands you can use in a Dockerfile. When you are done reading this page, refer to the Dockerfile Best Practices for a tip-oriented guide.

Rootless containers refers to the ability for an unprivileged user to create, run and otherwise manage containers. This term also includes the variety of tooling around containers that can also be run as an unprivileged user. The goal of this website is to catalogue all of the open questions and unresolved issues that need to be solved to bring us closer to rootless containers “for all”.

“Unprivileged user” in this context refers to a user who does not have any administrative rights, and is “not in the good graces of the administrator” (in other words, they do not have the ability to ask for more privileges to be granted to them, or for software packages to be installed).

Project Atomic is an umbrella for many projects related to re-designing the operating system around principles of "immutable infrastructure", using the LDK (Linux, Docker, Kubernetes) stack.

Many of the components of Project Atomic are upstream components of OpenShift Origin v3.

The primary building block of Project Atomic is the "Atomic Host", a lightweight container OS which implements these ideas. Atomic Hosts are immutable, since each is imaged from an upstream repository, supporting mass deployment. Applications run in containers. Atomic Host versions based on CentOS and Fedora are available, and there is also a downstream enterprise version in Red Hat Enterprise Linux.

Welcome to the site for Buildah. This site features announcements and news around Buildah, and occasionally other container tooling news.

The Buildah package provides a command line tool that can be used to

• create a working container, either from scratch or using an image as a starting point
• create an image, either from a working container or via the instructions in a Dockerfile
• images can be built in either the OCI image format or the traditional upstream docker image format
• mount a working container's root filesystem for manipulation
• unmount a working container's root filesystem
• use the updated contents of a container's root filesystem as a filesystem layer to create a new image
• delete a working container or an image
• rename a local container