[CentOS-announce] New CentOS Atomic Release and Kubernetes System Containers Now Available

[news 28]

Last week, the CentOS Atomic SIG released an updated version

(https://wiki.centos.org/SpecialInterestGroup/Atomic/Download'>https://wiki.centos.org/SpecialInterestGroup/Atomic/Download) of

CentOS Atomic Host (7.1707), a lean operating system designed to run

Docker containers, built from standard CentOS 7 RPMs, and tracking the

component versions included in Red Hat Enterprise Linux Atomic Host.

 

The release, which came as part of the monthly CentOS release stream,

was a modest one, including only a single glibc bugfix update

(https://lists.centos.org/pipermail/centos-announce/2017-July/022505.html).

The next Atomic Host release will be based on the RHEL 7.4 source code

(https://seven.centos.org/2017/08/centos-linux-7-1708-based-on-rhel-7-4-source-code/)

and will include support for overlayfs container storage, among other

enhancements.

 

Outside of the Atomic Host itself, the SIG has updated its Kubernetes

container images to be usable as system containers

(http://www.projectatomic.io/blog/2016/09/intro-to-system-containers/'>http://www.projectatomic.io/blog/2016/09/intro-to-system-containers/).

What's more, in addition to the Kubernetes 1.5.x-based containers that

derive from RHEL, the Atomic SIG is now producing packages and

containers that provide the current 1.7.x version of Kubernetes.

 

## Containerized Master

 

The downstream release of CentOS Atomic Host ships without the

kubernetes-master package built into the image. You can install the

master kubernetes components (apiserver, scheduler, and

controller-manager) as system containers, using the following

commands:

 

 

# atomic install --system --system-package=no --name kube-apiserver

registry.centos.org/centos/kubernetes-apiserver:latest

 

# atomic install --system --system-package=no --name kube-scheduler

registry.centos.org/centos/kubernetes-scheduler:latest

 

# atomic install --system --system-package=no --name

kube-controller-manager

registry.centos.org/centos/kubernetes-controller-manager:latest

 

 

## Kubernetes 1.7.x

 

The CentOS Virt SIG is now producing Kubernetes 1.7.x rpms, available

through this yum repo

(https://github.com/CentOS/CentOS-Dockerfiles/blob/master/kubernetes-sig/master/virt7-container-common-candidate.repo).

The Atomic SIG is maintaining system containers based on these rpms

that can be installed as as follows:

 

### on your master

 

 

# atomic install --system --system-package=no --name kube-apiserver

registry.centos.org/centos/kubernetes-sig-apiserver:latest

 

# atomic install --system --system-package=no --name kube-scheduler

registry.centos.org/centos/kubernetes-sig-scheduler:latest

 

# atomic install --system --system-package=no --name

kube-controller-manager

registry.centos.org/centos/kubernetes-sig-controller-manager:latest

 

 

### on your node(s)

 

 

# atomic install --system --system-package=no --name kubelet

registry.centos.org/centos/kubernetes-sig-kubelet:latest

 

# atomic install --system --system-package=no --name kube-proxy

registry.centos.org/centos/kubernetes-sig-proxy:latest

 

 

Both the 1.5.x and 1.7.x sets of containers have been tested with the

kubernetes ansible scripts

(https://github.com/kubernetes/contrib/tree/master/ansible) provided

in the upstream contrib repository, and function as drop-in

replacements for the installed rpms. If you prefer to run Kubernetes

from installed rpms, you can layer the master components onto your

Atomic Host image using rpm-ostree package layering with the command:

`atomic host install kubernetes-master`.

 

The containers referenced in these systemd service files are built in

and hosted from the CentOS Community Container Pipeline

(https://wiki.centos.org/ContainerPipeline), based on Dockerfiles from

the CentOS-Dockerfiles repository

(https://github.com/CentOS/CentOS-Dockerfiles/tree/master/kubernetes).

 

## Download CentOS Atomic Host

 

CentOS Atomic Host is available as a VirtualBox or libvirt-formatted

Vagrant box, or as an installable ISO, qcow2 or Amazon Machine image.

For links to media, see the CentOS wiki

(https://wiki.centos.org/SpecialInterestGroup/Atomic/Download).

 

## Upgrading

 

If you're running a previous version of CentOS Atomic Host, you can

upgrade to the current image by running the following command:

 

 

$ sudo atomic host upgrade

 

 

## Release Cycle

 

The CentOS Atomic Host image follows the upstream Red Hat Enterprise

Linux Atomic Host cadence. After sources are released, they're rebuilt

and included in new images. After the images are tested by the SIG and

deemed ready, we announce them.

 

## Getting Involved

 

CentOS Atomic Host is produced by the CentOS Atomic SIG

(http://wiki.centos.org/SpecialInterestGroup/Atomic), based on

upstream work from Project Atomic (http://www.projectatomic.io/). If

you'd like to work on testing images, help with packaging,

documentation -- join us!

 

The SIG meets weekly on Thursdays at 16:00 UTC in the #centos-devel

channel, and you'll often find us in #atomic and/or #centos-devel if

you have questions. You can also join the atomic-devel

(https://lists.projectatomic.io/mailman/listinfo/atomic-devel) mailing

list if you'd like to discuss the direction of Project Atomic, its

components, or have other questions.

 

## Getting Help

 

If you run into any problems with the images or components, feel free

to ask on the centos-devel