Good morning, afternoon, evening or night to everybody.

The beta release of XCP-ng 8.0 is available right now .

What's new

• Based on Citrix Hypervisor 8.0 (see https://xen-orchestra.com/blog/xenserver-7-6/).
• New kernel (4.19), updated CentOS packages (7.2 => 7.5)
• Xen 4.11
• New hardware supported thanks to the new kernel. Some older hardware is not supported anymore. It's still expected work in most cases but security cannot be guaranteed for those especially against side-channel attacks on legacy Intel CPUs. See Citrix's Hardware Compatibility List. Note: in 7.6 we've started providing alternate drivers for some hardware. That's something we intend to keep doing, so that we can extend the compatibility list whenever possible. See https://github.com/xcp-ng/xcp/wiki/Kernel-modules-policy.
• ). Note: in 7.6 we've started providing alternate drivers
• Experimental UEFI support for guests (not tested yet: have fun and report!)
• An updated welcome HTML page with the ability to install Xen Orchestra Appliance directly from there (see below). Tell us how it works for you and what you think of it!
• A new implementation of the infamous emu-manager, rewritten in C. Test live migrations extensively!
• Mirrors: you can offer mirrors and yum now pulls from them: https://github.com/xcp-ng/xcp/wiki/Mirrors
• Already includes the latest patches for MDS attacks.
• The net-install installer now checks the signature of the downloaded RPMs against our GPG key, which is becoming more important now that we're delegating downloads to mirrors.
• Status of our experimental packages:
  • ext4 and xfs support for local SR are still considered experimental, although no one reported any issue about it. You still need to install an additional package for it to work: yum install sm-additional-drivers.
  • ZFS packages are now available in the main repositories, can be installed with a simple yum install zfs, and have been updated to version 0.8.1 (as of 2019-06-18) which removes the limitations we had with the previous version in XCP-ng 7.6.
  • No more modified qemu-dp for Ceph support, due to stalled issue in 7.6 (patches need to be updated). However the newer kernel brings better support for Ceph and there's some documentation in the wiki: https://github.com/xcp-ng/xcp/wiki/Ceph-on-XCP-ng-7.5-or-later.
  • Alternate kernel: none available yet for 8.0, but it's likely that we'll provide one later.
• New repository structure. updates_testing, extras and extras_testing disappear and there's now simply: base, updatesandtesting`. Extra packages are now in the same repos as the main packages, for simpler installation and upgrades.
• It's our first release with close to 100% of the packages rebuilt in our build infrastructure, which is Koji: https://koji.xcp-ng.org. Getting to this stage was a long path, so even if it changes nothing for users it's a big step for us. For the curious ones, more about the build process at https://github.com/xcp-ng/xcp/wiki/Development-process-tour.

Documentation

At this stage you should be aware that our main documentation is in our wiki and you should also know that you can all take part in completing it. Since the previous release, it has improved a lot but there's still a lot to improve.

How to upgrade

As usual, there should be two different upgrade methods: classical upgrade via installation ISO or upgrade using yum.

However, the yum-style update is not ready yet. Since this is a major release, Citrix does not support updating using an update ISO, and the consequence for us is that the RPMs have not been carefully crafted for clean update. So it's all on us, and we plan to have this ready for the RC (release candidate).

Before upgrading, remember that it is a pre-release, so the risks are higher than with a final release. But if you can take the risk, please do and tell us how it went and what method you used! However, we've been testing it internally with success and xcp-ng.org already runs on XCP-ng 8.0 (which includes this forum, the main repository and the mirror redirector) !

Although not updated yet, the Upgrade Howto remains mostly valid (except the part about yum-style upgrade, as I said above).

• Standard ISO: http://mirrors.xcp-ng.org/isos/8.0/xcp-ng-8.0.0-beta.iso
• Net-install ISO: http://mirrors.xcp-ng.org/isos/8.0/xcp-ng-8.0.0-netinstall-beta.iso
  • Do not use the pre-filled URL which still points at XCP-ng 7.6. Use this instead: http://mirrors.xcp-ng.org/netinstall/8.0
• SHA256SUMS: http://mirrors.xcp-ng.org/isos/8.0/SHA256SUMS
• Signatures of the sums: http://mirrors.xcp-ng.org/isos/8.0/SHA256SUMS.asc

It's a good habit to check your downloaded ISO against the SHA256 sum and for better security also check the signature of those sums. Although our mirror redirector does try to detect file changes on mirrors, it's shoud always be envisioned that a mirror (or in the worst case our source mirror) gets hacked and managed to provide both fake ISOs and SHA256 sums. But they can't fake the signature.

