Update your hosts

Updates can often be applied with minimal service interruption. We recommend that customers use XenCenter to apply all updates. If you are updating a Citrix Hypervisor pool, you can avoid VM downtime by using the Install Update wizard in XenCenter. The Install Update wizard applies updates, updating one host at a time, automatically migrating VMs away from each host as the hotfix or update is applied.

You can configure XenCenter to check periodically for available Citrix Hypervisor and XenCenter updates and new versions. Any Alerts are displayed in the Notifications pane.

Note:

Ensure that you use the latest version of XenCenter to apply updates to your Citrix Hypervisor hosts and pools. The latest version of XenCenter is provided on the Citrix download site.

Types of update

The following types of updates are available for Citrix Hypervisor:

• Releases, which are full releases of Citrix Hypervisor that can be applied as updates to the supported versions of Citrix Hypervisor.

• Hotfixes, which generally supply bug fixes to one or more specific issues. Hotfixes are provided for supported Citrix Hypervisor releases.

• Cumulative Updates, which contain previously released hotfixes and can contain support for new guests and hardware. Cumulative updates are applied to Citrix Hypervisor releases from the Long Term Service Release (LTSR) stream.

• Supplemental packs, which are provided by our partners and can also be applied as updates to Citrix Hypervisor.

• Driver disks, which are a type of supplemental pack that enables you to use the latest hardware.

Notes:

• If you use XenCenter to update your hosts, you must update your XenCenter installation to the latest version before beginning.
• Always update the pool master before updating any other hosts in a pool.

Releases

Citrix Hypervisor 8.2 Cumulative Update 1 is an update for Citrix Hypervisor 8.2. However, now that Citrix Hypervisor 8.2 is no longer supported, updating from Citrix Hypervisor 8.2 to Hypervisor 8.2 Cumulative Update 1 is no longer supported.

Hotfixes

We might release hotfixes for Citrix Hypervisor 8.2 Cumulative Update 1 that provide fixes for specific issues.

Hotfixes for Citrix Hypervisor 8.2 Cumulative Update 1 are made available from the Citrix Knowledge Center. We recommend that customers regularly check the Knowledge Center for new updates. Alternatively, you can subscribe to email alerts for updates to Citrix Hypervisor by registering for an account at http://www.citrix.com/support/.

Hotfixes on the latest release are available to all Citrix Hypervisor customers. However, hotfixes on previous releases that are still in support are only available for customers with an active Citrix Customer Success Services (CSS) account.

Hotfixes on the LTSR stream are available to customers with an active CSS account. For more information, See Licensing.

Cumulative Updates

Cumulative Updates are provided for LTSRs of Citrix Hypervisor. These updates provide fixes for issues, and may contain support for new guests and hardware.

Cumulative Updates are available to customers with an active CSS account.

Driver disks

You can install a driver disk using one of the following methods:

• By using XenCenter (recommended)
• During a clean Citrix Hypervisor installation
• By using the xe CLI

For information on how to install a driver disk by using XenCenter, see Install driver disks. For information on how to install a driver disk during a clean Citrix Hypervisor installation, see Install the Citrix Hypervisor server.

After installing the driver, restart your server for the new version of the driver to take effect. As with any software update, we advise you to back up your data before installing a driver disk.

Install a driver disk by using the xe CLI

Perform the following steps to install the driver disk remotely using the xe CLI:

1. Download the driver disk to a known location on a computer that has the remote xe CLI installed.

2. Extract the contents of the zip file.

   For the next step, ensure that you use the driver ISO and not the ISO that contains the source files.

3. Upload the driver disk:

   xe [connection_parameters] update-upload file-name=
   <!--NeedCopy-->
   

   The UUID of the driver disk is returned when the upload completes.

