Recently, I was able to upgrade a vCenter environment from 5.0 to 5.1. One of the major steps in this is the installation of the Single Sign-On service. This is an interesting installation as there are potentially a dozen gotcha’s before you even get to the install button. One of these said gotcha’s is this:

I got to a step where the installation wanted to talk to the newly created database named “RSA” (that I had created in an earlier step using some scripts). I had to formulate a jdbc (Yes, java) connection string so that it could successfully authenticate. During this process, I found that the application wanted to install two new users, an RSA_User and RSA_DBA to the database and configure permissions so that everything was secured around those two users correctly.

The problem I kept running into was an error that stated “Unable to authenticate to db”. That’s all. I was able to connect to said “db” using the same credentials I (thought) it was using. This didn’t happen to be the case. [more]

http://kb.vmware.com/kb/2035449

In my case, this error occurred because when the SQL instance was originally set up for the vCenter installation, it was set to use Windows Authentication only. For a vCenter 5.0 or prior installation, this is fine; however, for a vCenter 5.1, we’ve got to enable Mixed Mode authentication. I made the change on the instance, restarted services, and my installation continued (sort of) smoothly (not really, but that’s a Gotcha for another time).