Stay up to date

Run yum update regularly. We'll fix bugs that are detected regularly until the release candidate. Subscribe to this thread (and make sure to activate mail notifications in the forum parameters if you need them): we'll announce every update to the beta here.

What to test

Everything!

Report or ask anything as replies to this thread.

A community effort to list things to be tested has been started at https://github.com/xcp-ng/xcp/wiki/Test-XCP

Hello to everyone.

The Release Candidate (RC) release of XCP-ng 8.1 is available right now .

This post is a mostly a copy-paste from the beta release announcement, with additions regarding the RC release.

Stability status

Good as far as we call tell from our tests and beta feedback. I would personally use it in production (actually we probably will very soon at Vates). The main unknown is how well the new coalesce algorithm will perform. Now is the time for as large testing as possible before the final release.

What changed

Here's what changes from XCP-ng 8.0. Changes since the 8.1 beta are in bold characters.

Non-exhaustive list:

• Based on Citrix Hypervisor 8.1 (https://docs.citrix.com/en-us/citrix-hypervisor/whats-new.html).
• Same base version of CentOS (7.5)
• Same base version of kernel (4.19, with more patches of course)
  • Latest kernel hotfix from CH 8.1 included in the RC release.
• Xen 4.13
• UEFI support for guests is not experimental anymore
• Support for Secure Boot is NOT INCLUDED because it relies on Proprietary packages. We're raising the issue with the Xen community to see how to provide a FOSS implementation.
• Citrix announces:
  • "Improved performance for VM imports and exports that use the XVA format" thanks to the use of a very efficient hash algorithm
  • "Storage performance improvements"
  • "New Windows I/O drivers with improved performance"
  • (From https://bugs.xenserver.org/browse/XSO-951) The next update (apparently not published yet as of 2020-01-27) of the Windows Drivers through Windows Update should at last be compatible with non-english locales!
• chrony replaces ntp
• Support for PV guests is now deprecated
  • templates for creating PV guests have been removed
  • existing guests will still run
  • it is advised to convert them to HVM guests
  • a compatibility layer should be provided in the future for PV guests that really can't be converted. But really anyone who can convert to HVM, should
  • due to how 32-bit PV guests work, keeping it functioning on newer hardware with newer features comes with an increasing performance cost, and the linux kernel is about to drop support for 32-bit PV guests
• Support for AMD EPYC 7xx2(P) added
• Dynamic Memory Control (DMC) is deprecated and will be removed in the future.
• VSS and quiesced snapshots support is removed, because it never worked correctly and caused more harm than good.
  • For backups, we are working on support for backups that include the guest RAM to replace the need for quiesced snapshots.
  • Note that Windows guest tools version 9 (the default for recent versions of Windows if you install through Windows Update) already removed VSS support, even for older versions of CH / XCP-ng
• For new local storage repositories using the EXT filesystem, it now defaults to ext4.
  • The transition from our experimental ext4 storage driver is not automatic.
  • Instructions for transitioning written in specific section below.
  • sm-additional-drivers package updated to refuse to create new experimental ext4 SRs since ext4 is already the default with the ext driver.
• Status of our specific packages:
  • Experimental support for XFS in local storage repository still available through the sm-additional-drivers package.
  • ZFS still available as an additional package and updated to 0.8.3.
  • Alternate kernel now available, version 4.19.102 (probable update to 4.19.108 before final release). Installing it now automatically adds a new boot entry in grub's configuration, to make testing easier. Default entry remains that of the main kernel.
  • netdata RPMs are now ready
    • @r1 contributed a fix to netdata project to bring support for Xen 4.13
    • @stormi made netdata cache be RAM-only to workaround an upstream bug that could make the disk cache grow forever
• Plans are laid out for simpler installation and maintenance of Windows guest tools. Unfortunately, we haven't found resources yet to implement them so the current state remains that of 8.0. If you're a developer on the Windows platforms, we're hiring! (full time or part time, contracts or hires) - Contact us.
• Installer improvements in 8.1 RC: see section below.
• New leaf coalesce logic of VDIs with dynamic limits: see section below.
• Fixed VM Autostart issues in 8.1 beta when updated from 8.0 through yum (upstream bug https://bugs.xenserver.org/browse/XSO-978)
• Fixed netxtreme drivers (bnx2x module) that crashed with some models
• Updated zstd to 1.4.4. Possibly even better perfs according to upstream. Still no import/export comparative benchmarks to 8.0. Does anyone volunteer?

