To ensure a successful upgrade of the vCenter Server appliance, you must perform the following required tasks and pre-checks before beginning the upgrade process.

General Prerequisites

Target System Prerequisites

  • Verify that your system meets the minimum software and hardware requirements. See System Requirements for the New vCenter Server Appliance.
  • If you plan to deploy the new appliance on an ESXi host, verify that the target ESXi host is not in lockdown or maintenance mode.
  • If you plan to deploy the new appliance on an ESXi host managed by vCenter Server, review the Distributed Resource Scheduler (DRS) settings on the cluster. Ensure that the DRS settings for the cluster on which the target ESXi host resides are not configured for Full Automation. Set the Automation Level to Manual or Partially Automated. This Automation Level ensures that the target ESXi host does not reboot during the upgrade process.
  • If you plan to deploy the new appliance on a DRS cluster of the inventory of a vCenter Server instance, verify that the cluster contains at least one ESXi host that is not in lockdown or maintenance mode.
  • If you plan to upgrade a vCenter Server instance in an environment that has vSphere with Tanzu enabled, verify that you deploy the new appliance on a cluster where the Supervisor is not running. Ensure that the DRS settings for the cluster on which the target ESXi host resides are not configured for Full Automation.

Source System Prerequisites

  • If the source appliance is on a DRS cluster of the inventory of a vCenter Server instance and during upgrade:

    • If you plan to use the ESXi host where the appliance resides, review the Distributed Resource Scheduler (DRS) settings on the cluster. Ensure that the DRS settings of the cluster is set to manual or partially automated so that the VMs of the source system do not move during the upgrade.

    • If you plan to use the vCenter Server instance where the appliance resides, you need not modify the DRS settings of the cluster.

  • Verify that port 22 is open on the vCenter Server appliance that you want to upgrade. The upgrade process establishes an inbound SSH connection to download the exported data from the source vCenter Server appliance.
  • If you are upgrading a vCenter Server appliance that is configured with an external Update Manager, run the Migration Assistant on the source Update Manager computer.

    For a GUI upgrade, you must run Migration Assistant manually. See Download and Run VMware Migration Assistant on the Source Windows Machine.

    For a CLI upgrade, you can run Migration Assistant manually or automatically. To run Migration Assistant automatically, add the source.vum section section and run.migration.assistant subsection to your JSON template. See Upgrade Configuration Parameters for CLI Upgrade of vCenter Server Appliance.

  • Verify that port 443 is open on the source ESXi host on which the appliance that you want to upgrade resides. The upgrade process establishes an HTTPS connection to the source ESXi host to verify that the source appliance is ready for upgrade and to set up an SSH connection between the new and the existing appliance.
    Note: When upgrading, the temporary vCenter Server instance requires the same access rights as the permanent vCenter Server instance to port 443. Ensure that any firewalls in your environment allow both the temporary and permanent vCenter Server instances to access port 443.
  • Verify that you have sufficient free disk space on the appliance that you want to upgrade so that you can accommodate the data for the upgrade.
  • Create an image-based backup (snapshot) of the vCenter Server appliance you are upgrading as a precaution in case there is a failure during the upgrade process. If you are upgrading a vCenter Server appliance with an external Platform Services Controller, you must first converge the external Platform Services Controller to an embedded Platform Services Controller and then perform the upgrade. See Knowledge Base article KB 68137.
    Important: To take a pre-upgrade image-based backup in an Enhanced Linked Mode environment, power off all the vCenter Server and Platform Services Controller nodes in your environment, and back up each node. After you have taken backups of all the nodes, you can restart them and proceed with the upgrade procedure.

    If the upgrade fails, delete the newly deployed vCenter Server appliance, and restore the vCenter Server and Platform Services Controller nodes from their respective backups. You must restore all the nodes in the environment from their backups. Failing to do so will cause the replication partners to be out of synchronization with the restored node.

    To learn about image-based back, see "Image-Based Backup and Restore of a vCenter Server Environment" in vCenter Server Installation and Setup.

  • If you use an external database, determine the database size and the minimum storage size for the new appliance. See Determine the Oracle Database Size and the Storage Size for the New Appliance.
  • If your deployment uses an external database, you must back up the external vCenter Server appliance database.
  • If you plan to upgrade a vCenter Server instance in an environment that has vSphere with Tanzu enabled, ensure that the DRS settings of the cluster where the vCenter Server appliance resides is set to manual or partially automated so that the VMs of the source system do not move during the upgrade.

Network Prerequisites

  • Verify that the new appliance can connect to the source ESXi host and vCenter Server instance on which resides the appliance that you want to upgrade.
  • If you plan to assign a static IP address and an FQDN as a system name in the temporary network settings of the appliance, verify that you have configured the forward and reverse DNS records for the IP address.
  • If you plan to assign a DHCP IP address in the temporary network settings of the new vCenter Server appliance, verify that the ESXi host on which you want to deploy the new appliance is in the same subnet as the ESXi host on which the existing vCenter Server appliance runs.
  • If you plan to assign a DHCP IPv4 address in the temporary network settings of the new vCenter Server appliance, verify that the ESXi host on which you want to deploy the new appliance is connected to at least one network that is associated with a port group which accepts MAC address changes. Consider the default security policy of a distributed virtual switch, which is to reject MAC address changes. For information about how to configure the security policy for a switch or port group, see vSphere Networking.