Upgrading Managed Servers

You can use the Rolling Pool Upgrade wizard to upgrade Citrix Hypervisor - standalone servers or a pool of servers to a newer version.

Note:

Rolling Pool Upgrade is available for licensed Citrix Hypervisor customers, or customers who have access to Citrix Hypervisor through their Citrix Virtual Apps and Desktops entitlement. For more information, see About Citrix Hypervisor Licensing.

The Rolling Pool Upgrade wizard guides you through the upgrade procedure and organizes the upgrade path automatically. The Rolling Pool Upgrade wizard allows you to upgrade multiple servers and pools simultaneously. Each of the servers in the pool is upgraded in turn, starting with the pool master. Before starting an upgrade, the wizard conducts prechecks to ensure that certain pool-wide features, such as high availability and WLB, are temporarily disabled. THe wizard also checks that each host in the pool is prepared for upgrade. Only one server is offline at a time, and any running VMs are automatically migrated off each server before the upgrade is installed on that server.

The wizard can operate in manual or automatic mode:

  • In manual mode, you must manually run Citrix Hypervisor installer on each server in turn and follow the on-screen instructions on the serial console of the server. When the upgrade begins, XenCenter prompts you to insert Citrix Hypervisor installation media or specify a PXE boot server for each server that you upgrade.
  • In automatic mode, the wizard uses network installation files on an HTTP, NFS, or FTP server to upgrade each server in turn. THis mode does not require you to insert install media, manually reboot, or step through the installer on each server. If you perform a rolling pool upgrade in this manner, unpack the Citrix Hypervisor installation media onto your HTTP, NFS, or FTP server before starting the upgrade.

You can also use the Rolling Pool Upgrade wizard to upgrade standalone servers, that is, servers which do not belong to any resource pool.

Important: Before you upgrade

Upgrading a pool of servers requires careful planning. As you plan your upgrade, it is important to be aware of the following:

  • Download and install the latest version of XenCenter. For example, when you are upgrading your hosts to Citrix Hypervisor 8.1, you must use XenCenter issued with Citrix Hypervisor 8.1. Using earlier versions of XenCenter to upgrade to a newer version of Citrix Hypervisor is not supported.
  • VMs can only be migrated from a server that runs an older version of Citrix Hypervisor to one that runs the same version or higher. You cannot migrate VMs from an upgraded server to one running an older version of Citrix Hypervisor. Ensure to allow for space on your servers accordingly.
  • Citrix strongly advises against running a mixed-mode pool (one with multiple versions of Citrix Hypervisor coexisting) for longer than necessary. In this case, the pool operates in a degraded state during upgrade.
  • Do not attempt to perform any key control operations during upgrade. Though VMs continue to function as normal, VM actions other than migrate might not be available (for example, shut down, copy, and export). In particular, it is not safe to perform storage-related operations such as adding, removing, or resizing virtual disks.
  • The wizard upgrades the pool master first. Do not place the pool master into maintenance mode using XenCenter before performing the upgrade as this action causes a new master to be designated.
  • Take a backup of the state of your existing pool using the pool-dump-database xe CLI command. For more information, see Command line interface. Backups allow you to revert a partially complete rolling upgrade back to its original state without losing any VM data. As it is not possible to migrate a VM from an upgraded server to a server running an older version, you might have to shut down VMs to revert the rolling upgrade for any reason.
  • Ensure that your servers are not over-provisioned - that is, they have sufficient memory to carry out the upgrade. It is best to suspend any VMs that are not critical during the upgrade process.
  • While the Rolling Pool Upgrade wizard checks that the following actions have been taken, you might choose to perform them before you begin the upgrade:

To upgrade Citrix Hypervisor using the Rolling Pool Upgrade wizard

  1. Open the Rolling Pool Upgrade wizard: on the Tools menu, select Rolling Pool Upgrade.
  2. Read the Before You Start information, and then select Next to continue.
  3. Select the pool or standalone servers that you would like to upgrade and then select Next.
  4. Choose the Upgrade Mode.

    • You can select Automatic Mode for an automated upgrade from network installation files on an HTTP, NFS, or FTP server. If you choose the Automatic Mode, specify the location of the network installation file, user name, and password before continuing to the next step.
    • You can select Manual Mode for a manual upgrade from either a CD/DVD or a server using PXE boot. If you choose the Manual Mode, run the Citrix Hypervisor installer on each server in turn and follow the on-screen instructions on the serial console of the server. When the upgrade begins, XenCenter prompts you to insert Citrix Hypervisor installation media or specify a PXE boot server for each server that you upgrade.
  5. On the Upgrade Options page, choose whether you want XenCenter to automatically download and install the minimal set of updates after upgrading the servers to a newer version. The apply updates option is selected by default. However, you must have internet connection to download and install the updates.

    In addition, to allow XenCenter to install a previously downloaded update or a supplemental pack after upgrading the servers, select Install an update or supplemental pack from disk. Select Browse to choose the file. Selecting a file incompatible with the upgraded version of Citrix Hypervisor can cause the installation to fail.

  6. After choosing the Upgrade Options, select Run Prechecks.

  7. Follow the on-screen recommendations to resolve any upgrade prechecks that have failed. To allow XenCenter to automatically resolve all failed prechecks, select Resolve All. When the prechecks have been resolved, select Start Upgrade to begin the upgrade.

When the upgrade begins, the wizard guides you through any actions you need to take to upgrade each server. Follow the instructions until you have upgraded and updated all servers in the pool.

Note:

If the upgrade process fails for any reason, the Rolling Pool Upgrade wizard halts the process. This halt allows you to fix the issue and resume the upgrade process by clicking the Retry button.

The Rolling Pool Upgrade wizard prints a summary when the upgrade is complete. Select Finish to close the wizard.