XCP-ng 8.3 updates announcements and testing

gduperrey

New update candidates for you to test!

A new batch of non-urgent updates is ready for user tests before a future collective release. Below are the details about these.

Maintenance updates

blktap: Fix a bad integer conversion that interrupts valid coalesce calls on large VDIs. This fixes an error that could occur on VHD coalesces, generating logs on the SMAPI side.
kernel:
- Fix compatibility issues with Minisforum MS-A2 machines. For more information, you can consult this forum post.
- Backport fix for CVE-2020-28374, a vulnerability that is unlikely to be exploitable in XCP-ng, fixed as defence-in-depth.
xapi & xen:
- Add a new /etc/xenopsd.conf.d directory, in which users can add a .conf file with configuration values for xenopsd.
- Patch Xen to support a new option allowing to activate the remapping of grant-tables as Writeback. This fixes a performance issue for Linux Guests on AMD processors. Guests need their kernel to support the feature which enables this fix (Linux distributions that have recent enough kernels or apply fixes from the mainline LTS kernels are OK. Older ones are not. Some currently supported LTS distros don't have the patch yet: RHEL 8 and 9 and their derivatives are not ready yet - no effect on older distros such as Ubuntu 20.04. See partial list below). Windows and *BSD guests were not affected by the performance problem this change solves.
- While we are confident with this change, we decided to make it opt-in at first, so that users be conscious of the change and also know how to revert it if any side effects remain in edge cases. To enable the fix pool-wide, create a file named /etc/xenopsd.conf.d/custom.conf with the following line:
```
xen-platform-pci-bar-uc=false
```
  - Then restart the toolstack on the host: xe-toolstack-restart
  - Then add the configuration and restart the toolstack on every other hosts of the pool
  - Then stop and start VMs so that the setting is applied to them at boot.
- In a future update, this will become the default.
- This is not the end of the way towards better performance on AMD EPYC servers, but it's significant progress!
xo-lite:
- [Host/VM/Dashboard] Fix display error due to inversion of upload and download
- [Sidebar] Updated sidebar to auto close when the screen is small
- [SearchBar] Updated query search bar to work in responsive (PR #8761)
- [Pool,Host/Dashboard] CPU provisioning considers all VMs instead of just running VMs
- For more details, we invite you to read the blog post about the latest Xen-Orchestra update.

OS support for the AMD performance workaround:

Debian: 11 (5.10: TODO), 12 (6.1: OK)
Ubuntu: 20.04 LTS (5.4: EOL), 22.04 LTS (5.15: SOON, HWE 6.8: OK), 24.04 LTS (6.8 & HWE 6.14: OK)
openSUSE Leap, 15.5 (5.14: EOL) 15.6 (6.4: OK)
SUSE Enterprise (LTSS) : SLE15 SP3 - LTSS (5.3: Not upstream), SLE15 SP4/5 - LTSS (5.14: Not upstream), SLE15 SP6+ (OK)
RHEL (+derivates): 8 (4.19: EOL-ish?), 9 (5.14: Not upstream), 10 (6.12: OK)
Fedora: All supported: OK (37+)
Alpine Linux: All supported: OK (v3.18+)

EOL = distro is EOL
Not upstream = not covered by Linux stable project (i.e probably needs discussions with distro)
SOON: Distro needs to update its kernel

Test on XCP-ng 8.3

yum clean metadata --enablerepo=xcp-ng-testing
yum update --enablerepo=xcp-ng-testing
reboot

The usual update rules apply: pool coordinator first, etc.

Versions:

blktap: 3.55.5-2.3.xcpng8.3
kernel: 4.19.19-8.0.38.4.xcpng8.3
xapi: 25.6.0-1.11.xcpng8.3
xen: 4.17.5-15.2.xcpng8.3
xo-lite: 0.13.1-1.xcpng8.3

What to test

Normal use and anything else you want to test.

Test window before official release of the updates

None defined, but early feedback is always better than late feedback, which is in turn better than no feedback

flakpyro

Updated both of my test hosts.

Machine 1:
Intel Xeon E-2336
SuperMicro board.

