Known issues

This article contains advisories and minor issues in the Citrix Hypervisor 8.2 release and any workarounds that you can apply.

General

• The backup and restore capability in xsconsole is temporarily not available. We are actively investigating a replacement solution. (CP-48776)

• If you host the Citrix License Server virtual appliance version 11.14 or earlier on your Citrix Hypervisor server, you see a warning when upgrading or updating to Citrix Hypervisor 8.2 Cumulative Update 1. The warning states that this virtual appliance is a PV VM that is no longer supported. We recommend that you transition to using the Windows-based Citrix License Server before upgrading or updating.

  The latest version of Citrix License Server is available from the Citrix Licensing download page.

• A pool’s CPU feature set can change while a VM is running. (For example, when a new host is added to an existing pool, or when the VM is migrated to a host in another pool.) When a pool’s CPU feature set changes, the VM continues to use the feature set which was applied when it was started. To update the VM to use the pool’s new feature set, you must power off and then start the VM. Rebooting the VM, for example, by clicking ‘Reboot’ in XenCenter, does not update the VM’s feature set. (CA-188042)

• The increase in the amount memory allocated to dom0 in Citrix Hypervisor 8.0 can mean there is slightly less memory available for running VMs. On some hardware, you cannot run the same number of VMs with Citrix Hypervisor 8.2 as you can on the same hardware with XenServer 7.6 and earlier. (CP-29627)

• When attempting to use the serial console to connect to a Citrix Hypervisor server, the serial console might refuse to accept keyboard input. If you wait until after the console refreshes twice, the console then accepts keyboard input. (CA-311613)

• When read caching is enabled, it is slower to read from the parent snapshot than from the leaf. (CP-32853)

• After upgrading to Citrix Hypervisor 8.2, when there is a lot of VM activity on a server in a pool that uses NFS storage, connections through ENIC to external storage can become temporarily blocked (5–35 minutes). VMs on that server can freeze and their consoles can become unresponsive. Attempts to ping in or out of the affected server subnet fail during these times. To fix this issue, install version 4.0.0.8-802.24 or later of the enic driver. For more information, see Driver Disk for Cisco enic 4.0.0.11 - For Citrix Hypervisor 8.x CR. (XSI-916)

• When attempting to log in to the dom0 console with an incorrect password, you receive the following error message: When trying to update a password, this return status indicates that the value provided as the current password is not correct. This error message is expected even though it relates to a password change, not a login. Try to log in with the correct password.

• If an Active Directory user inherits the pool admin role from an AD group that has spaces in its name, the user cannot log in to Citrix Hypervisor 8.2 CU1 through SSH.

  To work around this issue, you can do one of the following:

  • Rename this group in AD to remove the spaces from its name.
  • Create a new group in AD with the pool admin role and without spaces in its name. Add the user to this new group.

  In XenCenter, ensure that your new or renamed group is listed in the Users tab, either by adding or by removing and re-adding the group. Ensure that the user is associated with the new or renamed group. (CA-363207)

• In clustered pools, a network outage might cause the following issues: inability to reconnect to the GFS2 storage after a host reboot, inability to add or remove hosts in a pool, difficulties in managing the pool. If you experience any of these problems in your clustered pool, contact Citrix Support for advice about recovering your environment. (XSI-1386)

• If you apply hotfix XS82ECU1074 to a pool with more than 32 hosts, the hosts might disconnect intermittently due to tighter resource limits introduced by the hotfix. Future updates are planned to resolve this issue.

  For pools larger than 32 hosts, either avoid installing this hotfix or apply the following workaround before installation:

  1. Add the following entries to the /etc/xapi.conf file on each host in the pool:

     conn_limit_unix = 800
     conn_limit_tcp = 800
     <!--NeedCopy-->
     

  2. Restart the toolstack.

Graphics

• When you start in parallel many VMs with AMD MxGPU devices attached, some VMs might fail with a VIDEO_TDR_FAILURE. This behavior might be due to a hardware limitation. (CA-305555)

• When NVIDIA T4 added in pass-through mode to a VM on some specific server hardware, that VM might not power on. (CA-360450)

• You cannot install the NVIDIA Virtual GPU Manager supplemental pack as part of a fresh installation of your Citrix Hypervisor host. After you have installed your hosts, you can install NVIDIA Virtual GPU Manager by using the xe CLI or XenCenter. For more information, see Install the NVIDIA vGPU Manager for XenServer.

