In vmotion config the gateway is not specific to the VMotion network CIDR, in the add network wizard it defaults to the vmkernel mgmt connection gateway. I assume this is because all hosts use the same network for vmotion therefore no gateway is really needed.
What if I have 1 host in the cluster that needs to be on a different network for mgmt and vmotion than the others?
1) do I have to check the box to "Override default gateway for this adapter" for all hosts in the cluster in order for them to be able to vmotion to this 1 host that is different?
We are about to rewire all hosts to new switches and move to new VLANs, and I need to do this gracefully without disruption in service. I figure I can do one host in the cluster at a time, and when I vmotion VMs over to it I will change the portgroup assignment using the migration wizard. I just want to validate what I need to do to keep vmotion working when 1 of the hosts in the cluster is now using a different VLAN for its vmotion interface.
You can have only one Default Gateway in the default TCP/IP stack, so don't try to override the shown gateway in the vMotion port groups, as this will "kill" your Management Network.
What you may want tolook at, is to disable (uncheck) vMotion on the currently configured port groups, and use/create a separate vMotion TCP/IP stack for it. See https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.vcenterhost.doc/GUID-5211FD4B-256B-...
Our existing vmotion network is non routable, so this would need to be changed.
Once the above is done, I think you are stating to merely create a new vmotion portgroup and no custom gateway is needed.
host on vmotion network X will be able to migrate to vmotion network Y without issues. I know at some point in the life span of VMware vCenter vmotion became routable and was no longer confined to a single network.
Is this correct?
To be honest your reply about how using a custom gateway for the vmotion IP will kill the mgmt network defies basic network logic to me, how does a host communicate to another network without a proper gateway that belongs to that network? And why would the option to use a different gateway even be present in the wizard if this is the case?