Blog.CentOS.org

Happy birthday, CentOS!

15 years ago, the CentOS project started up in order to fill a gap left by a change in the way that Red Hat decided to market their product.

Many of the people that were involved in those early days are still involved today, although in different capacities than they were then. Over they years, their involvement has changed, due to their own changing job responsibilities, as well as the shifting technological landscape.

Over the next few months, as part of our celebration of our 15 year anniversary, I'm going to be talking with some of these people that were involved in the early days, as well as some that have joined later on, to talk about how and why people get involved in this project.

If you would like to tell your story, please get in touch with me at rbowen@centosproject.org and we'll schedule an interview.

Purpose

Xen 4.10.2 is also available, and the dom0-enabled Linux kernel is at 4.9.127. Release candidate builds of Xen 4.12 are also available.

In this post, we're going to talk about how to use buildah to build container images on CentOS.

buildah is a command line tool that facilitates building OCI compliant images. There's a plethora of information available around what buildah is on its GitHub landing page so we won't dive more into what it is. However, it's worth mentioning that buildah helps you build container images without having to run any daemon in the background, unlike the docker CLI tool which requires the Docker daemon to be running in the background.

Installing buildah

buildah is already available in the CentOS repos. All we need to do is:

$ yum install -y buildah
$ buildah -v
buildah version 1.5-dev (image-spec 1.0.0, runtime-spec 1.0.0)

buildah offers a number of features and options. To know about these, simply execute buildah on the command line or refer to its manual page (man buildah).

Building the container image

buildah can build a container image by referring the same Dockerfile that docker build refers to. Let's consider this simple Dockerfile for example. All it does is install the wget package:

$ cat Dockerfile
FROM registry.centos.org/centos/centos

RUN yum install -y wget && yum clean all

Now, build the container image named wget :

$ buildah bud -t wget .
$ buildah images
IMAGE ID             IMAGE NAME                                               CREATED AT             SIZE
2f254a4fff8d         registry.centos.org/centos/centos:latest                 Dec 17, 2018 05:07     210 MB
9b6563cfaff2         localhost/wget:latest                                    Jan 16, 2019 11:01     234 MB

You can use this container image with podman by doing:

$ podman run -it --rm wget bash

podman is a tool for managing pods, containers, and container images. Its website contains extensive detail about its capabilities and uses.

Use the container image with Docker

buildah also makes it possible to use the image thus built via the local Docker daemon. It's as simple as doing a buildah push:

$ docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE

$ buildah images
IMAGE ID             IMAGE NAME                                               CREATED AT             SIZE
2f254a4fff8d         registry.centos.org/centos/centos:latest                 Dec 17, 2018 05:07     210 MB
9b6563cfaff2         localhost/wget:latest                                    Jan 16, 2019 11:01     234 MB

$ buildah push wget:latest docker-daemon:registry.centos.org/centos/wget:latest
Getting image source signatures
Copying blob sha256:b05580fca2f9aabb2d8fa975b29146c9147c8418e559f197c54a4fac04babb95
 200.47 MiB / 200.47 MiB [==================================================] 4s
Copying blob sha256:fa5e7b9f8f4d8f07f7af27cd06269ba16ba0f06cbacacc7c7e96a616da885cab
 22.82 MiB / 22.82 MiB [====================================================] 0s
Copying config sha256:9b6563cfaff28baa1075e86b60c502f85fc31b56bdb641d314a7c61d2e91fae8
 1.33 KiB / 1.33 KiB [======================================================] 0s
Writing manifest to image destination
Storing signatures
Successfully pushed registry.centos.org/centos/wget:latest@sha256:66f4c1c8378c7d9e22a0d3c9a0943739082dfeae3344e5f2b069e9c9ddf08271

$ docker images
REPOSITORY                        TAG                 IMAGE ID            CREATED             SIZE
registry.centos.org/centos/wget   latest              9b6563cfaff2        6 minutes ago       226 MB

Initially, the local Docker daemon storage had no container images. We did buildah push wget:latest docker-daemon:registry.centos.org/wget:latest to push the image to local Docker daemon's storage. Now doing docker images shows the image and can then be used with docker run

That's it

In this blog, we saw simple steps that need to be performed to install and use buildah to build OCI images which can then be pushed to local Docker daemon's storage. buildah can also push container images to the remote registry. It is highly recommended to read the documentation to know about more features and capabilities of buildah.

In a future blog, we will share how the CentOS Container Pipeline team managed to build container images on OpenShift using buildah.

On Friday of last week, we once again gathered in Brussels for our annual CentOS Dojo at FOSDEM.

14 speakers gave talks on a wide variety of topics, ranging from deeply technical, to community-centered, to a vision of what's coming in CentOS 8. The full schedule is on the event website, and the videos from the event will be posted on YouTube as soon as we can possibly get them up.

We had roughly 90 people in attendance at this event, which was about the same as last year.

At lunch time, we celebrated CentOS's 15th birthday with a lovely birthday cake.

(More pictures here.)

If you missed us in Brussels, don't worry. We have lots of other events coming up.

If you would like to host a Dojo, or have a suggestion of where we should run on, please don't hesitate to get in touch with us on the CentOS-Promo mailing list.

NFV SIG Quarterly Report through February 1st, 2019

Purpose

The CentOS NFV  SIG exists to support Network Function Virtualization (NFV) in CentOS. Specifically, the idea is to be a vehicle to provide packages for implementers of software networks on the CentOS platform.

Membership Update

In this reporting period, we have had little formal participation. However, there has been continued in NFV on CentOS and interest in deploying our packages on CentOS. We are always looking for additional community participation in all aspects of this SIG, including promoting, building releasing other packages for NFV.

Anyone interested in participating in the NFV SIG should subscribe to the generic CentOS mailing list.

Releases and Packages

fd.io VPP

The past quarter has been a slow one in terms of actual delivered packages. Our main active package, VPP has not been released since 1807. Upstream version 1810 requires dev-toolset 7.

However, recently dev-toolset-7 and all prerequisites have been built and-or cross tagged into the NFV SIG common. We are currently in the process of building vpp 19.01 for release and plan to have these packages ready in February.

To install latest release of VPP,

yum install centos-release-fdio

yum install vpp*

Health and Activity

The health of NFV SIG could be better. It was originally perceived as the sponsor for getting OPNFV project into the CentOS distribution. However, subsequently OPNFV releases its own CD images. Subsequently it was primarily sponsoring building opendaylight packages which are still built as part of the upstream product CI.

Since Q1 2018 the project has been focused on building packages and dependencies for upstream fast data plane project, fd.io

including vpp.

At this point, the project is looking for a renewed focus. Perhaps, packages to facilitate containerization and kubernetes. Other ideas and sponsors are welcome.

Also, we have also been working towards several upcoming events.

On February 1st, we will have a presentation about NFV SIG at  CentOS Dojo at FOSDEM, in Brussels.

Issues for the Board

We have no issues to bring to the board’s attention at this time.