Migrating Windows vCenter Server to VCSA 6.0

VMware vSphere 6.0 reached end of general support 12 March 2020, with vSphere 6.5 scheduled for 15 October 2022, both referenced in the VMware Lifecycle Matrix. See also How to Install vSphere 7.0. Upgrade to vSphere 7 can be achieved directly from vSphere 6.5.0 and above, whereas vSphere 6.0 requires an intermediate upgrade to 6.5 or 6.7 first. For more information see the VMware Upgrade Matrix. Finally, the Windows vCenter Server and external PSC deployment models are now depreciated and not available with vSphere 7.0.

VMware vCenter Server pools ESXi host resources to provide a rich feature set delivering high availability and fault tolerance to virtual machines. The vCenter Server is a centralised management application and can be deployed as a virtual appliance or Windows machine. This post gives a walk through on migrating from a Windows based vCenter Server (VCS) 5.5 to the Photon OS based vCenter Server Appliance (VCSA) 6.0.

About VCSA

The VCSA is a pre-configured virtual appliance running SUSE Linux Enterprise Server 11 Update 3 for VMware (x64), PostgreSQL, vCenter Server 6.0 and associated components. The embedded PostgreSQL database supports up to 1000 hosts and 10,000 virtual machines. The VCSA has now reached feature parity with its Windows counterpart, can be quickly provisioned and patched, and has no license requirements for operating system or database. There are a number of excellent VCSA additional features with the release of vSphere 6.5 and a migration tool for VCSA v5.5 to v6.5 will be released at a later date.

Migrating to VCSA involves the deployment of a new appliance and migration of all configuration (including distributed switches) and historical data using the upgrade installer. The VCSA uses a temporary IP address during migration before switching to the IP and host name of the VCS, the Windows box is then powered off. Last year there was a fling for migrating to VCSA which had limited capability and support. If you have used or read about the fling then re-review any limitations as a lot of this has been lifted now that VMware have released the migration tool as an official product.


Software Considerations

  • The Windows VCS must be running v5.5 (any build / patch) to migrate to VCSA. If the VCS is v5.0 or 5.1 then upgrade to 5.5 first and then migrate. Both physical and virtual vCenter Server installations are compatible.
  • Any database, internal or external, supported by VCS 5.5 can be migrated to the embedded PostgreSQL database within the target VCSA. All ESXi hosts connected must be running version 5.x.
  • The Windows server is powered off once the VCSA is brought online, this means any other components, VMware or third party, need to be migrated off the Windows server in advance or they will no longer work (don’t forget to move and update any scripts that may live on the Windows server).
  • This brings us on to Update Manager; if you use Update Manager it still requires a standalone Windows server. This is a big reason for many organisations to stay with a Windows vCenter however this is resolved in vSphere 6.5 where the VCSA includes an embedded Update Manager instance.
  • You must check compatibility of any third party products and plugins that might be used for backups, anti-virus, monitoring, etc. as these may also need upgrading for use with vSphere 6.0.
  • For other VMware products check the Product Interoperability Matrix.

Architectural Considerations

  • The implementation of vSphere 6 introduces a Platform Services Controller (PSC) which contains infrastructure services such as Single Sign On, Certificate Authority, licensing, etc. The PSC is deployed internally with vCenter Server or as an external component. You can read more about the PSC in this kb.
  • The migration tool supports different deployment topologies but does not, and can not, make changes to the topology and SSO domain configuration.
  • If SSO was installed on the same machine as vCenter Server then services are migrated to vCenter Server Appliance 6.0 Update 2 with embedded Platform Services Controller.
  • If SSO was installed on a different machine from vCenter Server then the Windows VCS server will be migrated to the vCenter Server Appliance 6.0 U2 with external Platform Services Contoller, and the Windows SSO server will be migrated to the Platform Services Controller 6.0 U2 Appliance.