4. Apply the driver disk:

   xe [connection_parameters] update-apply uuid=
   <!--NeedCopy-->
   

5. To complete the installation, restart the host. The driver does not take effect until after the host is restarted.

Configure XenCenter to download updates

Downloading updates from https://support.citrix.com is restricted to customers with a Citrix account. Some updates are only available to customers who are part of Citrix Success Services. These restrictions are now enforced by XenCenter.

To receive updates through XenCenter, you must first install the latest version of XenCenter and obtain a client ID JSON file. For more information, see Authenticating your XenCenter to receive updates.

Prepare a pool for an update

Updates to Citrix Hypervisor can be delivered as a hotfix or a Cumulative Update or a Current Release. Pay careful attention to the release notes published with each update. Each update can have unique installation instructions, particularly regarding preparatory and post-update operations. The following sections offer general guidance and instructions for applying updates to your Citrix Hypervisor systems.

Before you apply an update to the Citrix Hypervisor pool, pay careful attention to the following:

• All hosts in the pool must be running Citrix Hypervisor 8.2 before you apply the hotfix.

• Back up your data before applying an update. For backup procedures, see Disaster recovery and backup.

• Before applying a Cumulative Update, check that the hardware your pool is installed on is compatible with the version of Citrix Hypervisor you are about to update to. For more information, see the Hardware Compatibility List (HCL).

• Before applying a Cumulative Update, check that the operating systems of your VMs are supported by the version of Citrix Hypervisor you are about to update to. If your VM operating system is not supported in the target version of Citrix Hypervisor, upgrade your VM operating system to a supported version. For more information, see Guest operating system support.

• Paravirtualized (PV) VMs are not supported in Citrix Hypervisor 8.2 Cumulative Update 1. 32-bit PV VMs are blocked from starting on Citrix Hypervisor 8.2 Cumulative Update 1 servers. Ensure that before updating you remove any PV VMs from your pool or upgrade your VMs to a supported version of their operating system. For more information, see Upgrade from PV to HVM guests.

  Earlier versions of the Citrix License Server virtual appliance run in PV mode. We recommend that you transition to using the Windows-based Citrix License Server as part of updating to Citrix Hypervisor 8.2 Cumulative Update 1.

• If you have Windows VMs running in your pool that will be migrated as part of the update, take the following steps for each VM:

  • Set the value of the following registry key to a REG_DWORD value of ‘3’: HKLM\System\CurrentControlSet\services\xenbus_monitor\Parameters\Autoreboot
  • Ensure that the latest version of the XenServer VM Tools for Windows is installed
  • Take a snapshot of the VM

• If you have Linux VMs running in your pool that will be migrated as part of your upgrade, ensure that the latest version of the Citrix VM Tools for Linux is installed.

• Update all servers in a pool within a short period: running a mixed-mode pool (a pool that includes updated and non-updated servers) is not a supported configuration. Schedule your updates to minimize the amount of time that a pool runs in a mixed state.

• Update all servers within a pool sequentially, always starting with the pool master. XenCenter’s Install Update wizard manages this process automatically.

• After applying an update to all hosts in a pool, update any required driver disks before restarting Citrix Hypervisor servers.

• After applying a Cumulative Update or Current Release to a host, apply any hotfixes released for that Cumulative Update or Current Release before migrating VMs onto the host.

• Legacy SSL mode is no longer supported. Disable this mode on all hosts in your pool before attempting to update to the latest version on Citrix Hypervisor. To disable legacy SSL mode, run the following command on your pool master before you begin the update: xe pool-disable-ssl-legacy uuid=<pool_uuid>

• The Container Management supplemental pack is no longer supported. After you update or upgrade to the latest version of Citrix Hypervisor, you can no longer use the features of this supplemental pack.

• The vSwitch Controller is no longer supported. Disconnect the vSwitch Controller from your pool before attempting to update to the latest version on Citrix Hypervisor. After the update, the following configuration changes take place:

  • Cross-server private networks revert to single-server private networks.
  • Any Quality of Service settings made through the DVSC console are no longer applied. Network rate limits are no longer enforced.
  • ACL rules are removed. All traffic from VMs is allowed.
  • Port mirroring (RSPAN) is disabled.

