Can someone explain how deploying a template works under the covers? I ask because we currently have 3 ESX hosts that can only see three Tier1 datastores. All of our templates reside on Tier2 datastores presented to 5 different ESX hosts. However, we ARE able to deploy that template on Tier2 over to the Tier1 ESX host/datastore. That tells me that deploying from a template must be more of a network related operation rather than copying from one datastore to another. FYI, Tier1 is using IBM SVC and Tier2 is Netapp; we are also running ESX 3.5 and VC 2.5 u4
So I think I figured out that the reason why is because both clusters/hosts access the same network that the template currently resides on. However, that makes me wonder which Tcp/udp ports are used for the operation.
Templates must be on shared storage.
ESX does not use use network ports, but simple make a "clone" of a VM by copying all the file (for this reason the node must see both the source and the destination datastore).