Am Donnerstag, den 25.01.2007, 17:01 +0000 schrieb Karanbir Singh: > Nils Toedtmann wrote: > > there is a demand for ready-to-boot virtual machine images for distros > > like CentOS. Since i am an afinicado of CentOS and Xen, i would like to > > build and maintain a CentOS5-image. [snip] > > RoadMap: > > > > * wait for CentOS5-beta2 ;-) > > Why ? > > CentOS-4 is in quite a decent shape to make it into VM's and _lots_ > people are going to want VM's for CentOS-3 [...] I agree. But customization of C4 (and probably C3, too) to run smoothly as a VM is a bit evil (i run a bunch of productive C4 DomUs, so walked through that valley ...): glibc and db4 have to be patched/rebuilt because of NPTL incompatibilities. For glibc there is the ugly workaround to blackhole /lib/tls. But you have to make sure that glibc-updates do not fill /lib/tls again. For db4 there is no other option than rebuild it with other compiletime options. I know at least one application (cyrus-imapd) which does not run on a C4-VM with standard db4. Unfortunately i am not a coder. So i can (and did) blackhole TLS-libs and rebuild db4 - without exactly knowing what i'm doing! That WorksForMe[tm] (uptimes > 1year), but probably won't meet CentOS quality standards. So without the help of the glibc- and db4-maintainers, i could only provide C4-images of questionable quality. Btw: pointing virt-install to a C4-repo won't avoid that problem. > One of the things on the ToDo list here is a document for a known > process to help with this migration -> Move a C3/C4 machine into a VM > under C5, so that your C3/C4 apps remain supported and function as they > do now, while still getting the added benefit of C5 on the host. I am willing to write a migration guide. Besides the NPTL problem, migration of a headless server native->VM should be fairly easy: 1) install a kernel-xen-*.rpm into C4 (to get the necessary LKMs) 2) build an initrd in C4 and copy it to C5 3) write a /etc/xen/C4 config file. Map all blockdevs the native C4 has used to virtual /dev/sd*: disk = ['phy:,VolGroup00/C4_root,sda1,w', ... ] and adjust C4's /etc/fstab to that mapping. 5) "xm create -c C4" I could provide a customized DomU-kernel with static xen-{blk,net}- support, obsoleting (1) and (2). The main prob would be the C4 complaining about changed HW (particularly if it runs kudzu): your tape-roboters, raid-controllers etc are gone, you probably want to switch from local X to vnc- or rdp-server, ... > > * create and post a minimal CentOS5-beta2 i386 image with xen- and > > vmware configs, wait for reviews/bugreport > > * create and post a standard desktop CentOS5-beta2 i386 image, wait > > for reviews/bugreport > > Once there is a basic setup and required infrastructure in place, doing > roles is just a question of adding some more details to scripts etc, I > am sure there are many roles we can address like this. Sure (i hope i know what you mean with "role"). Could be done by empty meta-packages like ubuntu's "{,k,x}ubuntu-desktop". > > * if there are enough positive reports, repeat for CentOS5-final > > We are really not interested in doing / spending time on something that > is not going to be there for CentOS-5/Release - so if you are getting > involved, do so with the intent of seeing this through. Now my english is drained - You mean i shall do it for C5/release unconditionally ;-? OK > > * release when/if centos.org is pleased with the (bugfixed) images > > yes, we have a QA team now! > > > Are you interested in such a project? I am eager for comments. > > You have my attention and I am happy to push this along from the inside, > but if we are going to do this - lets try and cover the spectrum, not > just focus on C5 ( specially taking on board what Daniel has said, C5 > VM's are trivial once you have the C5 host running ) Don't forget all those not using CentOS - yet! > One (of the many) places where users are going to see really good > benefit is when we can provide some alternatives to move their C3 / C4 > machines into. > > Still interested ? Yes. But either you have to accept poor glibc/db4-hacks for C4 (and maybe C3), or we need support from CentOS' glibc/db4-maintainers. Still interested? (SCNR) Regard, /nils.