  After update or upgrade, if you find leftover state about the vSwitch Controller in your pool, clear the state with the following CLI command: xe pool-set-vswitch-controller address=

Before you begin updating

• Log into a user account with full access permissions (for example, as a Pool Administrator or using a local root account).

• Empty the CD/DVD drives of any VMs you plan to suspend. For details and instructions, see Before Upgrading a Single Citrix Hypervisor server.

• If applicable, disable high availability.

Apply updates to a pool

The update installation mechanism in XenCenter allows you to download and extract the selected update from the Support website. You can apply an update to multiple hosts and pools simultaneously using the Install Update wizard. During the process, the Install Update wizard completes the following steps for each server:

• Migrates VMs off the server
• Places the server in maintenance mode
• Applies the update to the server
• Reboots the host if necessary
• Migrates the VMs back to the updated host.

Any actions taken at the precheck stage to enable the updates to be applied, such as turning off HA, are reverted.

The Install Update wizard carries out a series of checks known as Prechecks before starting the update process. These checks ensure that the pool is in a valid configuration state. It then manages the update path and VM migration automatically.

Apply updates automatically

XenCenter allows you to apply automated updates that are required to bring your servers up-to-date. You can apply these updates to one or more pools. When you apply automated updates, XenCenter applies the minimum set of updates that are required to bring the selected pool or the standalone server up-to-date. XenCenter minimizes the number of reboots required to bring the pool or the standalone server pool up-to-date. Where possible, XenCenter limits it to a single reboot at the end. For more information, see Apply Automated Updates.

View available updates

The Updates section of the Notifications view lists the updates that are available for all connected servers and pools.

Notes:

• By default, XenCenter periodically checks for Citrix Hypervisor and XenCenter updates. Click Refresh to check manually for available updates.

• If you have disabled automatic check for updates, a message appears on the Updates tab. Click Check for Updates Now to check for updates manually.

You can select from the View list whether to view the list of updates By Update or By Server.

When you view the list of updates by update, XenCenter displays the list of updates. You can order these updates by server/pool or by date.

• Cumulative Updates and new releases are displayed at the top of this list. Not all new releases can be applied as an update.

• To export this information as a .csv file, click Export All. The .csv file lists the following information:
  • Update name
  • Description of the update
  • Servers that this update can be applied to
  • Timestamp of the update
  • A reference to the webpage that the update is downloaded from

• To apply an update to a server, from the Actions list for that update select Download and Install. This option extracts the update and opens the Install Update wizard on the Select Servers page with the relevant servers selected. For more information, see Apply an update to a pool.

• To open the release note of an update in your browser, click the Actions list and select Go to Web Page.

When you view the list of updates by server, XenCenter displays the list of servers connected to XenCenter. This list shows both the updates that you can apply to the servers and the updates that are already installed on the servers.

• To export this information as a .csv file, click Export All. The .csv file lists the following information:
  • Pool that the server belongs to
  • Server name
  • Status of the installed Citrix Hypervisor
  • Update status of the server
  • Required updates for this server
  • Installed updates for this server.
• To apply the updates, click Install Updates. This choice opens the Install Update wizard on the Select Update page. For more information, see Apply an update to a pool.

Apply an update to a pool

To apply an update to a pool by using XenCenter:

1. From the XenCenter menu, select Tools and then Install Update.

2. Read the information displayed on the Before You Start page and then click Next.

3. The Install Update wizard lists available updates on the Select Update page. Select the required update from the list and then click Next.

4. On the Select Servers page, select the pool and servers that you want to update.

   When applying a Cumulative Update or a Current Release, you can also select whether to apply the minimal set of hotfixes for the CU or CR.

   Click Next.

5. The Install Update wizard performs several prechecks to ensure that the pool is in a valid configuration state.

   The wizard also checks the following conditions:

   • Whether the hosts must be rebooted after the update is applied and displays the result.
   • Whether a live patch is available for the hotfix and whether the live patch can be applied to the hosts. For information about live patching, see Live Patching.

