vCenter Single Sign-On installer reports the error: Error 29155.Identity source discovery error (2034374)

Symptoms

When installing vCenter Server 5.1, you experience these symptoms:

• During the installation, an attempt is made to automatically discover an Active Directory domain
• While discovering Identity Sources as part of the vCenter Single Sign-On install, you see the error:
  
  Error 29155.Identity source discovery error
  
• When you click OK in the error dialog, the vCenter Single Sign-On installation continues despite the message
• Subsequent component installations may fail as the machine is not joined to a domain

Cause

This issue occurs because automatic discovery of an Active Directory domain can sometimes fail, usually due to environmental reasons such as security restrictions.

Resolution

This is a known issue, and is currently being reviewed by VMware. This article will be updated as information becomes available. For related information see the Known issues section in the VMware vCenter Server 5.1.0a release notes.

To work around this issue when you are not able to upgrade, manually add an identity source.

To manually add an identity source:

1. Skip ahead in installation components and install the vSphere Web Client after the vCenter Single Sign-On installation completes.
2. Manually add a domain as an identity source using the admin@system-domain account. For more information, seeAdd a vCenter Single Sign-On Identity Source in the vSphere 5.1 Documentation Center.
3. Resume installing any components that failed to install previously.

Source:-

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2034374