Installer improvements in 8.1 RC

Our installer now offers two new installation options. In BIOS mode, access them with F2 when offered the choice. In UEFI mode, see the added boot menu entries.

• First new option: boot the installer with a 2G RAM limit instead of the 8G default. This is a workaround for installation issues on hardware with Ryzen CPUs. Though those are Desktop-class CPUs and not supported officially in the HCL, we tried to make it easier to workaround the infamous "installer crashes on Ryzen" issue.
• Second new option: boot the installer with our alternate kernel (kernel-alt). That kernel, built and maintained by @r1 for the team, is based on the main kernel, with all upstream kernel.org patches from the LTS 4.19 branch applied. It should be very stable by construction but it receives less testing. That option is there for cases when the main kernel and drivers have issues, so that you can quickly test if kernel.org patches have fixed it already. It will also install the alternate kernel in addition to the main kernel as a convenience. If kernel-alt fixes issues for you, the most important thing to do is to tell us so that we may fix the main kernel!

Announcement about our former experimental ext4 SR driver

It is now deprecated in 8.1. For a good reason: in XCP-ng 8.1 and above, following upstream changes, the ext driver now formats new SRs as EXT4. Existing SRs are untouched (so remain formatted to EXT3).

There is no easy way to convert an existing SR created with our driver, so those using it will need to move the VDIs out (to another SR or to export them), destroy the SR and create an EXT SR instead. Make sure to do this on XCP-ng 8.1.

The sm-additional-drivers package remains available in XCP-ng 8.1 in order to ease the transition. However I've broken the sr-create command on purpose. Any attempt to create a SR of type ext4 will result in an error with a message that explains that you need to use the ext type instead.

Our experimental driver will be completely removed in a later release, possibly XCP-ng 8.2. Unless someone convinces me to delay the removal for a good reason. I will accept reasons such as "I know I shouldn't have used the experimental driver in production, but I did and need more time to convert my SR while at the same time I really need feature xxx from XCP-ng 8.2", but I really would prefer to drop it in 8.2.

Feedback from people doing the transition is welcome to make sure we document the transition in the best way possible.

New leaf coalesce logic with dynamic limits

I have backported patches from sm's master branch, that implement a new, smarter, logic for leaf coalescing.

Those interested in the patches, see https://github.com/xcp-ng-rpms/sm/commit/ed1a55d727846cf5777c8258e6a8f3b068e8a35b (python code).

Feedback wanted.

Documentation

At this stage you should already be aware that our main documentation is in our wiki and you should also know that you can all take part in completing it. It's improving continuously and still has room for improvement.

How to upgrade from XCP-ng 8.1 beta

Just use yum update or Xen Orchestra as if you were installing updates to a stable release.

How to upgrade from previous releases

Since XCP-ng 8.1.0 is a minor release, both upgrade methods are supported:

• From the installation ISO
• From command line using yum (from XCP-ng 8.0 only!)

Refer to the upgrade howto: https://github.com/xcp-ng/xcp/wiki/Upgrade-Howto

Downloads:

• Standard ISO: http://mirrors.xcp-ng.org/isos/8.1/xcp-ng-8.1.0-RC1.iso
• Net-install ISO: http://mirrors.xcp-ng.org/isos/8.1/xcp-ng-8.1.0-RC1-netinstall.iso
• SHA256SUMS: http://mirrors.xcp-ng.org/isos/8.1/SHA256SUMS
• Signatures of the sums: http://mirrors.xcp-ng.org/isos/8.1/SHA256SUMS.asc

If your browser tells you that the page is redirected in a way that prevents from loading the page correctly, this is a known issue. Long story short, it's caused by a wrong security header sent by the forum software, which impacts all non HTTPS requests to the xcp-ng.org domain. Try in Private Navigation mode or use curl or wget.

