Cent 8 as a Xen dom0

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pwnyboy
Posts: 3
Joined: 2020/04/19 18:08:47

Cent 8 as a Xen dom0

Post by pwnyboy » 2020/04/19 18:19:16

I noticed that CentOS no longer maintains a repository of Xen dom0 packages, as is the case with CentOS 7. Assuming that's correct, are there any worthwhile third-party repositories of Xen packages for CentOS 8? Is there another Xen-based platform I should be looking at to ensure long(er) term support, like XCP-NG?

PryMar56
Posts: 17
Joined: 2020/04/20 14:56:31

Re: Cent 8 as a Xen dom0

Post by PryMar56 » 2020/04/20 15:12:24

Hello,

VirtSIG is working on it now, see #centos-virt on Freenode.

I've built the whole C8 virtualization stack 2 ways: xen-4.12.2 + qemu-3.01 and xen-4.13.0 + qemu-4.1.0.
Of course, it all begins with the Xen build, then follows the qemu build, then libvirt, and so on.

Now take a look at the `virt module` that is part of AppStream repo and see that they started with qemu-kvm and
left Xen out of the picture.

Any SRPM that is part of the `virt module` build is effectively out-of-bounds to a Xen stack build unless it is
rebuilt without module tags.

I wrote up more on this here
http://lists.ghettoforge.org/pipermail/ ... 00013.html

I run Xen dom0 in C8 every day, but its using elrepo kernel-ml with python3 and the `virt module` is disabled during build and install.

cheers,
PryMar56

pwnyboy
Posts: 3
Joined: 2020/04/19 18:08:47

Re: Cent 8 as a Xen dom0

Post by pwnyboy » 2020/05/29 03:06:34

Thanks. It appears they (VirtSIG) are in the 'built and testing' phase, as I can now see packages here:

https://buildlogs.centos.org/centos/8/v ... ackages/x/

but not on the public mirrors. Any idea where (and maybe when) completion will be announced, so I can keep checking back without having to read through scroll on IRC?

PryMar56
Posts: 17
Joined: 2020/04/20 14:56:31

Re: Cent 8 as a Xen dom0

Post by PryMar56 » 2020/05/29 15:35:18

if VirtSIG is waiting for the companion libvirt build, then it may take another 6 weeks or more.

Like I mentioned before, the `virt module` is the immovable object, which now requires us to
apply the irresistible force of redesign.

The libvirt build has a BR on /usr/bin/qemu-img. It also has a similar requires for 2 of the subpackages.
This is the spoiler which can and will `throw a wrench into the fan.`

== dnf provides ==
admin@c8xen:~$ sudo dnf provides '/usr/bin/qemu-img'
qemu-img-15:2.12.0-88.module_el8.1.0+248+298dec18.x86_64 : QEMU command line tool for manipulating disk images
Repo : AppStream
Matched from:
Filename : /usr/bin/qemu-img

qemu-img-15:2.12.0-88.module_el8.1.0+258+1d2a1d58.1.x86_64 : QEMU command line tool for manipulating disk images
Repo : AppStream
Matched from:
Filename : /usr/bin/qemu-img

qemu-img-15:2.12.0-88.module_el8.1.0+266+ba744077.2.x86_64 : QEMU command line tool for manipulating disk images
Repo : AppStream
Matched from:
Filename : /usr/bin/qemu-img

qemuu-1:3.0.1+3-1.el8.x86_64 : Qemu upstream runtime environment
Repo : @System
Matched from:
Filename : /usr/bin/qemu-img
== snip provides ==

Notice the 3 */qemu-img provides coming from modules! This is why the VIrtSIG qemu-xen build must provide it too. They can do it
with a symlink. If they don't, then their libvirt builddep will import a module and the whole thing goes out-of-bounds.

Their qemu-xen build also needs this `conflicts`.
admin@c8xen:~$ sudo rpm -qi --conflicts qemuu
Name : qemuu
Epoch : 1
Version : 3.0.1+3
Release : 1.el8
Architecture: x86_64
Install Date: Mon 18 May 2020 11:31:34 AM PDT
snip
Source RPM : xen-4.12.3-1.el8.src.rpm
Build Date : Mon 18 May 2020 11:11:22 AM PDT
snip
Description :
This package contains the runtime programs which
form the qemuu part of the core Xen userspace environment.
qemu-img = 15:2.12.0
qemu-kvm-core = 0:4.5.0
qemu-system-x86

Without the provides on */qemu-img and conflicts against the module versions, the `virt module` will stop the whole project.

cheers,
PryMar56

Its done in the qemu-xen spec file.

pwnyboy
Posts: 3
Joined: 2020/04/19 18:08:47

Re: Cent 8 as a Xen dom0

Post by pwnyboy » 2021/06/02 19:18:50

It appears there has been some movement on this, as packages are now being built for Xen 4.15:

https://buildlogs.centos.org/centos/8/v ... ackages/x/

Can anyone tell me how to use these packages, and any potential limitations similar to the ones mentioned above?

PryMar56
Posts: 17
Joined: 2020/04/20 14:56:31

Re: Cent 8 as a Xen dom0

Post by PryMar56 » 2021/06/03 15:28:56

It is still in buildlogs only, without a push into the VirtSIG tree, then

$ cat CentOS-Xen-415.repo
[centos-virt-xen-415]
name=CentOS-$releasever - xen
baseurl=http://mirror.centos.org/centos/$releas ... ch/xen-415
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-SIG-Virtualization

[centos-virt-xen-415-testing]
name=CentOS-$releasever - xen - testing
baseurl=http://buildlogs.centos.org/centos/$rel ... ch/xen-415
gpgcheck=0
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-SIG-Virtualization

-- snip --

<mock-chroot> sh-4.4# dnf list available --disablerepo=\* --enablerepo=centos-virt-xen-415-testing
CentOS-8 - xen-4.15 - testing 3.9 kB/s | 3.0 kB 00:00
Available Packages
qemu-xen.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-devel.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-doc.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-hypervisor.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-libs.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-licenses.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-livepatch-build-tools.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-ocaml.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-ocaml-devel.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing
xen-ovmf.x86_64 202102-1.gitef91b07388e1.el8 centos-virt-xen-415-testing
xen-runtime.x86_64 4.15.0-1.el8 centos-virt-xen-415-testing

<mock-chroot> sh-4.4# dnf info xen-runtime --disablerepo=\* --enablerepo=centos-virt-xen-415-testing
CentOS-8 - xen-4.15 - testing 5.7 kB/s | 3.0 kB 00:00
Available Packages
Name : xen-runtime
Version : 4.15.0
Release : 1.el8
Architecture : x86_64
Size : 3.5 M
Source : xen-4.15.0-1.el8.src.rpm
Repository : centos-virt-xen-415-testing
Summary : Core Xen runtime environment
URL : https://www.xenproject.org/
License : GPLv2+ and LGPLv2+ and BSD
Description : This package contains the runtime programs and daemons which
: form the core Xen userspace environment.

cheers,
PryMar56

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