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FreddyFredFred
Hot Shot
Hot Shot

questions about vDS and management

Hello,

I'm new to distributed switches and I'm a little worried about management in the case of a failure.

From what I have read it appears some people put management on standard switches so they still have some access in the event of a problem. Is this the management (vmkernel) of each host or just the network the vcenter server (assuming it's a VM) is on or both?

I've also seen comments about running vcenter on a vDS but using an ephemeral port for just the vcenter server. Would this be about the same as using a standard switch?

What happens if a host dies completely and I need to rebuild it? Can it be rebuilt and added back to the vDS or will that cause a problem/confusion for the vDS? From a little testing I did, I can disconnect a host and then remove it without migrating vmkernel ports, but can a failed host be disconnected? (thankfully I've never been in a situation to have to try so I'm not sure)

My only concern with putting managment outside of my vDS (whiich will be on 10gig connections), is only having 1gig and the potential for vmotion in certain cases to be much slower. Am I worrying for nothing about for nothing about the speed, about the management?

Any insights or advice are appreciated.

Thanks

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chriswahl
Virtuoso
Virtuoso

I've also seen comments about running vcenter on a vDS but using an ephemeral port for just the vcenter server. Would this be about the same as using a standard switch?

Not entirely; the control plane is still distributed, but port creation has been delegated to the hosts for outage scenarios. See: Protecting a Distributed Switch with Ephemeral Binding - Wahl Network

What happens if a host dies completely and I need to rebuild it? Can it be rebuilt and added back to the vDS or will that cause a problem/confusion for the vDS?


If a host dies, there will not be any VMs on it to worry about - hopefully, you have HA enabled and the workloads are running on another host in your cluster. When you rebuild (reinstall) the hypervisor and add it to vCenter, you can then add it back into the VDS.

From a little testing I did, I can disconnect a host and then remove it without migrating vmkernel ports, but can a failed host be disconnected? (thankfully I've never been in a situation to have to try so I'm not sure)

Yes. You can remove a failed host from vCenter, even if it is part of a VDS.

VCDX #104 (DCV, NV) ஃ WahlNetwork.com ஃ @ChrisWahl ஃ Author, Networking for VMware Administrators
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