Updating Managed Servers

XenCenter issues notifications about available XenServer updates in the Updates tab on the Notifications view. Updates to XenServer can be delivered as a Hotfix or a Service Pack. Hotfixes generally supply bug fixes to one or more specific issues; whereas Service Packs contain accumulated bug fixes, and occasionally, feature improvements and enhancements. This topic contains information about applying XenServer updates to your managed servers. You must pay careful attention to the release note that is published with each update. Each update may have unique installation instructions, particularly with regard to preparatory and post-update operations.

In addition to XenServer updates, the Updates tab also notifies users about the availability of new versions of XenServer and new versions of XenCenter. For information about upgrading XenServer, see Upgrading Managed Servers. To update your XenCenter to a newer version, see Updating XenCenter. For information about installing supplemental packs, see Installing Supplemental Packs.

XenCenter also enables you to dismiss updates listed on the Updates tab. Dismissing an update hides the update entry from the list. Select any unwanted updates from the list and click Dismiss and then Dismiss Selected. To dismiss all the updates, select Dismiss All. If you would like to see updates which were previously dismissed, click Restore Dismissed Updates.

Before you Update

Before you apply an update to your servers, you should pay careful attention to the following:

  1. Back up your data before applying an update, just as you would with any other maintenance operations. For backup procedures, see the XenServer 7.1 Administrator’s Guide.
  2. We recommend that you reboot all your servers before installing an update and then verify their configuration, for example, to check that the VMs start and that storage is accessible. This is because some configuration changes will only take effect when a server is rebooted, so the reboot may uncover configuration problems that could cause the update to fail.
  3. When you are upgrading a pool of servers to a newer version, you must upgrade each server in a pool starting with the pool master and ensure that the pool is up and running before applying any updates.
  4. 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. This should be scheduled to minimize the amount of time that a pool runs in a mixed state.
  5. Update all servers within a pool sequentially, always starting with the pool master.
  6. After applying an update to all servers in a pool, you should update any required driver disks before rebooting the servers.

Updating a Pool Automatically

XenCenter allows you to apply automated updates that are needed to bring your servers up-to-date. You can apply these updates to one or more pools. When you choose to 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 up-to-date, and where possible, limits it to a single reboot at the end. For more information, see Applying Automated Updates.

Applying an Update to your Managed Servers

The update installation mechanism in XenCenter allows you to download and extract the selected update from the Citrix Support website, and enables you to apply an update to multiple servers and pools simultaneously using the Install Update wizard. During the process, the Install Update wizard automatically migrates VMs off each server, places the server in Maintenance mode, applies the update, reboots the server if required, and then, migrate the VMs back to the updated server. Any actions that were taken at the pre-check stage to enable the updates to be applied, such as turning off HA, will be reverted.

The following section provides step-by-step instructions on extracting and applying an update using the Install Update wizard. If you are planning to apply an update that you have already downloaded from the Citrix Support website, see the section Installing previously downloaded updates.

  1. From the XenCenter navigation pane, click Notifications and then Updates. This provides a list of available updates.


    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. Select the pool and servers that you would like to update and click Next.
    5. Proceed to step 4 to continue with the update installation process.


    • By default, XenCenter periodically checks for XenServer and XenCenter updates. Click Refresh to manually check for available updates.
    • If the Updates tab cannot find any updates because you have disabled automatic check for updates, a message appears on the Updates tab. Click Check for Updates Now to manually check for updates.
  2. From the Updates list, select the required update and then click Download and Install from the Actions drop-down list. This extracts the update and opens the Install Update wizard on the Select Servers page with the relevant servers selected. If you would like to make any changes to the pool or the servers being updated, clear the check boxes. Any servers or pools that cannot be updated will be greyed out.

    Important: Citrix strongly recommends that customers read the release notes published with each update. To open the release note in your browser, click the Actions drop-down list and then select Go to Web Page.

  3. Review the server selection and click Next to continue. This downloads the update and uploads it to the default SR of the pool.
  4. The Upload page displays the status of the upload.

    Note: 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 with sufficient space. If none of the shared SRs have sufficient space, the update will be uploaded to local storage on each server.

  5. The Install Update wizard performs a number of update prechecks, including the space available on the servers, to verify that the update can be applied on the selected servers and displays the result. The wizard also checks whether the servers need to be rebooted after the update is applied and displays the result. In addition, the Install Update wizard checks whether a live patch is available for the update and whether the live patch can be successfully applied to the servers. For information about Live Patching, see Live Patching in XenServer.

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

  6. Choose an Update Mode. Review the information displayed on the screen and select an update mode. If the update contains a live patch that can be successfully applied to the servers, it displays No action required on the Update Mode page.

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

  7. 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.
  8. When the update has been applied, click Finish to close the Install Update wizard.
  9. If you chose to carry out the post-update tasks, do so now.

Installing previously downloaded updates

XenCenter enables you to install updates that you have already downloaded. Update files are delivered as zip files on the Citrix Support website.

Note: Updates to XenServer are published as .zip files. Download the zip file to a known location on your computer and make sure to extract the .iso file before installing the update.

  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. On the Select Update page, click Browse to locate the update file (.iso) and then click Open. Click Next to continue.
  4. Select the pool and servers that you would like to update. Any servers or pools that cannot be updated will be greyed out. Click Next to continue.
  5. Follow the instructions from step 3 to 9 in the section Applying an Update to your Managed Servers above to complete the update installation process.