The CentOS Atomic SIG has released an updated version (https://wiki.centos.org/SpecialInterestGroup/Atomic/Download) of CentOS Atomic Host (7.1802), a lean operating system designed to run Linux containers, built from standard CentOS 7 RPMs, and tracking the component versions included in Red Hat Enterprise Linux Atomic Host.
This release rolls up all package minor updates that shipped through the month of February, including, most significantly, a newer version of rpm-ostree with support for overriding base packages during package layering operations. (see below for more details)
CentOS Atomic Host includes these core component versions:
* atomic-1.20.1-9.git436cf5d.el7.centos.x86_64 * cloud-init-0.7.9-9.el7.centos.2.x86_64 * docker-1.12.6-71.git3e8e77d.el7.centos.1.x86_64 * etcd-3.2.11-1.el7.x86_64 * flannel-0.7.1-2.el7.x86_64 * kernel-3.10.0-693.17.1.el7.x86_64 * kubernetes-node-1.5.2-0.7.git269f928.el7.x86_64 * ostree-2017.14-2.el7.x86_64 * rpm-ostree-client-2017.11-1.atomic.el7.x86_64
rpm-ostree override
While it's been possible to layer new packages onto the base CentOS Atomic tree for some time now, overriding existing base packages with layered alternatives either wasn't possible or was considered experimental. Version 7.1802 now allows for overriding base packages.
For example, the origin-clients package that includes OpenShift Origin's "oc" tool conflicts with the kubernetes-client package included in the base tree. You can use package layering and overrides to install the openshift-release rpm, remove the conflicting rpms, and install the origin-clients rpm:
# rpm-ostree install centos-release-openshift-origin # rpm-ostree override remove kubernetes-client kubernetes-node -r
# rpm-ostree install origin-clients -r
# oc cluster up Starting OpenShift using openshift/origin:v3.7.0 ... Pulling image openshift/origin:v3.7.0 ...
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:
# 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 every two weeks as part of the Project Atomic community meeting at 16:00 UTC on Monday in the #atomic channel. 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 (http://lists.centos.org/mailman/listinfo/centos-devel) mailing list.
Have questions about using Atomic? See the atomic (https://lists.projectatomic.io/mailman/listinfo/atomic) mailing list or find us in the #atomic channel on Freenode.