• On hardware with NVIDIA A16/A2 graphics cards, VMs with vGPUs can sometimes fail to migrate with the internal error “Gpumon_interface.Gpumon_error([S(Internal_error);S((Failure “No vGPU available”))])”. To recover the VM from this state, you must shut it down and start it again. (CA-374118)

• [Fixed in XS82ECU1031] When running a large number of virtual GPU or GPU pass-through enabled VMs, rebooting some VMs on the host might cause a performance glitch in the other VMs.

Guests

• Citrix Hypervisor no longer supports VMs that run in PV mode. In previous releases, after upgrading your Citrix Hypervisor server to the latest version, these unsupported VMs might still run. However, in Citrix Hypervisor 8.2 CU1, 32-bit PV mode VMs no longer start-up. Ensure that you remove any PV VMs from your pool or convert these VMs to HVM mode before upgrading to your pool to Citrix Hypervisor 8.2 CU1. For more information, see Upgrade from PV to HVM guests. (CP-38086)

• If you attempt to revert a VM to a scheduled VSS snapshot that was created with Citrix Hypervisor 8.0 or earlier, the VM does not boot. The boot fails with the following error: This operation cannot be performed because the specified virtual disk could not be found. This failure is because the VSS snapshot capability has been removed from Citrix Hypervisor 8.1 and later. (CA-329469)

Windows guests

• For domain-joined Windows 10 VMs (1903 and later) with FireEye Agent installed, repeated successful RDP connections can cause the VM to freeze with 100% CPU usage in ntoskrnl.exe. Perform a hard reboot on the VM to recover from this state. (CA-323760)

• The guest UEFI boot capability provided in Citrix Hypervisor 8.0 was an experimental feature. Citrix Hypervisor 8.2 does not support migrating UEFI boot VMs created in Citrix Hypervisor 8.0 to Citrix Hypervisor 8.2. Shut down UEFI boot VMs before upgrading to Citrix Hypervisor 8.2 from Citrix Hypervisor 8.0. (CA-330871)

• When UEFI-boot VMs start, they show a TianoCore logo. (CP-30146)

• On Windows VMs, when updating the xenbus driver to version 9.1.0.4, ensure that you complete both of the requested VM restarts. If both restarts are not completed, the VM might revert to emulated network adapters and use different settings, such as DHCP or different static IP addressing.

  To complete the second restart, you might be required to use a local account to log into the Windows VM. When you log in, you are prompted to restart.

  If you are unable to log in to the Windows VM after the first restart, you can use XenCenter to restart the VM and complete the xenbus driver installation. (CP-34181)

• When you create a UEFI VM, the Windows installation requires a key press to start. If you do not press a key during the required period, the VM console switches to the UEFI shell.

  To work around this issue, you can restart the installation process in one of the following ways:

  • In the UEFI console, type the following commands.

     EFI:
     EFI\BOOT\BOOTX64
    

  • Reboot the VM

  When the installation process restarts, watch the VM console for the installation prompt. When the prompt appears, press any key. (CA-333694)

• On a Windows VM, sometimes the IP address of an SR-IOV VIF is not visible in XenCenter. To fix the issue, restart the management agent from within the VMs Service Manager. (CA-340227)

• On a Windows VM with more than 8 vCPUs, Receive Side Scaling might not work because the xenvif driver fails to set up the indirection table. (CA-355277)

• When attempting to update a Windows 10 VM from 1909 to 20H2 or later, the update might fail with a blue screen showing the error: INACCESSIBLE BOOT DEVICE.