It's a good habit to check your downloaded ISO against the SHA256 sum and for better security also check the signature of those sums. Although our mirror redirector does try to detect file changes on mirrors, it's should always be envisioned that a mirror (or in the worst case our source mirror) gets hacked and managed to provide both fake ISOs and SHA256 sums. But they can't fake the signature. See https://github.com/xcp-ng/xcp/wiki/How-to-check-the-authenticity-of-files-downloaded-from-XCP-mirrors.

Stay up to date

Run yum update regularly. We'll fix bugs that are detected regularly until the final release. Subscribe to this thread (and make sure to activate mail notifications in the forum parameters if you need them): we'll announce every important update to the RC here.

What to test

Everything and Anything!

Report or ask anything as replies to this thread.

A community effort to list things to be tested has been started at https://github.com/xcp-ng/xcp/wiki/Test-XCP

Feedback is welcome both about successes and failures.

Hello to everyone.

There's a very important way to prove to the world that your software is good: excellence in documentation. A project without good documentation is not appealing and looks un-professional.

I mentioned it here or there, but never made a proper announcement, so here it is: we are now using the wiki on our github project to store documentation:

https://github.com/xcp-ng/xcp/wiki

Now, as you can see, it's missing a lot of useful information. Every red link leads to a non-existent page that should exist, and I probably forgot to add many of them. Thankfully, our community comprises many experienced users of XS and XCP-ng, so we should be able to fill the gap.

I'm myself totally unable of writing documentation about storage or networking. My field of expertise is packaging, updates, releases, patching, writing some code. So I only write about what I know. But I'm sure you're not thinking that I will write the documentation alone.

So this is the official start of the "let's improve the documentation together" campaign. Any github user has write access to that wiki (it's versioned so we can revert changes from trolls if needed).

Don't ask for permission before adding or modifying something to the documentation. Just do it, and others will review it.

Even the structure of the home page can be modified. I made one to help us start and see where contributions are needed, but it's just a way to help us start.

Who's in? If you were looking for a way to get involved in XCP-ng but did not know how, here's your chance!

It's now live!

https://xcp-ng.org/blog/2022/11/18/xcp-ng-8-3-alpha/

Hello everyone.

I'm Samuel Verschelde. I started working full-time on XCP-ng on the 18th or June, so little more than one week ago. It's a pleasure to join your community and to devote my time to this free software project.

Obviously, my first mission targets the release of XCP-ng 7.5. So I figured I'd write a status update post to let you know what's been done, what is being done and what remains to be done. It's easy to get carried away by technical work and to forget to communicate, and I'll try not to fall in this trap. Since I'm still quite new to XCP-ng, please forgive me in advance any approximation or mistake in what I'll write. Just don't hesitate to point any mistake I might be doing, or any omission.

What needs to be done

So, basically the process of releasing the new version of XCP-ng, at the moment (this will evolve), is as follows:

• Get the installation and source ISOs from XenServer 7.5.
• Rebrand to XCP-ng and remove trademarked material (Citrix name, XenServer name, Citrix logo, splash screen...).
• Modify the licensing system to remove the restrictions for features that depend on free software.
• Remove proprietary software components from Citrix that we aren't allowed to redistribute.
• Fix a few known bugs
• Create an update repository for transitioning from 7.4
• Build the installation ISO
• Test (internally at first, but we'll quickly involve the community)
• Release
• (ideally, because we're a free software project after all) Provide source RPMs.

So were are we at this stage?

Rebrand to XCP-ng and remove trademarked material

Mostly done.

We do this for legal reasons, and Citrix obviously doesn't want its name (or XenServer) to be associated with XCP-ng.
Amusingly, though, they added their name in the description of several packages in 7.5. Some of these additions are clarifications, so that's good to help us detect proprietary software or trademarked material among the free software components.

But some other are suprising, such as what they did to the linux kernel package: they added a Citrix logo image in the package (which otherwise contains free software), and then changed the package license from GPLv2 to Portions GPL, Portions Non-Redistributable (See description). And description of the package now contains:

Citrix, the Citrix logo, Xen, XenServer, and certain other marks appearing
herein are proprietary trademarks of Citrix Systems, Inc., and are
registered in the U.S. and other countries. You may not redistribute this
package, nor display or otherwise use any Citrix trademarks or any marks
that incorporate Citrix trademarks without the express prior written
authorization of Citrix. Nothing herein shall restrict your rights, if
any, in the software contained within this package under an applicable
open source license.

