Which users can log in to vCenter Server after an upgrade depends on the version that you are upgrading from and the deployment configuration.

In upgrades to vCenter Server 5.0 and earlier, which do not include a vCenter Single Sign-On service, both the local operating system users and Active Directory users that are registered with vCenter Server continue to work with the upgraded vCenter Server.

This behavior changes if you are upgrading from a version that does not include vCenter Single Sign-On to a version that does include vCenter Single Sign-On: vCenter Server version 5.1 or vCenter Server version 5.5.

Note

With vCenter Single Sign-On, local operating system users become far less important than the users in a directory service such as Active Directory. As a result, it is not always possible, or even desirable, to keep local operating system users as authenticated users.

After the upgrade from a version earlier than version 5.1, you might be prompted for the administrator of the root folder in the vSphere inventory hierarchy during installation. This might happen because of changes in user stores from pre-5.1 versions to 5.1 and later versions of vSphere. See Hierarchical Inheritance of Permissions.

A Simple Install upgrade installs or upgrades a single vCenter Server and related components.

If you upgrade to vCenter Server 5.5 from a vCenter Server version that does not include vCenter Single Sign-On, vCenter Single Sign-On recognizes existing local operating system users. In addition, the user administrator@vsphere.local can log in as an administrator user to vCenter Single Sign-On and vCenter Server. If your previous installation supported Active Directory users, you can add the Active Directory domain as an identity source.

If you upgrade vCenter Single Sign-On and vCenter Server, vCenter Single Sign-On recognizes existing local operating system users. In addition, the user administrator@vsphere.local can log in to vCenter Single Sign-On and vCenter Server as an administrator user. If your previous installation included an Active Directory domain as an identity source, that identity source is still available after the upgrade. Because vCenter Server supports only one default identity source, users might have to specify the domain when they log in (DOMAIN\user).

A custom upgrade might install different vCenter Server components on different machines or install a second vCenter Server system on the same machine. You also use Custom Install to upgrade an environment that is installed in different locations.

If you upgrade to vCenter Server 5.5 from a vCenter Server version that does not include vCenter Single Sign-On, and you install vCenter Single Sign-On on a different machine than vCenter Server, vCenter Single Sign-On does not recognize existing local operating system users. The user administrator@vsphere.local can log in to vCenter Single Sign-On and vCenter Server as an administrator user. If your previous installation supported Active Directory users, you can add the Active Directory domain as an identity source.

If you are upgrading vCenter Server from a version that includes vCenter Single Sign-On in multisite mode, and if the different vCenter Server systems use Linked mode, you must resynchronize first. You can then upgrade all vCenter Single Sign-On instances and maintain Linked Mode functionality. Linked Mode is required for a single view of all vCenter Server systems. Multisite vCenter Single Sign-On is supported only if all nodes are the same version.

If you are upgrading vCenter Server from a version that includes vCenter Single Sign-On in high availability mode, you must upgrade all of the vCenter Single Sign-On high availability instances. Perform the upgrade first, and configure high availability by protecting both vCenter Server and vCenter Single Sign-On with VMware HA or VMware Heartbeat after the upgrade is complete.

Note

When you install the vCenter Single Sign-On component that is included with vCenter Server version 5.5 in multiple locations, the VMware Directory Service is updated for all vCenter Single Sign-On instances if you make a change in one location.