  To make it less likely that this failure occurs, you can take the following steps before attempting to update:

  1. Update the XenServer VM Tools for Windows on your VM to the latest version.
  2. Snapshot the VM.
  3. In the VM registry, delete the following values from the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\XENFILT\Parameters key: ActiveDeviceID, ActiveInstanceID, and ActiveLocationInformation

  This issue is still under investigation. (XSI-1075)

• When creating a Windows VM from a template that is set to not automatically update its drivers, the created VM is incorrectly set to update its drivers. To work around this issue, run the following command: xe pool-param-set policy-no-vendor-device=true uuid=<pool-uuid>. This command ensures that future VMs created from the template are correctly set to not automatically update drivers. VMs that were previously generated from the template are not changed. (CA-371529)

For details on the latest XenServer VM Tools for Windows release, see What’s new.

Linux guests

• You cannot use the Dynamic Memory Control (DMC) feature on Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Rocky Linux 8, Rocky Linux 9, or CentOS Stream 9 VMs as these operating systems do not support memory ballooning with the Xen hypervisor. (CA-378797) (CP-45141)

• On some Linux VMs, especially busy systems with outstanding disk I/O, attempts to suspend or live migrate the VM might fail. To work around this issue, try increasing the value of /sys/power/pm_freeze_timeout, for example, to 300000. If this work around is not successful, you can upgrade the Linux kernel of the VM to the latest version. (CP-41455)

• The Citrix VM Tools for Linux can provide an incorrect value for the free memory of the VM that is higher than the correct value. (CA-352996)

• If you install Debian 10 (Buster) (deprecated) by using PXE network boot, do not add console=tty0 to the boot parameters. This parameter can cause issues with the installation process. Use only console=hvc0 in the boot parameters. (CA-329015)

• After a CentOS 8 VM with only one CPU is migrated to a new Citrix Hypervisor server, the first time a CPU-bound command runs on the VM, it times out. To work around this issue, you can assign more than one CPU to the VM and restart it. (XSI-864)

• If you attempt to shut down a CentOS Stream 9 VM by using XenCenter or the xe CLI, the shutdown process pauses and times out after 1200s. This behaviour is caused by a kernel issue in kernel-5.14.0-362.el9.

  The following workarounds are available:

  • To work around a single instance of the issue, you can shut down the VM from inside the guest operating system.

  • To prevent the issue from occuring for your VM, downgrade your VM to use kernel-5.14.0-354.el9 by running the following commands in the VM:

     # yum install kernel-5.14.0-354.el9
     # grubby --set-default /boot/vmlinuz-5.14.0-354.el9.x86_64
    

• When installing Debian 11 32-bit on a VM using a QEMU emulated network device, the installation might fail. This issue is caused by the Xen PV drivers being missing from the installer kernel.

• Due to a known issue with Mesa drivers on Ubuntu 24.04, after installing an Ubuntu 24.04 (desktop) VM on an AMD platform host with the Wayland protocol enabled by default, you might experience repeated re-login prompts.

  We recommend to work around this issue by disabling Wayland or upgrading your Mesa drivers:

  • Disable Wayland

    Open a command prompt and run the following command:

     sudo nano /etc/gdm3/custom.conf
     <!--NeedCopy-->
    

    Set the following value to disable Wayland:

     WaylandEnable=false
     <!--NeedCopy-->
    

    Restart the VM to complete the process.

  • Update your Mesa drivers

    Run the following commands:

     sudo add-apt-repository ppa:kisak/kisak-mesa
     sudo apt update
     sudo apt upgrade
     <!--NeedCopy-->
    

    Restart the VM to complete the process.

Installation

• If you are using a legacy disk layout, the control domain has less space available to it than the current layout (4 GB vs 18 GB).

  In this case, when attempting to apply the Citrix Hypervisor 8.2 or Citrix Hypervisor 8.2 Cumulative Update 1 update to an earlier, you might receive the error message “the server does not have enough space”. This error happens because installation of the Citrix Hypervisor update requires sufficient free space to avoid filling the disk, which is not possible with the legacy layout.

