I've been searching around but haven't found a clear answer on this.
We're using VMware ESXI with vSphere to manage a handful of VMs (about 15 right now) However, these are all spread over three separate machines. I'm looking for a way to cluster these together so their resources can be pooled or dynamically allocated. I found vSphere DRS Cluster information, but I'm having a really hard time finding out what I need to get that set up.
Does it require a separate vCenter license to hook into vSphere? And at that point, how do I create a database to group all the server hosts together? Every tutorial I find already has 2+ host machines already grouped together in the vSphere client, and I'm not sure how to go about achieving that.
If you just want to create a failover cluster, then you need VMware HA. VMware DRS is the option for resource dynamical allocation. To manage these two options, you need a vCenter Server. vCenter Server Foundation can manage up to 3 hosts (which is your case). For more information about vCenter, see this link.
For VMware HA and DRS to work, you must have a shared storage (NFS, iSCSI, or Fiber Channel). To know how to create VMware HA cluster using vSphere Client (connected to vCenter Server), see this link.
VMware DRS is an option after you created VMware HA. See this link