This is a quick and a simple note to inform you about an issue which could eat up your precious time while deploying vCenter 6.0 or upgrading to vCenter 6.0 from a previous release within an available upgrade path.
I have vCenter 5.5 u2 running in my lab as vCenter Server Virtual Appliance (VCSA). The plan was to upgrade to the new and shiny vCenter 6.0 virtual appliance. If you have not looked into the documentation yet, then I must inform you that the process of upgrade requires you to install the Client Integration Plugin. I will not re-invent the wheel as Vladan Seget has already written a detailed article as to how you can do this upgrade here.
While I was trying to do this upgrade, I ran into an issue where after installing the Integration Client, the upgrade requires you to launch a webpage which is called VCSA-SETUP.HTML located in the setup folder which you extract from the ISO of vCenter 6.0. As soon as you launch this webpage, you are suppose to get a screen which allows you to either install a new VCSA appliance or upgrade the existing version running in your environments.