  If you receive this error, you cannot update to Citrix Hypervisor 8.2 or Citrix Hypervisor 8.2 Cumulative Update 1. Do a fresh installation instead. (CA-268846)

• If any vSwitch Controller state remains in your pool after an update or upgrade, clear the state with the following CLI commands:

   xe pool-set-vswitch-controller address=
   xe pool-param-set uuid=<uuid> vswitch-controller=
  

  (CA-339411)

• Occasionally, booting a Citrix Hypervisor server from FCoE SAN using software FCoE stack can cause the host to stop responding. This issue is caused by a temporary link disruption in the host initialization phase. If the host fails to respond for a long time, you can restart the host to work around this issue.

• When upgrading to or installing Citrix Hypervisor 8.2 from an ISO located on an IIS server, the install or upgrade can fail and leave your servers unable to restart. The remote console shows the GRUB error: “File ‘/boot/grub/i3860pc/normal.mod’ not found. Entering rescue mode”. This issue is caused by the IIS configuration causing package files to be missing. To work around this issue, ensure that double escaping is allowed on IIS before extracting the installation ISO on it. (XSI-1063)

• [Fixed in XenCenter 8.2.6] If you have the Container Supplemental Pack installed on your XenServer 7.1 CU2 host and attempt to upgrade to Citrix Hypervisor 8.2 CU1 by using XenCenter, you are prevented from upgrading because the supplemental pack is no longer supported. For more information, see Deprecation.

  To work around the issue, use the xe CLI to complete the upgrade. This upgrade removes the Container Management Supplemental Pack. For more information, see Upgrade Citrix Hypervisor servers by using the xe CLI. (XSI-1250)

• [Fixed in the reissued Base Installation ISO - Feb 24, 2022] If your server has a NIC that requires the ice driver, this NIC is not available as part of the Citrix Hypervisor 8.2 CU1 installation process, as such you cannot configure it as the management interface or use it to retrieve installation files from a network server. Instead, use a different NIC during the installation process. (CA-363735)

• [Fixed in the reissued Base Installation ISO - Jun 5, 2022] If you attempt to install Intel® Xeon® 84xx/64xx/54xx/44xx/34xx (Sapphire Rapids) hardware with four or more sockets by using an installation ISO released before Jun 1, 2023, the installation fails. To successfully install on this hardware, use a version of the base installation ISO released after Jun 1, 2023.

Internationalization

• Non-ASCII characters, for example, characters with accents, cannot be used in the host console. (CA-40845)

• In a Windows VM with XenServer VM Tools for Windows installed, copy and paste of double-byte characters can fail if using the default desktop console in XenCenter. The pasted characters appear as question marks (?).

  To work around this issue, you can use the remote desktop console instead. (CA-281807)

Storage

• If you use GFS2 SRs and have two servers in your clustered pool, your cluster can lose quorum and fence during an upgrade. To avoid this situation, either add a server to or remove a server from your cluster. Ensure that you have either one or three servers in your pool during the upgrade process. (CA-313222)

• If you are using a GFS2 SR, ensure that you enable storage multipathing for maximum resiliency. If storage multipathing is not enabled, file system block writes might not fully complete in a timely manner. (CA-312678)

• Citrix Hypervisor doesn’t support MCS full clone VMs with GFS2 SRs. (XSI-832)

• If a Citrix Virtual Apps and Desktops or Citrix DaaS deployment with its VMs hosted on Citrix Hypervisor 8.2 uses multiple GFS2 SRs in a single MCS catalog, VMs in the catalog cannot access the VDIs during deployment. The error “VDI is currently in use” is reported. (XSI-802)

• If you are using a GFS2 SR and your cluster network is on a non-management VLAN, you cannot add or remove hosts to your clustered pool. (XSI-1604)

• If you use HPE 3PAR hardware for your storage repository and, with a previous release of XenServer, you use ALUA1 for your host persona, when you upgrade to Citrix Hypervisor 8.2 multipathing no longer works. To work around this issue, migrate your host persona to ALUA2. For more information, see https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c02663749&docLocale=en_US.

