Project News

Update Kernel arguments on Atomic Host

Users or adminstrators may want to change kernel arguments of Atomic Host for various reasons. Previously, it was hard for the users due to many of the steps involved, and the harmful consequences that can occur if users accidentally make a mistake in the changing process.

In this post, I want to introduce a command (rpm-ostree ex kargs) that allows users to change kernel arguments on Atomic Host. This command simplifies the process of changing kernel arguments. This command also lies beneath rpm-ostree, and because of that, it benefits from many of the cool features from rpm-ostree. One of them is rpm-ostree rollback, which can allow users to undo their old changes they do not want.

Note: This command is still experimental, so if you have seen any unexpected behavior happening, please report an issue to rpm-ostree. This post also requires some knowledge of Atomic Host and rpm-ostree, please bear that in mind when reading this.

Let’s demonstrate some of the options that can be done with this command!

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The Many Ways to Build an OCI Image without Docker

When containers initially made their big splash into the industry via Docker, users were almost required to use the docker CLI and daemon to create and manage their container images. But a lot has happened since then and now it is easier than ever to create a container image without using docker at all, since the Docker image format has been standardized as the OCI Image format.

In this post, we’ll review some of the ways you can create and manage your container images without ever having to start the docker daemon.

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How does Atomic run system containers without Docker Daemon?


In 2016, we started to Containerize the Kubernetes stack, that is to ship all the components as containers as you can see here. But some of those containers like etcd and flanneld must be started before Docker daemon because etcd is the cluster state store, and flanneld is the cluster network overlay (SDN).

In this blog post we are going to demonstrate how to use the same components used by Project Atomic in the so called system containers that is to run the containers without a Docker daemon, namely: skopeo, ostree, and an OCI runtime like runc or bubble wraps and its OCI wrapper.

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Building a Buildah container image for Kubernetes

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Building a Buildah Container Image for Kubernetes


Dan Walsh (@rhatdan) asked me to look into building a working Buildah container image. This was not just a cool experiment. It has a real purpose. As many readers know, Dan is not a fan of big fat daemons. This has become less of an issue when running containers in Kubernetes as there is an alternative with CRI-O. CRI-O provides kubernetes a standard interface to OCI compliant runtimes. runC is the reference implementation of the OCI runtime specification. Kubernetes calls the runtC runtime through CRI-O and runC then talks to the Linux kernel to run a container. This bypasses the need for the Docker daemon, and containerd. With CRI-O, there is no requirement for the Docker daemon for a kubernetes cluster to run containers.

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Fedora 27 Atomic Host February 28th Release

Fedora Atomic Host 27.93 is available. We have a new kernel (4.15), ostree, and rpm-ostree in this release.

It is also worth noting that now the rpm-ostree status output will prefix the remote:ref with ostree:// in order to denote the system is following an ostree repository remote (see example below). This is in preparation of some upstream changes related to rpm-ostree rojig, where updates can be delivered via a special rpm in a yum repo rather than an ostree server/remote.

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