Has anybody already done any writeups on the process to get a FC5 Xen0 moved to FC6? I''ve been running a semi-production Fedora+Xen rig since FC4. The last transition (FC4/Xen2 - FC5/Xen3pre) was pretty much a PITA and this next step seems to be more of the same so I''d like to help out by documenting it as I run through it. Regards, --Tony Coffman
On Wed, 2006-11-01 at 15:18 -0500, Tony Coffman wrote:> Has anybody already done any writeups on the process to get a FC5 Xen0 > moved to FC6? > > I''ve been running a semi-production Fedora+Xen rig since FC4. The last > transition (FC4/Xen2 - FC5/Xen3pre) was pretty much a PITA and this next > step seems to be more of the same so I''d like to help out by documenting > it as I run through it.If you don''t have anything running in dom0, shouldn''t it be fairly straight forward? Assuming that you''re using LVM for your domU(s): 1. Backup domU(s) 2. Backup domO 3. Install FC6 (leave domU(s) alone) 4. Boo with xen kernel 5. Edit domU configs so that "kernel" and "ramdisk" point to the new kernel. 6. Boot domU(s) My domO used to be a RHEL 4 box running the xen packages from xensource. I converted it to a FC5 box earlier this year. It was painless. The domUs came up right away. Of course, my setup is fairly simple. Right now, I have three domUs, and one bridge. I''d be interested in hearing exactly what problems you had when you made the switch from FC4 to FC5. Regards, Ranbir -- Kanwar Ranbir Sandhu Linux 2.6.17-1.2187_FC5 i686 GNU/Linux 19:18:51 up 3 days, 13:48, 3 users, load average: 0.55, 0.60, 0.62
Kanwar Ranbir Sandhu wrote:> If you don''t have anything running in dom0, shouldn''t it be fairly > straight forward? Assuming that you''re using LVM for your domU(s): > > 1. Backup domU(s) > 2. Backup domO > 3. Install FC6 (leave domU(s) alone) > 4. Boo with xen kernel > 5. Edit domU configs so that "kernel" and "ramdisk" point to the new > kernel. > 6. Boot domU(s) > > My domO used to be a RHEL 4 box running the xen packages from xensource. > I converted it to a FC5 box earlier this year. It was painless. The > domUs came up right away. > > Of course, my setup is fairly simple. Right now, I have three domUs, > and one bridge. > > I''d be interested in hearing exactly what problems you had when you made > the switch from FC4 to FC5. > > Regards, > > Ranbir >Thanks for your response. I suppose I''m little bit of a neatnik. I like to have my domU kernels installed into both the dom0 and into the domU. I install them into the domU so that I don''t have to manually copy modules into the domU everytime I make a kernel change. With your process above how do you handle the absence of the xennet kernel module in your domU''s? Or did you just upgrade the domU''s at the same time? I do use LVM for guests and there is nothing running in dom0. Since FC6 DomU kernel won''t run on FC5 dom0 I''m thinking about one of these approaches Approach A - Upgrade domU''s first, then upgrade dom0 1. Upgrade domU''s to FC6 over time but continue to run an FC5 domU kernel. This requires that I uninstall HAL in the domU''s due to an RPM dependancy requirement but that works for my purposes (simple servers). 2. Upgrade the dom0 to FC6 and then switch my Fedora domU''s to run the FC6 domU kernel Approach B - Upgrade the dom0 first then upgrade the domU''s 1. Upgrade (or perform a parallel fresh install) of the dom0 with FC6. 2. Run the FC6 domU kernel in all domU''s. This will probably involved copying some kernel modules manually into the filesystem for each domU (xennet and maybe the framebuffer console modules? I haven''t tried this yet so I''m not sure.) 3. Upgrade the domU''s over time to FC6. This whole approach only really deals with Fedora domU''s. I have a few others guests that I boot occasionally that I leave out of this discussion to keep it focused on the Fedora issues involved. For the FC4 -> FC5 transition I used approach B with great success. I used that because I needed time to get the domU''s migrated on a scheduled basis. It''ll be interesting to see if there are any additional issues. I''m looking forward to XEN ABI and API stability in the future as it should really make some of these issues easier to deal with. Regards, --Tony Coffman
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I''m about to go down the same route. I have FC5 domU''s and I was thinking about trying the in-place upgrade from FC5->FC6 for each domU. Does anybody have any experience with this? I don''t think it would be to bad given that all of my domU''s are console only so no X or anything to deal with. Chris -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.5 (GNU/Linux) iD8DBQFFU09w1ba7yLNz0PERAojdAJ4mYbvkVdSqMji0Mnlz+bAizgE7rACfcJdu xBU/Zb8yPZfrA/K2GXFu/FU=qnjf -----END PGP SIGNATURE-----