Portions of this package are 2017 Citrix Systems, Inc. For other
copyright and licensing information see the relevant source RPM.

A lot of claims for an added logo.

Since the kernel contained by this package is free software, we made a new package without the added claims and without that added logo, so that we can redistribute it.

Modify the licensing system to remove the restrictions for features that depend on free software

We hoped we could simply reuse our package from 7.4.1 but it seems it's not sufficient. Investigations by @johnelse are in progress. Maybe they changed the protocol, maybe we just need a rebuild against latest xapi.

Remove proprietary software components from Citrix that we aren't allowed to redistribute

Some are easy to remove, such as the ParaVirtualization (PV) tools for Windows, which are proprietary. I've been told that Xen Orchestra has support for installing them easily, so we shouldn't miss them too much.

There's one that's giving @johnelse trouble, though: EMU Manager

This closed-source component is tightly coupled to other free software core components. Since I know little about it, I'll let John explain:

emu-manager is a layer between xenopsd (the host-level domain management daemon) and xenguest (which deals with the creation of xen domains) and vgpu (which does the graphics emulation for vGPU)
It is invoked when VMs are suspended, resumed or migrated

To put things in a few words: there's a close-source component that we can't remove without losing suspend, resume and migrate features. So we have to replace it with a free-software component of our own, and that's a hard work: the interfaces are public but not the internals. And we'll lose the vGPU migration ability in the process.

We expect to finish this in two weeks from now, but that may slip. If you think you can help, contact @johnelse or come discuss on the #xcp-ng-dev IRC channel on freenode (we both are on a European timezone).

Fix a few known bugs

• Broken link to XCP-ng center in the HTML welcome page: fixed for 7.5.
• Missing /etc/shadow and other files in install.img: will be fixed when building the new ISO images.
• Fix xcp-python-libs bug mentioned at https://xcp-ng.org/forum/topic/79/configure-dom0-memory-not-work
• Maybe more? I'm not sure this list is exhaustive.

Create an update repository for transitioning from 7.4

Nearly done.

Build the installation ISO, Test, Release

Depends on the above other tasks.

Community involvement

Now that I'm available almost all the time, it should become easier to include contributers from the community. We don't have the target infrastructure for that yet, but it's already possible to help at various stages. So don't hesitate to discuss it on this forum, to contact me ( stormi-xcp@ylix.fr ) or to come to chat on freenode's #xcp-ng-dev IRC channel.

And if you read all of this, thanks!

FYI, I have just published security updates today PLUS the fixed ixgbe driver as an official update to XCP-ng 8.1 and 8.2.

We made it. This is the end of this huge thread.

A big thank you to everyone involved in debugging the issue.

And this is not a :D.

Context: various recent devices on the consumer market require network drivers which are not present in XCP-ng 8.2.

Based on the work made with @Andrew for XCP-ng 8.3, I've finally found some time to backport the drivers to XCP-ng 8.2.

The following optional driver packages will soon be updated on the default repositories:

• igc-module (backported from kernel 5.10.150): adds support for Intel I225/I226.
• intel-e1000e-alt (updated to 3.8.7): adds support for Intel I219-V.
• r8125-module (updated to 9.010.01) for RealTek r8125. Quoting @Andrew:

  Note: This 8125 driver has SG/TSO, PTP, RSS enabled by default.
  Note: This 8125 driver has (optional) firmware loading enabled. Please manually download the rtl8125 firmware and install in XCP in /usr/lib/firmware/rtl_nic .
  Note: The 8125 Chipset/PCI-E card/driver has been known to cause system problems and crashes (not an XCP problem).

These are Additional packages, which means only best effort support is provided for them.

Update (2023-05-03): packages now moved to the xcp-ng-updates repository, which means they can be installed with a simple yum install name_of_package, without the need for extra parameters.

I'm publishing new updates to the base repository of XCP-ng 8.3:

• Security fixes for AMD
• Debian 12 VM template
• Removal of the old and unused experimental EXT4 SR driver. Don't jump: the main EXT SR driver still uses EXT4. I'm talking of the old experimental driver we added back then when the default EXT driver would use EXT3 only. This experimental driver has been deprecated since XCP-ng 8.1.
• smartmontools updated to version 7 which brings JSON output
• A fix for live migration support in IPv6-only pools

XCP-ng 8.3 beta 1 is released!