Other Considerations

  • Variables such as FQDN resolution, database permissions and access to the licensing portal should all be in place since we are upgrading an existing vCenter solution.
  • Make sure any server running a vCenter component is synchronized with an NTP server. The installation can fail or the vCenter Server Appliance vpxd service may not be able to start if the clocks are unsynchronized.
  • If there are any firewalls between vSphere components then review this KB, e.g. data migration from the VCS to the VCSA uses SSH so port 22 must be open.
  • You will need the SSO administrator login details and if the Windows VCS service runs as a service account then the account must have replace a process level token permission.
  • Local Windows users that have vSphere permissions are not migrated since they are specific to the Windows server, all SSO users and permissions are migrated.
  • Downtime varies depending on the amount of data you are migrating, but can be calculated using this KB.
  • The upgrade can be easily rolled back by following this KB.
  • Ensure you have a good backup of the vCenter Server and the database.

Resources – vCenter Server 6.0 Update 2 Migration Release Notes, Migrating vCenter Server 5.5 to vCenter Server Appliance 6.0 U2m FAQ, a full list of pre-requisites including the minimum hardware and storage requirements can be studied at the vSphere 6 Documentation Centre.


Download VMware vCenter Server 6.0 U2M from VMware downloads. Note that the M denotes migration and this installer is specific to the migration from VCS to VCSA.


Before we begin if your existing Windows vCenter is virtual it may be beneficial to rename the inventory name in vSphere to include -old or equivalent. While the hostname and IP are migrated the vSphere inventory name cannot be a duplicate. The old server is powered down but not deleted so that we have a back out.

Mount the ISO and copy the migration-assistant folder to the Windows vCenter Server (and SSO server if separate). If SSO is running on a different Windows server then you must run the Migration Assistant on the SSO server first and migrate following the instructions below, then complete the same process on the Windows vCenter Server.

Start the VMware Migration Assistant and enter the SSO Administrator credentials to start running pre-checks.


If all checks complete successfully the Migration Assistant will finish at ‘waiting for migration to start’.


On a different machine from your Windows vCenter and SSO server(s) open the vcsa-setup.html file located on the root of the ISO, we only have one installation option; click Migrate.


Click Ok to the message about vCenter versions.


Accept the license terms and click Next.


Enter the details of the ESXi host to deploy the new appliance to, and administrative credentials, then click Next.


Enter the virtual appliance name, this is the name that appears in the vSphere inventory as mentioned earlier. The host name of the vCenter Server will be automatically migrated. Configure a root password and click Next.


Enter details for the Windows vCenter Server to be migrated. If you want to include migration of performance and historical data then tick the appropriate box (everything else is carried over by default) then click Next. If there are any extensions that require updating manually you will be warned about them here, click Yes to continue.


If the source Windows server was joined to a domain then enter the domain credentials and click Next.


Select the appliance size appropriate for your environment and click Next.


Select the datastore to locate the virtual appliance and click Next.

Configure the temporary network settings for the virtual appliance and click Next. These network settings are only used during migration of the data from the existing Windows server. Once data migration is complete the temporary network settings are discarded and the appliance assumes the network settings of the Windows VCS.


Select whether or not to join the VMware Customer Experience Improvement Program and click Next.


Review the summary page and click Finish.


The new VCSA will now be deployed and data migrated, once complete the Windows vCenter Server will be powered off. If you urgently need to power this back on to retrieve files or such like, then do so with the vNICs disconnected, otherwise you will cause an IP/host name conflict on the network.

You can connect to your upgraded vCenter using the same IP or FQDN; which has been migrated across, the temporary network settings are no longer in use. Verify the installed version is correct when selecting the vCenter under Hosts and Clusters, you can also go to Help > About.


If you are using the vSphere Windows client you will be prompted to upgrade your client to the latest version.

You must apply a new vCenter license key within 60 days: If you do not yet have a new license key you will need to upgrade the key through the My VMware portal:

Browse to https://my.vmware.com/web/vmware/login and login using the account which holds administrative access to your license estate. Click Manage License Keys and change the drop down menu to Upgrade License Keys. Browse to the existing license for vCenter Server 5 and select the tick box next to the license key you wish to upgrade, click Continue. Add the new license key to the vCenter Server Appliance using the vSphere client.


Web client: Click Hosts and Clusters and select the upgraded vCenter. Click Actions and Assign License. Select a license or use the green plus button to add a new license and click Ok.

Windows client: On the Home screen under Administration click vCenter Server Settings. Under licensing select a license or enter a new key under Assign a new license key to this vCenter Server and click Ok.

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