On Thu, Nov 09, 2006 at 08:55:29AM -0700, Chris Hirsch wrote:> -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > I''m about to go down the same route. I have FC5 domU''s and I was > thinking about trying the in-place upgrade from FC5->FC6 for each domU. > Does anybody have any experience with this? I don''t think it would be to > bad given that all of my domU''s are console only so no X or anything to > deal with.If you are on x86_64 you shouldn''t see any Xen specific proiblems with doing upgrades. i386 is a little more complicated though because we switched from non-PAE to PAE in the Xen kernels - so if you were to upgrade your host without first preparing your guests you''ll be unable to boot the guests after the upgrade. The solution is fairly simple though - the latest FC5 errata also provides a ''kernel-xen'' RPM which is PAE enabled. So before upgrading your host, just make sure you have done ''yum install kernel-xen'' in each of your guests. This will let your FC5 guests contonue working on an FC6 host - you can then upgrade your guests to FC6 at will. Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
On Thu, 2006-11-09 at 16:03 +0000, Daniel P. Berrange wrote:> The solution is fairly simple though - the latest FC5 errata also provides a > ''kernel-xen'' RPM which is PAE enabled. So before upgrading your host, just > make sure you have done ''yum install kernel-xen'' in each of your guests. > This will let your FC5 guests contonue working on an FC6 host - you can then > upgrade your guests to FC6 at will.I don''t understand this. Why does kernel-xen have to be installed in the guest? Doesn''t the guest just use the xen kernel running in dom0? I''m obviously missing something here. Regards, Ranbir -- Kanwar Ranbir Sandhu Linux 2.6.17-1.2187_FC5 i686 GNU/Linux 19:42:26 up 11 days, 14:10, 3 users, load average: 0.54, 0.64, 0.56
On Thu, Nov 09, 2006 at 07:47:09PM -0500, Kanwar Ranbir Sandhu wrote:> On Thu, 2006-11-09 at 16:03 +0000, Daniel P. Berrange wrote: > > The solution is fairly simple though - the latest FC5 errata also provides a > > ''kernel-xen'' RPM which is PAE enabled. So before upgrading your host, just > > make sure you have done ''yum install kernel-xen'' in each of your guests. > > This will let your FC5 guests contonue working on an FC6 host - you can then > > upgrade your guests to FC6 at will. > > I don''t understand this. Why does kernel-xen have to be installed in > the guest? Doesn''t the guest just use the xen kernel running in dom0? > I''m obviously missing something here.It doesn''t *have* to be installed in the guest - that''s just way we deal with it in Fedora. The overriding strategy for Xen in Fedora is that we want to make installing, upgrading, managing the operating system in a guest a close to what you do on bare metal as possible[1] - so all your existing Linux knowledge still applies - this makes it easier for people who don''t know Xen to get started. Basically the way it works is thus: - In the guest OS a regular rpm install of the kernel-xen is done. So a regular grub config is written to the boot sector of the virtual disk pointing to the kernel inside the image. - When booting the guest from Dom0, we run ''pygrub'' which pulls the grub config from the DomU filesystem & uses that to extract the guest kernel to a temporay file /var/lib/xen - The DomU is then booted off the temp file in /var/lib/xen So, yes for the actual boot process the kernel is located in Dom0. The other nice thing about this is that the DomU it self contained - you can move the filesystem image anywhere & no have to worry about carting around a separate kernel image file to go with it. Then again, some people may like to have a single kernel image in the Dom0 whcih they use to boot all their guest images. If you want to manage your guests that way, simply add the ''kernel=/foo/bar/wizz'' parameter to the guest config, and remove the pygrub config option. Dan. [1] Other examples.... - using regular Anaconda for installing the DomU rather than fragile install into a chroot shell scripts other distro use. - adding the paravirt framebuffer to Xen so you have a fully graphical console -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
Daniel P. Berrange wrote:> Then again, some people may like to have a single kernel image in the Dom0 > whcih they use to boot all their guest images. If you want to manage your > guests that way, simply add the ''kernel=/foo/bar/wizz'' parameter to the > guest config, and remove the pygrub config option.Quick note: This assumes a statically linked kernel. You still have to install the matching kernel modules into the guest filesystem, and IMHO the easiest way to do that is to just install the kernel package that contains them. I really believe that for the average setup that pygrub is a great time saver. I just wish it were finished and had some of the missing features that grub has (IE: ability to on-the-fly edit a config and boot, which avoids having to fiddle with the Xen config in order to go into single user mode. -- Russell McOrmond, Internet Consultant: <http://www.flora.ca/> Please help us tell the Canadian Parliament to protect our property rights as owners of Information Technology. Sign the petition! http://www.digital-copyright.ca/petition/ict/ "The government, lobbied by legacy copyright holders and hardware manufacturers, can pry my camcorder, computer, home theatre, or portable media player from my cold dead hands!"