Announcement: https://xcp-ng.org/blog/2023/06/22/xcp-ng-8-3-beta-1/

This thread is the place where we can discuss this release and where all testers can provide feedback.

Update: AND now Beta 2 released too. We're keeping the same thread.

Hello here! I hope you are ready, because we'll have a train of update candidates for you to test shortly

Here's a work in progress version of the FAQ that will go with the release.

QCOW2 FAQ

What storage space available do I need to have on my SR to have large QCOW2 disks to support snapshots?

Depending on a thin or thick allocated SR type, the answer is the same as VHD.
A thin allocated is almost free, just a bit of data for the metadata of a few new VDI.

For thick allocated, you need the space for the base copy, the snapshot and the active disk.

Must I create new SRs to create large disks?

No. Most existing SR will support QCOW2. LinstorSR and SMBSR (for VDI) does not support QCOW2.

Can we have multiples different type of VDIs (VHD and QCOW2) on the same SR?

Yes, it’s supported, any existing SR (unless unsupported e.g. linstor) will be able to create QCOW2 beside VHD after installing the new sm package

What happen in Live migration scenarios?

preferred-image-formats on the PBD of the master of a SR will choose the destination format in case of a migration.

source	preferred-image-format VHD or no format specified	preferred-image-format qcow2
qcow2 >2 TiB	X	qcow2
qcow2 <2 TiB	vhd	qcow2
vhd	vhd	qcow2

Can we create QCOW2 VDI from XO?

XO hasn’t yet added the possibility to choose the image format at the VDI creation.
But if you try to create a VDI bigger than 2TiB on a SR without any preferred image formats configuration or if preferred image formats contains QCOW2, it will create a QCOW2.

Can we change the cluster size?

Yes, on File based SR, you can create a QCOW2 with a different cluster size with the command:

qemu-img create -f qcow2 -o cluster_size=2M $(uuidgen).qcow2 10G
xe sr-scan uuid=<SR UUID> # to introduce it in the XAPI

The qemu-img command will print the name, the VDI is <VDI UUI>.qcow2 from the output.

We have not exposed the cluster size in any API call, which would allow you to create these VDIs more easily.

Can you create a SR which only ever manages QCOW2 disks? How?

Yes, you can by setting the preferred-image-formats parameter to only qcow2.

Can you convert an existing SR so that it only manages QCOW2 disks? If so, and it had VHDs, what happens to them?

You can modify a SR to manage QCOW2 by modifying the preferred-image-formats parameter of the PBD’s device-config.

Modifying the PBD necessitates to delete it and recreate it with the new parameter. This implies stopping access to all VDIs of the SR on the master (you can for shared SR migrate all VMs with VDIs on other hosts in the pool and temporarily stop the PBD of the master to recreate it, the parameter only need to be set on the PBD of the master).

If the SR had VHDs, they will continue to exist and be usable but won’t be automatically transformed in QCOW2.

Can I resize my VDI above 2 TiB?

A disk in VHD format can’t be resized above 2 TiB, no automatic format change is implemented.
It is technically possible to resize above 2 TiB following a migration that would have transferred the VDI to QCOW2.

Is there any thing to do to enable the new feature?

Installing updated packages that supports QCOW2 is enough to enable the new feature (packages: xapi, sm, blktap). Creating a VDI bigger than 2 TiB in XO will create a QCOW2 VDI instead of failing.

Can I create QCOW2 disks lesser than 2 TiB?

Yes, but you need to create it manually while setting sm-config:image-format=qcow2 or configure preferred image formats on the SR.

Is QCOW2 format the default format now? Is it the best practice?

We kept VHD as the default format in order to limit the impact on production. In the future, QCOW2 will become the default image format for new disks, and VHD progressively deprecated.

What’s the maximum disk size?

The current limit is set to 16 TiB. It’s not a technical limit, it’s a limit that we corresponds to what we tested. We will raise it progressively in the future.

We’ll be able to go up to 64 TiB before meeting a new technical limit related to live migration support, that we will adress at this point.

The theoretical maximum is even higher. We’re not limited by the image format anymore.

Can I import without modification my KVM QCOW2 disk in XCP-ng?

No. You can import them, but they need to be configured to boot with the drivers like in this documentation: https://docs.xcp-ng.org/installation/migrate-to-xcp-ng/#-from-kvm-libvirt
You can just skip the conversion to VHD.

