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Jump To: Support > KB > Citrix > XenServer > Hotfixes

Citrix Hypervisor (XenServer) Hotfixes, suggested installation order and post-install actions

See page last modified date at bottom

Jump to: 8.2 LTSR and current release, 8.1, 7.1 LTSR

Each fix listed shows the immediate impact of applying the update:

  • no action required after installation - will have no effect on running machines
  • toolstack restart - Running machines will not be affected, but you will be temporarily disconnected in XenCenter (which will reconnect automatically after 120 seconds)
  • restart or migrate VMs - the hosts do not need rebooting, but for the hotfix to apply to the VMs, they will either need to be rebooted or live-migrated to another host which also has the hotfix on
  • reboot - the physical server will need rebooting, so VMs will need to be moved onto another server (or shutdown). If using XenCenter, it'll move the VMs around for you automatically to keep them running throughout. However, to speed things up you can move them all off the pool master yourself and update/reboot that completely (as it may require multiple reboots) before moving VMs back to it and upgrading the other servers
  • reboot or live patch - as above, but if you have XenServer Enterprise rights, the patch will be done live without requiring a reboot.
  • upgrade VM tools - The XenServer guest tools should be upgraded as soon as convenient, but machines will continue to work without. Do NOT upgrade tools in VMs that are provisioned

N.B. XenServer fixes for 7.1 and later are provided as .iso files rather than .xsupdate. They are applied in the same way except that you cannot double-click on the fix file to automatically open it in XenCenter; choose Install update... from the Tools menu.

N.B. (2) XenServer 7.1 and later supports live patching if you have XenServer Enterprise licences or XenServer for XenDesktop rights. This applies the patch without requiring a reboot. Some patches can only be applied without a reboot if a specific earlier patch is already installed.

N.B. (3) Hypervisor security patches after October 2017 (xen kernel 4.7.2-2.6 or later, e.g. XS72E008) will stop NetBSD VMs from booting. To remedy this, you must run the following on each host and then reboot for it to take effect:
/opt/xensource/libexec/xen-cmdline --set-xen pv-linear-pt=true

This setting will be removed on a version upgrade, so it must be re-applied when upgrading to Hypervisor 8.0, for example.

You can determine your xen kernel version using xl info:
# xl info | grep xen_version
xen_version            : 4.7.2-2.7

N.B. (4) XenServer tools older than 6.5 or the legacy tools included with XenServer 7 will not work on Citrix Hypervisor 8.0; the VM will BSOD. Please ensure you upgrade to the latest tools (if on a supported OS) or maintain a legacy 7.6 or 7.1 LTSR pool for your legacy VMs.

Citrix's list of recommended XenServer/Hypervisor hotfixes

XenCenter (all versions of XenServer)

Use latest version of XenCenter to manage all XenServer pool regardless of version

Windows VM Management Agent and I/O drivers

Details here:

Citrix Hypervisor 8.2 (LTSR and Current Release)

N.B. If using the free edition it is crucial that you read the list of features moved to a paid version before upgrading

XenServer 7.1 CU2 - Long Term Support Release

XenServer 7.1 is a Long Term Support Release (LTSR) offering support for 10 years, but this requires maintaining Customer Success Services (CSS, previously known as Software Maintenance). Without CSS, there are no updates further updates for 7.1 since 2017. If you do not have CSS, you should use the Current Release (7.6 at the time of writing). To switch to the LTSR branch, install XenServer 7.1 Cumulative Update 1 (CU1), then XenServer 7.1 Cumulative Update 2 (CU2). You may not install CU2 directly on 7.1. You may not downgrade from a Current Release (e.g. 7.6) to 7.1 CU2.

If you upgrade a host with legacy disk partition from XenServer 6.x to XenServer 7.1 CU1, and then attempt to apply XenServer 7.1 CU2 as an update, you may receive an insufficient space error. To avoid this happening, apply XS71ECU1033 on XS 7.1 CU1 before attempting to update to CU2.

XenServer 7.1 and earlier

We no longer maintain a list of hotfixes for 8.1 CR and earlier as we recommend all customers upgrade to 7.1 LTSR (if on 7.1 or earlier) or 8.2 (if on 7.2 or later).

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Page last modified on November 03, 2021, at 09:44 AM by sborrill