On Fri, Nov 10, 2006 at 12:50:48PM -0500, Russell McOrmond wrote:> Daniel P. Berrange wrote: > >Then again, some people may like to have a single kernel image in the Dom0 > >whcih they use to boot all their guest images. If you want to manage your > >guests that way, simply add the ''kernel=/foo/bar/wizz'' parameter to the > >guest config, and remove the pygrub config option. > > Quick note: This assumes a statically linked kernel. You still have to > install the matching kernel modules into the guest filesystem, and IMHO > the easiest way to do that is to just install the kernel package that > contains them. > > I really believe that for the average setup that pygrub is a great > time saver. I just wish it were finished and had some of the missing > features that grub has (IE: ability to on-the-fly edit a config and > boot, which avoids having to fiddle with the Xen config in order to go > into single user mode.Urm, you can already do that. xm create -c foo Will popup the familiar grub menu - select an entry, press ''e'' to edit it, append ''S'', and then boot - just as with regular grub. Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|
Daniel P. Berrange wrote:> Urm, you can already do that. > > xm create -c foo > > Will popup the familiar grub menu - select an entry, press ''e'' to edit > it, append ''S'', and then boot - just as with regular grub.Thank you. I didn''t test with the recent upgrade of the Xen package that has a new (and much improved) pygrub. This is great, and deals with one of the missing pieces with the previous version. Note: The version of pygrub from xen-3.0.2-3.FC5 had a lot of "# FIXME:" comments in it where the edit/etc functions are now in xen-3.0.3-1.fc5. -- Russell McOrmond, Internet Consultant: <http://www.flora.ca/> Please help us tell the Canadian Parliament to protect our property rights as owners of Information Technology. Sign the petition! http://www.digital-copyright.ca/petition/ict/ "The government, lobbied by legacy copyright holders and hardware manufacturers, can pry my camcorder, computer, home theatre, or portable media player from my cold dead hands!"
On Fri, Nov 10, 2006 at 03:12:13PM -0500, Russell McOrmond wrote:> Daniel P. Berrange wrote: > >Urm, you can already do that. > > > > xm create -c foo > > > >Will popup the familiar grub menu - select an entry, press ''e'' to edit > >it, append ''S'', and then boot - just as with regular grub. > > Thank you. I didn''t test with the recent upgrade of the Xen package > that has a new (and much improved) pygrub. This is great, and deals > with one of the missing pieces with the previous version. > > Note: The version of pygrub from xen-3.0.2-3.FC5 had a lot of "# FIXME:" > comments in it where the edit/etc functions are now in xen-3.0.3-1.fc5.Yes, that version of xen from FC5 was really a work-in-progress snapshot of the xen-unstable tree, halfway between 3.0.2 & 3.0.3. Jeremy & others did alot of work to improve pygrub intime for xen 3.0.3 / FC6 Regards, Dan. -- |=- Red Hat, Engineering, Emerging Technologies, Boston. +1 978 392 2496 -=| |=- Perl modules: http://search.cpan.org/~danberr/ -=| |=- Projects: http://freshmeat.net/~danielpb/ -=| |=- GnuPG: 7D3B9505 F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 -=|