• After removing an HBA LUN from a SAN, you might see log messages and I/O failures when querying Logical Volume information. To work around this issue, reboot the Citrix Hypervisor server. (XSI-984)

• You cannot set or change the name of the tmpfs SR used by the PVS Accelerator Supplemental Pack. When the type is tmpfs, the command xe sr-create disregards the value set for name-label and instead uses a fixed value. If you attempt to run the command xe sr-param-set to change the name of the tmpfs SR, you receive the error SCRIPT_MISSING.

• You cannot run more than 200 PVS-Accelerator-enabled VMs on a Citrix Hypervisor server. (CA-365079)

• If you install hotfix XS82ECU1065, you cannot attach or reattach a read-only NFS SR.

• Sometimes, failures when leaf coalescing can lead to the allocated space being reported as higher than the expected value. This issue is caused by temporary snapshots being left behind by the failed leaf coalesce. To work around this issue, either shut down the VM or reduce its I/O load. The storage garbage collector can then succeed in coalescing the leaf. (XSI-1517)

Third-party

• A limitation in recent SSH clients means that SSH does not work for usernames that contain any of the following characters: {}[]|&. Ensure that your usernames and Active Directory server names do not contain any of these characters.

Workload Balancing

• During the Workload Balancing maintenance window, Workload Balancing is unable to provide placement recommendations. When this situation occurs, you see the error: “4010 Pool discovery has not been completed. Using original algorithm.” The Workload Balancing maintenance window is less than 20 minutes long and by default is scheduled at midnight. (CA-359926)

• In XenCenter, the date range showed on the Workload Balancing Pool Audit Report is incorrect. (CA-357115)

• For a Workload Balancing virtual appliance version 8.2.2 and later that doesn’t use LVM, you cannot extend the available disk space. (CA-358817)

XenCenter

• Changing the font size or dpi on the computer on which XenCenter is running can result in the user interface appearing incorrectly. The default font size is 96 dpi; Windows 8 and Windows 10 refer to this font size as 100%. (CA-45514) (CAR-1940)

• On Windows 10 (1903 and later) VMs, there can be a delay of a few minutes after installing the XenServer VM Tools before the Switch to Remote Desktop option is available in XenCenter. You can restart the toolstack to make this option appear immediately. (CA-322672)

• It is not advisable to update the same pool from concurrent instances of XenCenter because this might disrupt the update process.

  If more than one instance of XenCenter is attempting to install multiple hotfixes on a pool, a server might fail to install a hotfix with the error: “The update has already been applied to this server. The server will be skipped.” This error causes the whole update process to stop. (CA-359814)

  To workaround this issue:

  1. Ensure that no other XenCenter instance is in the process of updating the pool
  2. Refresh the update list in the Notifications > Updates panel
  3. Start the update from the beginning

• In XenCenter 8.2.3, importing an OVF or OVA file can be significantly slower than in earlier versions of XenCenter. (CP-38523)

• In XenCenter, when you attempt to import an OVF package or a disk image from a folder containing a hash character (#) in its name, the import fails with a null reference exception. (CA-368918)

• XenCenter shows a message marking Dynamic Memory Control (DMC) as deprecated. This deprecation is no longer the case. DMC is supported in future releases.

• In pools with hotfix XS82ECU1029 applied that have GFS2 SRs, using XenCenter to generate a server status report (SSR) can fail. To work around this issue, generate your SSRs by running the following command in the host console: xenserver-status-report. (CA-375900)

• If a hotfix requires another hotfix to already be installed as a prerequisite, XenCenter does not display the name of the prerequisite hotfix. You can find the prerequisite information in the article on https://support.citrix.com for the hotfix you are trying to install. (CA-383054)