So it should work depending on different configuration.

(co-written with @dthenot)

QCOW2 RC2 release notes

Hello everyone,

We’re happy to publish the second and last release candidate for QCOW2 support in XCP-ng 8.3, before general availability.

It allows to use the QCOW2 open format (from Qemu) for virtual disks (VDIs) instead of the VHD format, and overcome the limitations imposed by the latter. The most important one being a size limit of 2 TiB per virtual disk.

Adding support for QCOW2 to XCP-ng 8.3 has been a 1.5 year journey, mobilizing many developers of the XCP-ng team.

There was a double challenge :

• Add the new feature, for those among you who really need large disks.
• Maintain the strong reliability of the current VHD support, that is what you are using now in production.

We managed to offer support for this new format without requiring to destroy and re-create your existing storage repositories. However, adding this QCOW2 support had a large impact on the codebase. More than you would usually want on a LTS product.

That’s why we invested a lot of energy, time, and resources on QA. So that we can offer this feature without affecting XCP-ng’s stability.

We need the final touch now, that is: feedback from the community.

The most important test is also the simplest: update your labs (and/or less important pools) from the testing repository, and verify that it all works as expected. VMs, snapshots, live migration, making backups, restoring backups… You don’t need to actually use the new QCOW2 format for your tests to be extremely useful.

Then, you can also start using the new disk format if you wish so (see below).
The new packages versions are:

• blktap-3.55.5-6.4.xcpng8.3
• sm-3.2.12-17.2.xcpng8.3
• xapi-26.1.3-1.6.xcpng8.3

For those of you who took part in the previous betas and RC

First, a big thank you! Then, important information about this RC2.

End of the dedicated repository

You can now remove the dedicated repository file, /etc/yum.repos.d/xcp-ng-qcow2.repo. Future updates will follow the normal pattern.

VHD by default

You will notice one major difference: the default for image format has gone back to being VHD, rather than QCOW2.
Your QCOW2 VDIs will still work after the update, but, by default, migrating a VDI to a SR will try to create a VHD instead of a QCOW2 (and will cause migration to fail if the VDI is bigger than 2TiB).

You can change this behaviour by defining QCOW2 as the preferred image format for the target SR. See below.

Image format management (VHD, QCOW2)

This update introduces the concept of image formats. The two possible image formats are now vhd (our historical format) and qcow2.

1. Each storage repository (except LINSTOR and SMB) supports both image formats.
2. SRs will create any new disk as VHD by default, in order to retain the same behaviour as before the update.
   Exception: Xen Orchestra will automatically try to create a QCOW2 disk if the virtual size is bigger than 2TiB.
3. During a storage migration from a SR to another SR, the destination format is chosen by the destination SR, following the same rules as for the creation of a new disk (this can be used to convert from one format to another).

If you want all new VDIs to be created as QCOW2 disks on a SR, you can set its preferred-image-formats on your SR.

Configuring a SR’s preferred-image-formats

New SRs

Configuring the preferred image format for new SRs can be done in Xen Orchestra’s SR creation form.

You can also still add the parameter at the SR creation on the command line with xe: device-config:preferred-image-formats=qcow2
Example:

xe sr-create name-label="test-lvmsr" type=lvm device-config:device=/dev/nvme1n1 device-config:preferred-image-formats=qcow2

Existing SRs

To tell an existing SR that it must prefer the qcow2 image format for new disks, it is necessary to unplug, destroy, recreate and re-plug its PBD with the added parameter in the device-config: https://docs.xcp-ng.org/storage/#-how-to-modify-an-existing-sr-connection
In order to unplug the PBD, any VMs with a VDI on the SR will have to be stopped, or the VDI moved temporarily to another SR.

This operation will not affect the contents of the SR. The PDB object represents the connection to the SR.

Why is it plural?

Don’t mind the s at the end of preferred-image-formats for now. At the moment, only the first element of the list is used in most cases.
One exception: if you define the preferred image formats as vhd, qcow2 and attempt to create a new disk with size > 2TiB, Xen Orchestra will automatically select QCOW2 as the format. This is the default for SRs without a configured preferred image format.

Creating a QCOW2 Virtual Disk (VDI) directly

Without changing the preferred image format of the whole SR, you can also directly create a QCOW2 VDI. This is not exposed in Xen Orchestra yet.

