A new CentOS Atomic Host release (7.20170117), based on CentOS 7.1611, is now available. Beyond the rebase to the new CentOS version, the biggest change in this release is the removal of the kubernetes-master package from the image, a change that we’ve inherited from RHEL Atomic.
You can run the master kubernetes components (apiserver, scheduler, and controller-manager) in containers, managed via systemd, using the service files and instructions on the CentOS wiki. [1] The containers referenced in these systemd service files are built in and hosted from the CentOS Community Container Pipeline [2], based on Dockerfiles from the CentOS-Dockerfiles repository. [3]
[1] https://wiki.centos.org/SpecialInterestGroup/Atomic/ContainerizedMaster [2] https://wiki.centos.org/ContainerPipeline [3] https://github.com/CentOS/CentOS-Dockerfiles/tree/master/kubernetes
I’ve tested these containers with the kubernetes ansible scripts provided in the upstream contrib repository [4], and they work as expected, provided you first copy the service files onto your master. I’ve also tested the containers with a cluster already running kubernetes as configured by the ansible scripts, and that case works as well.
[4] https://github.com/kubernetes/contrib/tree/master/ansible
There is, however, an SELinux issue [5], the workaround for which is running your kubernetes nodes in permissive mode. The fix for this issue requires updating to the docker 1.12 version released this week as part of this week’s RHEL AH 7.3.2. As soon as docker and the rest of the “atomic” packages are built for CentOS, we’ll test and release an updated CentOS Atomic Host, along with refreshed media.
[5] https://bugzilla.redhat.com/show_bug.cgi?id=1412803
For now, if you wish to upgrade to 7.20170117, do so by running:
# atomic host upgrade
If you aren't already running CentOS Atomic, you can download an image from our download page on the CentOS wiki and upgrade that to the latest tree. [6]
[6] https://wiki.centos.org/SpecialInterestGroup/Atomic/Download
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CentOS Atomic Host 7.20170117 includes these core component versions:
* atomic-1.13.8-1.el7.x86_64 * cloud-init-0.7.5-10.el7.centos.1.x86_64 * docker-1.10.3-59.el7.centos.x86_64 * etcd-2.3.7-4.el7.x86_64 * flannel-0.5.5-1.el7.x86_64 * kernel-3.10.0-514.2.2.el7.x86_64 * kubernetes-node-1.3.0-0.3.git86dc49a.el7.x86_64 * ostree-2016.11-2.atomic.el7.x86_64