6. Follow the on-screen recommendations to resolve any update prechecks that have failed. If you want XenCenter to resolve all failed prechecks automatically, click Resolve All. When the prechecks have been resolved, click Next.

7. If you are installing a CU or a CR, XenCenter downloads the updates, uploads them to the default SR of the pool, and installs the updates. The Upload and Install page displays the progress.

   Notes:

   • If the default SR in a pool is not shared or does not have enough space, XenCenter tries to upload the update to another shared SR. If none of the shared SRs have sufficient space, the update is uploaded to local storage of the pool master.
   • If the update process cannot complete for any reason, XenCenter halts the process. This action allows you to fix the issue and resume the update process by clicking the Retry button.

   See Step 10. to complete the installation process.

8. If you are installing a hotfix, choose an Update Mode. Review the information displayed on the screen and select an appropriate mode. If the hotfix contains a live patch that can be successfully applied to the hosts, it displays No action required on the Tasks to be performed screen.

   Note:

   If you click Cancel at this stage, the Install Update wizard reverts the changes and removes the update file from the server.

9. Click Install update to proceed with the installation. The Install Update wizard shows the progress of the update, displaying the major operations that XenCenter performs while updating each server in the pool.

10. When the update is applied, click Finish to close Install Update wizard. If you chose to perform post-update tasks manually, do so now.

Update a pool of Citrix Hypervisor servers by using the xe CLI

Ensure that you update the pool master before you update any other pool member.

To update a pool of Citrix Hypervisor hosts by using the xe CLI:

1. Download the update file to a known location on the computer running the xe CLI. Note the path to the file.

2. Upload the update file to the pool you want to update by running the following:

   xe -s server -u username -pw password update-upload file-name=filename [sr-uuid=storage_repository_uuid]
   <!--NeedCopy-->
   

   Here, -s refers to the name of the pool master. Citrix Hypervisor assigns the update file a UUID, which this command prints. Note the UUID.

   Tip:

   After an update file has been uploaded to the Citrix Hypervisor server, you can use the update-list and update-param-list commands to view information about the file.

3. If Citrix Hypervisor detects any errors or preparatory steps that have not been taken, it alerts you. Be sure to follow any guidance before continuing with the update.

   If necessary, you can shut down or suspend any VMs on the hosts that you want to update by using the vm-shutdown or vm-suspend commands.

   To migrate specified VMs to specified hosts, use the vm-migrate command. By using the vm-migrate command, you have full control over the distribution of migrated VMs to other hosts in the pool.

   To live migrate all VMs to other hosts in the pool automatically, use the host-evacuate command. By using the host-evacuate command, you leave the distribution of migrated VMs to Citrix Hypervisor.

4. Update the pool, specifying the UUID of the update file, by running the following:

   xe update-pool-apply uuid=UUID_of_file
   <!--NeedCopy-->
   

   This command applies the update or hotfix to all hosts in the pool, starting with the pool master.

   Or, to update and restart hosts in a rolling manner, you can apply the update file to an individual host by running the following command:

   xe update-apply host=host uuid=UUID_of_file
   <!--NeedCopy-->
   

5. Verify that the update was applied by using the update-list command. If the update has been successful, the hosts field contains the host UUID.

6. Perform any post-update operations that are required, such as restarting the XAPI toolstack or rebooting the hosts. Perform these operations on the pool master first.

Ensure that you apply the update to all hosts in the pool. Running a mixed-mode pool (a pool that includes updated and non-updated servers) is not a supported configuration.