Use the xe vdi-create command with sm-config:image-format=qcow2.

Example:

xe vdi-create sr-uuid=<SR UUID> virtual-size=5TiB name-label="My QCOW2 VDI" sm-config:image-format=qcow2

What’s interesting to know

What is notable:

• The current maximum limit is 16 TiB per VDI. We could technically go beyond, but we’re only testing up to 16 TiB at the moment.
• We are using the default cluster size from Qemu, which is 64KiB. It is possible to create a VDI with bigger cluster size, see the FAQ for info.
• Our implementation of QCOW2 support also adds native support for drives with block sizes higher than 512B. This will progressively make the largeblock SR driver obsolete, as any SR type which supports the QCOW2 image format, if configured with qcow2 as its preferred-image-formats
• For users of the largeblock SR, QCOW2 is working on drives with blocksize >512B, the limitation for devices with blocksize of 4KiB is only for VHD. As such it is possible to use a normal SR instead of largeblock if you configure preferred-image-formats to be QCOW2.
• For backups jobs containing QCOW2 images, NBD need to be active on the backup job in XO.

What is not supported:

• QCOW2 image format for LINSTOR SRs (XOSTOR)
• QCOW2 image format for SMB SRs

What is coming soon:

• A way to select the destination format for a migration is being added in XAPI. Currently, the format is only decided by the preferred format of the destination SR
• We have ongoing work to improve performances of the storage stack in general (not just for QCOW2).

Known issues

• Snapshot of RAW VDIs (it would create a VHD or QCOW2 image with the parent being the RAW VDI)
• Migrating a > 2TiB VDI towards a SR whose preferred image format is not qcow2 (it will attempt to create a VDI, and fail)
• We have identified a problem with BIOS VMs when the boot disk is almost exactly 2TiB, 4TiB, 8TiB or 16TiB big. Having the disk being 1MiB bigger or smaller will allow the VM to boot. If you encounter this issue, resizing again with a bit more (minimum 1MiB) should make the disk boot again.

How to install

The update is provided as a regular update candidate in the testing repository. There are other update candidates being published at the same time. You can see what's in the update by looking at the announcement: https://xcp-ng.org/forum/topic/9964/xcp-ng-8-3-updates-announcements-and-testing/432

You can update from the testing repository:

yum clean metadata --enablerepo=xcp-ng-testing,xcp-ng-candidates
yum update --enablerepo=xcp-ng-testing,xcp-ng-candidates

A reboot is necessary after the update.

Time window for the tests

We’re aiming for a general release in about two weeks, maybe three. Given the tight timeline, your feedback will be especially valued!

@manilx Yes, as written

@bogikornel said:

@FritzGerald workaround

yum update --exclude=net-snmp*

This is dangerous.

Although disabling ssh-rsa is the right thing to do from a security perspective, we'll see what we can do to smoothen the transition.

Mentioning also @Team-Hypervisor-Kernel who now manages the drivers.

Maybe it's related to https://github.com/xcp-ng-rpms/microsemi-aacraid/issues/2#issuecomment-3837183087

It looks like the switch to the vendor driver instead of the kernel built-in for 8.3 (initiated by XenServer, and that we followed at the time as it was probably made in order to support newer cards) was not without drawbacks.

To elaborate: it was already in progress, but delayed due to 1. the fact that I underestimated the impact (I thought we'd overwrite the file only when we'd modify it, not every update the package) and 2. lots of other priorities keeping the team busy.

But it's clearly the reminder, and the help in better diagnosing it, that allowed to have it re-prioritized and (partly, we've mostly bought time to fix it properly, by simply avoiding to touch the file at all at the moment) fixed so fast.

@olivierlambert No it wasn't

The fix was already high in the priority list anyway, but I'll try to make sure we don't postpone it more. Had I realized sooner, I would have made it so we'd release it earlier.

According to the package definitions, we even overwrite it each time we update the xcp-ng-release-config package. I'm surprised that we haven't had more support requests.

I'll see if we can release a quick fix that just leaves the file alone until we apply the change that will move the remote configuration to its own file.

@MajorP93 Thanks. That clarifies what happened. I wrongly thought that it was managed in /etc/rsyslog.conf (which never gets overwritten), but it's in /etc/rsyslog.d/xenserver.conf, which can get overwritten if modified by an update.