Machine 2:
Minisforum MS-01
i9-13900H (e-cores disabled)
32 GB Ram
Using Intel X710 onboard NIC

Everything rebooted and came up fine. None of my test systems are AMD based at the moment!

john.c

I don’t have AMD based hosts for XCP-ng. However may I suggest an additional validation test of this change, against Debian 13 when stable is released during or following tomorrow. I recon it should work - newer Linux Kernel version 6.12 series, though can’t be sure! Best check to avoid nasty surprises.

TeddyAstie

@john.c said in XCP-ng 8.3 updates announcements and testing:

I don’t have AMD based hosts for XCP-ng. However may I suggest an additional validation test of this change, against Debian 13 when stable is released during or following tomorrow. I recon it should work - newer Linux Kernel version 6.12 series, though can’t be sure! Best check to avoid nasty surprises.

The performance fix support is related to the kernel version. All kernel >= 5.19 work with it (or that have https://lore.kernel.org/all/20220530082634.6339-1-jgross@suse.com/), this includes Debian 13.

Andrew

@gduperrey Updated and running. Single hosts were fine. No AMD testing.

Upgrading a busy pool seems to have had some odd issues with VM migration, but all seems to be running fine now. I had upgraded the pool from 8.2.1 to 8.3 last month and everything has been fine. This time (after rebooting pool master) while trying to migrate guests so I could reboot hosts got a few XO errors like:

xo:api WARN admin | vm.migrate(...) [1s] =!> XapiError: INTERNAL_ERROR(Object with type VM and id bd38ee46-2701-3022-ec61-03bf3ffbdcc9/config does not exist in xenopsd)
xo:api WARN admin | vm.migrate(...) [2s] =!> XapiError: INTERNAL_ERROR(Object with type VM and id 235de1d7-832e-f1a7-fa1c-a45877aab8f6/config does not exist in xenopsd)

It was only a few on one host. I can NOT confirm this is related to the updates as I'm not having problems now. After manually rebooting the host and stuck guests, things were ok again.

olivierlambert

Updated and enabled (but on an Intel machine so far). I think I will enable it on our prod with the new config, this won't hurt (full EPYC)

bufanda

Installed on a 2 Node pool consisting of 2
HP EliteDesk 300 G3 Mini with

1x i7 6700T & 1x i5 6500T
32GB RAM each
NFS VM SR
iSCSI VM SR
various SMB ISO SR

VMs migrated during reboot withput issues, also no issues with migration after updates completed with all nodes rebooted. Alos no issues found with VMs. Primarily AlmaLinux 9 and FreeBSD 13.

gb.123

@gduperrey
@olivierlambert

First of all ...... a BIG THANK YOU for this patch !

Tested on Minisforum AMD 7945HX based pc; and I can confirm that XCP-ng boots with ACPI PSS & C Cores as mentioned in this post and it works with both options enabled.

So excited that I have tested this only and replied before testing other things..

UPDATE :
While updating this, I actually had to do 2 updates (last stable update patch of 7 files + this one)

After this installation, GPU (Nvidia) passthrough completely seems to be broken. Before the update(s) the host had to be turnoff completely, power cable had to be removed and then replugged to reset the graphics card (which used to work as I was able to run the card); but now attaching the graphics card to VM makes the VM hang on VM boot and at times, the host is also abruptly restarted (as if someone as pressed the HW reset button).

I am not sure whether the problem is in this update or the last stable one; but graphics card reset for Nvidia ( I think it has to do with ACPI reset ) still remains a problem.

Would be great if you guys can look into this.

olivierlambert

Updated on our prod cluster, works very well (full EPYC)

Andrew

@gduperrey I updated my little AMD Ryzen 5 5600U (Zen3) and it's running great!

As for the important VM to VM network performance, using Debian 13 and iperf3 single thread, before (update not enabled) is about 7.2-8Gb/sec. After the update (xen-platform-pci-bar-uc=false) I get about 10.1-13Gb/sec. So that's about a 40-60% improvement. This brings it in line with similar small Intel systems.

I did not see any change (or problem) setting it on my small test Intel system (getting about 10.1-10.8Gb/sec).

FYI: Remember, after the config change and xe-toolstack-restart, restart the VMs!

olivierlambert

Yeah I had to stop then start the VM to enjoy the new performance. On my end, iperf (not iperf3) bring even more perf on my setup, especially with multiple threads (-P4 and -P8 gave more than 100% boost)