Update individual hosts by using the xe CLI

To update individual hosts by using the xe CLI:

1. Download the update file to a known location on the computer running the xe CLI. Note the path to the file.

2. Shut down or suspend any VMs on the hosts that you want to update by using the vm-shutdown or vm-suspend commands.

3. Upload the update file to the host you want to update by running the following:

   xe -s server -u username -pw password update-upload file-name=filename [sr-uuid=storage_repository_uuid]
   <!--NeedCopy-->
   

   Here, -s refers to the host name. Citrix Hypervisor assigns the update file a UUID, which this command prints. Note the UUID.

   Tip:

   After an update file has been uploaded to the Citrix Hypervisor server, you can use the update-list and update-param-list commands to view information about the update file.

4. If Citrix Hypervisor detects any errors or preparatory steps that have not been taken, it alerts you. Be sure to follow any guidance before continuing with the update.

5. Update the host, specifying the UUIDs of the host and the update file, by running the following:

   xe update-apply host-uuid=UUID_of_host uuid=UUID_of_file
   <!--NeedCopy-->
   

   If the host is a member of a pool, ensure that you update the pool master before you update any other pool member.

6. Verify that the update has been successfully applied by using the update-list command. If the update has been successful, the hosts field contains the host UUID.

7. Perform any post-update operations, as necessary (such as, restarting the XAPI toolstack, or rebooting the host).

Ensure that you apply the update to all hosts in the pool. Running a mixed-mode pool (a pool that includes updated and non-updated servers) is not a supported configuration.

Apply Automated Updates

Automated Updates mode applies any hotfixes and Cumulative Updates that are available for a host. This mode minimizes the number of reboots required to bring the pool or the standalone server pool up-to-date. Where possible, Automated Updates mode limits it to a single reboot at the end.

If a new Current Release version is available as an update, Automated Updates mode does not apply this update. Instead, you must select manually to update to the new Current Release.

XenCenter requires internet access to fetch the required updates.

To view the list of required updates, perform the following steps:

1. Select the host on the Resources pane in XenCenter.

2. Navigate to the General tab.

3. Expand the Updates section.

   You can see:

   • Applied – lists already-applied updates.

   • Required Updates – lists the set of updates required to bring the server up-to-date.

     Note:

     If there are no updates required, the Required Updates section is not displayed.

   • Installed supplemental packs – lists supplemental packs that are installed on the server (if any).

     Note:

     If you select a pool instead of a server, the Updates section lists updates that are already applied as Fully Applied.

If you want to choose and install a particular update, see Apply an update to a pool.

Note:

Automated Updates were previously restricted to Citrix Hypervisor Premium Edition customers or Citrix Virtual Apps and Desktops customers. However, in pools with hotfix XS82ECU1053 applied, this feature is available to all users.

Apply Automated Updates by using the Install Update wizard

The following section provides step-by-step instructions on how to apply the set of required updates automatically to bring your pool or standalone host up-to-date.

1. From the XenCenter menu, select Tools and then select Install Update.

2. Read the information displayed on the Before You Start page and then click Next.

3. On the Select Update page, select the mechanism to use to install the updates. You can see the following options:

   • Automated Updates – (default) this option is visible only if XenCenter is connected to at least one licensed pool or a licensed standalone server. Select this option to download and install all the current updates automatically to bring the pool or a standalone server up-to-date.

   • Download update from Citrix – the Install Update wizard lists available updates from the Support site. To apply the updates, see Apply an update to a pool.

   • Select update or Supplemental pack from disk – to install an update you have already downloaded, see Apply an update to a pool. To install supplemental pack updates, see the Installing Supplemental Packs article in XenCenter documentation.

4. To continue with the automatic application of hotfixes, select Automated Updates and then click Next.

5. Select one or more pools or standalone servers that you want to update and click Next. Any server or pool that cannot be updated appears unavailable.

6. The Install Update wizard performs several update prechecks, to ensure that the pool is in a valid configuration state.

   Follow the on-screen recommendations to resolve any update prechecks that have failed. If you want XenCenter to resolve all failed prechecks automatically, click Resolve All. When the prechecks have been resolved, click Next.

