If you are having trouble with your Linked Mode group, consider the following points.

When you have multiple vCenter Server instances, each instance must have a working relationship with the domain controller and not conflict with another machine that is in the domain. Conflicts can occur, for example, when you clone a vCenter Server instance that is running in a virtual machine and you do not use sysprep or a similar utility to ensure that the cloned vCenter Server instance has a globally unique identifier (GUID).

If the domain controller is unreachable, vCenter Server might be unable to start. You might be unable to make changes to the Linked Mode configuration of the affected vCenter Server system.

If this occurs, resolve the problem with the domain controller and restart vCenter Server. If resolving the problem with the domain controller is not possible, you can restart vCenter Server by removing the vCenter Server system from the domain and isolating the system from its current Linked Mode group.

The DNS name of the machine must match with the actual machine name. Symptoms of machine names not matching the DNS name are data replication issues, ticket errors when trying to search, and missing search results from remote instances.

There is correct order of operations for joining a Linked Mode group.

a

Verify that the vCenter Server domain name matches the machine name. If they do not match, change one or both to make them match.

b

Update the URLs to make them compatible with the new domain name and machine name.

c

Join the vCenter Server system to a Linked Mode group.

If you do not update the URLs, remote instances of vCenter Server cannot reach the vCenter Server system, because the default vCenter Server URL entries are no longer accurate. See Configure the URLs on a Linked Mode vCenter Server System.

If a vCenter Server instance is no longer reachable by remote instances of vCenter Server, the following symptom might occur:

Clients logging in to other vCenter Server systems in the group cannot view the information that belongs to the vCenter Server system on which you changed the domain name because the users cannot log in to the system.

Any users that are currently logged in to the vCenter Server system might be disconnected.

Search queries do not return results from the vCenter Server system.

To resolve this issue, make sure that the Virtualcenter.VimApiUrl key points to the location where the vSphere Client and SDK clients can access the vCenter Server system, and the Virtualcenter.VimWebServicesUrl key points to the location where vCenter Server Webservices is installed. For the Virtualcenter.Instancename key, change the value so that the modified name appears in the vCenter Server inventory view.

If you cannot join a vCenter Server instance, you can resolve the problem with the following actions:

Ensure that the machine is grouped into the correct organizational unit in the corresponding domain controller.

When you install vCenter Server, ensure that the logged in user account has administrator privileges on the machine.

To resolve trust problems between a machine and the domain controller, remove the machine from the domain and then add it to the domain again.

To ensure that the Windows policy cache is updated, run the gpupdate /force command from the Windows command line. This command performs a group policy update.

If the local host cannot reach the remote host during a join operation, verify the following:

Remote vCenter Server IP address or fully qualified domain name is correct.

LDAP port on the remote vCenter Server is correct.

VMwareVCMSDS service is running.

Make sure your Windows and network-based firewalls are configured to allow Linked Mode.