Lars Kurth (standing in for George Dunlap)Lead CentOS Virtualization SIG

Community Manger, Xen Project

Chairman, Xen Project Advisory Board lars_kurth

Community-oriented distrosDebian, Gentoo, BSDs

Enterprise targeted distrosRedHat, SuSE

Company-sponsored community distrosFedora, OpenSuSE

Company-patched community distroUbuntu

Community-rebuilt distrosCentOS, Scientific Linux

Mcamcamca @ Flickr

StabilityUse old versions

Backport significant new functionality / bug fixes

SupportabilityDon’t try to support everything

Pick one technology and support that one well

Eliminate all non-supported technologies

Community-rebuilt distro...with a twist

SIG =Special Interest Group

Released 10 July 2011

6 months after the release 10000’s of users still using CentOS 5

The reason? Xen Project

RHEL had purchased Qumranet

Made KVM the hypervisor of choice for RHEL6

Tons of users who still wanted to use Xen

CentOS community members approached the Xen Community

At FOSDEM 2012, we started to make a plan to fix this

Supplementary yum repo

Xen

Domain 0 kernel

libvirt

What if people want all the boring, slow-changing stability of an enterprise kernel, except...

...for one application, where they want something newer?

...a different technology than the one chosen by the “commercial upstream”?

Community-developed “patches” on the immutable core

Mechanism:Additional yum repo that adds / overrides core packages

General approach: Make it up as we go along

Mcamcamca @ Flickr

SIGs Approved:

Cloud SIG (OpenStack, &co )

Cloud Instance SIG (Amazon instances, &c)

Virtualization (Xen, Docker, oVirt)

Storage (CentOS as a storage node)

Atomic

... it would seem so!

Maria Ly @ Flickr

Issues we have worked through

in the last 12 months

Some are not yet fully resolved

Moving from a small tight-knit group to larger disaggregated groups

Everyone’s trusted to Want to trust everyone, but trust needs to be limited

Not unique to CentOS model

Complicated by the already-large community

Also See:

cbs.centos.org/koji/wiki.centos.org/HowTos/CommunityBuildSystemCERN CentOS Dojo presentation @ bit.do/centos-sig-cbs

Not even minor fixes can be added to the CentOS-Core

So even minor changes mean re-building the whole package

Example: virt-install uses blktap1 instead of blktap2

Re-building also means tracking Core changes

Nicholas A. Tonelli @ Flickr

Example:Docker for C7 (in the Virt SIG) uses stock C7 kernel

Xen for C7 will need a domain-0 enabled kernel

Solutions:Break down into virt7-xen and virt7-docker reposShare the same SIG delivered kernel

Challenge: Avoiding repo multiplication

Mcamcamca @ Flickr

What if you want to install two different SIGs, but:

The two SIGs require different versions of the same package (e.g., the kernel)

General approach:

We’ll figure it out when we get there.

Mcamcamca @ Flickr

CentOS core has the stability guarantees of the upstream enterprise OS

CentOS SIGs don’t have nearly as much testing behind them

But they still carry the CentOS name

Oversight by CentOS board member important

Maintainers having taken ownership for several technologies: Xen, Docker, oVirt

wiki.centos.org/SpecialInterestGroup/Virtualization

Done:Projects building in the community build system for CentOS 6

Updated to Xen 4.4.1 and libvirt 1.2.10

Already a user: “yum update”wiki.centos.org/HowTos/Xen/Xen4QuickStart

To-do:Build for CentOS 7

Update kernel to 3.14 (currently 3.10)

Docker 1.4.1 for CentOS 7 in CBS

Close to release (in testing, tag “virt7-testing”)

Working on Rocket

Added to Virt SIG 6 weeks ago

Goals:Build qemu-kvm binary with live snapshot supportoVirt Live “spin”

oVirt Node “spin”

Interface with Storage SIG … for GlusterFS support

See if there’s an existing SIG you can join

E-mail centos-devel with your proposal

Convince one of the CentOS Board members to sponsor you.

wiki.centos.org/SpecialInterestGroupwww.centos.org/about/governance/sigs

Slides on www.slideshare.net/xen_com_mgr/