7. The Install Update wizard automatically downloads and installs the recommended updates. The wizard also shows the overall progress of the update, displaying the major operations that XenCenter performs while updating each server in the pool.

   Notes:

   • The updates are uploaded to the default SR of the pool. If the default SR is not shared or does not have enough space, XenCenter tries to upload the update to another shared SR with sufficient space. If none of the shared SRs have sufficient space, the update is uploaded to local storage on each host.

   • The update process cannot complete for any reason, XenCenter halts the process. This allows you to fix the issue and resume the update process by clicking the Retry button.

8. When all the updates have been applied, click Finish to close Install Update wizard.

Live patching in Citrix Hypervisor

The live patching feature applies to hotfixes only. Current Releases and Cumulative Updates cannot be applied as live patches.

Citrix Hypervisor customers who deploy Citrix Hypervisor servers can often be required to reboot their hosts after applying hotfixes. This rebooting results in unwanted downtime for the hosts while customers have to wait until the system is restarted. This unwanted downtime can impact business. Live patching enables customers to install some Linux kernel and Xen hypervisor hotfixes without having to reboot the hosts. Such hotfixes include both a live patch, which is applied to the memory of the host, and a hotfix that updates the files on disk. Using live patching can reduce maintenance costs and downtime.

When applying an update by using XenCenter, the Install Update wizard checks whether the hosts must be rebooted after the update is applied. XenCenter displays the result on the Prechecks page. This check enables customers to know the post-update tasks well in advance and schedule the application of hotfixes accordingly.

Note:

Citrix Hypervisor Live Patching is available for Citrix Hypervisor Premium Edition customers, or those customers who have access to Citrix Hypervisor through their Citrix Virtual Apps and Desktops entitlement or Citrix DaaS entitlement. To learn more about Citrix Hypervisor editions, and to find out how to upgrade, visit the Citrix website. For detailed information about Licensing, see Licensing.

Live patching scenarios

Hotfixes can be live patched across pools, hosts, or on a standalone server. Some require a reboot, some require the XAPI toolstack to be restarted, and some hotfixes do not have any post-update tasks. The following scenarios describe the behavior when a Live Patch is and is not available for an update.

• Updates with a live patch — Some hotfixes that update the Linux kernel and the Xen hypervisor usually do not require a reboot after applying the hotfix. However, in some rare cases, when the live patch cannot be applied, a reboot might be required.

• Updates without a live patch — No change in the behavior here. It works as usual.

  Note:

  If a host does not require a reboot, or if the hotfix contains live patches, XenCenter displays No action required on the Update Mode page.

Apply Automated Updates and live patching

Automated Updates mode in XenCenter enables you to download and apply the minimum set of hotfixes required to bring your pool or standalone host up-to-date automatically. Automated Updates mode does apply any Cumulative Updates that are available for a host. However, if a new Current Release version is available as an update, Automated Updates mode does not apply this update. You must manually select to update to the new Current Release.

You can benefit from the live patching feature when you apply hotfixes using the Automated Updates mode in XenCenter. You can avoid rebooting hosts if live patches are available and are successfully applied to the hosts that are updated using Automated Updates mode. For more information about the Automated Updates, see Apply Automated Updates.

Enable live patching by using XenCenter and the xe CLI

Live patching feature is enabled by default. Customers can enable or disable live patching using XenCenter or xe CLI command.

Using XenCenter

1. Select the pool or the standalone host on the Resource pane.

2. From the Pool menu (Server in case on standalone hosts) menu, select Properties and then click Live Patching.

3. On the Live Patching page:

   • Select Use live Patching when possible to enable live patching.

   • Select Don’t use Live Patching to disable live patching.

Using the xe CLI

• To enable live patching, run the following command:

   xe pool-param-set live-patching-disabled=false uuid="pool_uuid"
   <!--NeedCopy-->
  

• To disable live patching, run the following command:

   xe pool-param-set live-patching-disabled=true uuid="pool_uuid"
   <!--NeedCopy-->