With vCenter 1.2 and ESX server 2.5.1 when you add an ESX Host to farm it adds a vmware-ccagent process. This vmware-ccagent replaces vmware-serverd. The agent allows the vCenter Server together with vCenter client to make changes to the ESX server. If you do a clean install of vCenter 1.3 and ESX 2.5.2 – the vmware-ccagent will not be there. The agent has been discontinued and its functionality has been incorporated into vmware-serverd. If you have upgraded from ESX 2.x to ESX 2.5.2, and it was previously part of a vCenter farm, you will find that vmware-ccagent is still there.