Product Documentation

Upgrading Managed Servers

Dec 10, 2014

You can use the Rolling Pool Upgrade wizard to upgrade XenServer hosts - hosts in a pool or standalone hosts to a newer version.

The wizard guides you through the upgrade procedure and organizes the upgrade path automatically. For pools, each of the hosts in the pool is upgraded in turn, starting with the pool master. Before starting an upgrade, the wizard conducts a series of prechecks to ensure that certain pool-wide features, such as HA and WLB, are temporarily disabled and that each host in the pool is prepared for upgrade (for example, that the CD/DVD drive of each host is empty). Only one host is offline at a time, and any running VMs are automatically migrated off each host before the upgrade is installed on that host.

The wizard can operate in manual or automatic mode:

  • In manual mode, you must manually run the XenServer installer on each XenServer host in turn and follow the on-screen instructions on the serial console of the host. Once the upgrade begins, XenCenter prompts you to insert the XenServer installation media or specify a PXE boot server for each host that you upgrade.
  • In automatic mode, the wizard uses network installation files located on an HTTP, NFS or FTP server to upgrade each host in turn, without requiring you to insert install media, manually reboot, or step through the installer on each host.

You can also use the Rolling Pool Upgrade wizard to upgrade standalone hosts, that is, hosts which are not in a pool.

Important: Before you upgrade

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

  • VMs can only be migrated from a XenServer host running an older version of XenServer to one running the same version or higher (for example, from version 6.2 to version 6.2 or from version 6.2 to version 6.5). You cannot migrate VMs from an upgraded host to one running an older version of XenServer (for example, from version 6.5 to version 6.2). Be sure to allow for space on your XenServer hosts accordingly.
  • Citrix strongly advises against running a mixed-mode pool (one with multiple versions of XenServer coexisting) for longer than necessary, as the pool operates in a degraded state during upgrade.
  • Key control operations are not available during upgrade and should not be attempted. Though VMs continue to function as normal, VM actions other than migrate may 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 will always upgrade the master host first. Do not place the master into maintenance mode using XenCenter before performing the upgrade as this will cause a new master to be designated.
  • Take a backup of the state of your existing pool using the pool-dumpdatabase xe CLI command (see the XenServer Administrator's Guide). This allows you to revert a partially complete rolling upgrade back to its original state without losing any VM data. Because it is not possible to migrate a VM from an upgraded XenServer host to a XenServer host running an older version of XenServer, it may be necessary to shut down VMs if you need to revert the rolling upgrade for any reason.
  • Ensure that your hosts are not over-provisioned - that 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 may choose to perform them before you begin the upgrade:
    • Empty the CD/DVD drives of the VMs in the pool(s). For details and instructions, see the XenServer Installation Guide.
    • Disable HA.
    • Disable WLB

To upgrade XenServer hosts 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 click Next to continue.
  3. Select the pool(s) and/or individual hosts that you wish to upgrade and then click Next.
  4. Choose Automatic Mode or Manual Mode, depending on whether you are planning an automated upgrade from network installation files located on an HTTP, NFS or FTP server, or a manual upgrade from either a CD/DVD or a server via PXE boot.
    Note: If you choose Manual Mode, you must run the XenServer installer on each XenServer host in turn and follow the on-screen instructions on the serial console of the host. Once the upgrade begins, XenCenter prompts you to insert the XenServer installation media or specify a PXE boot server for each host that you upgrade.

    Once you have selected your Upgrade Mode, click Run Prechecks.

  5. Follow the recommendations to resolve any upgrade prechecks that have failed. If you would like XenCenter to automatically resolve all failed prechecks, click Resolve All. Once all prechecks have been resolved, click Next to continue.
  6. Prepare the XenServer installation media:
    • If you chose Automatic Mode, enter the installation media details. Choose HTTP, NFS or FTP and then specify the path, username and password, as appropriate.
    • If you chose Manual Mode, note the upgrade plan and instructions.
    Click Start Upgrade to begin the upgrade.
  7. Once the upgrade begins, the wizard guides you through any actions you need to take to upgrade each host. Follow the instructions until you have upgraded all hosts in the pool(s).
  8. Once the upgrade completes, the wizard prints a summary. Click Finish to close the wizard.