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ludz1
Enthusiast
Enthusiast

Merging Two Different vCenter Server clusters into one

Hi Folks,

just looking for some views.

I've two separate VCSA's (both embedded psc) totally separate.(all servers are same make/model/processor/spec& and all on vsphere 6.0).

Cluster on vCenter1 has 5 hosts, Cluster on vCenter2 has 5 hosts.

All hosts are identical and patched into the same physical e/w networking switches.

vCenter1 and 2 both have individual vSAN's setup.

Both also have separate external iscsi storage.

My goal:

remove vCenter2 and move its 5 hosts under vCenter1 and create a 10 host cluster, and expand vSAN under vCenter1.

vCenter1 cluster1 & vCenter2 cluster2 have different ip ranges for mgmt, iscsi, vmotion, vsan.

My thoughts. export config from vCenter 2 vDS. create new vDS on vCenter1 and import config. (keeping two separate vDS's once complete.) (will this work? I've not tested yet).

Destroy vSAN on vCenter2 cluster2 hosts. (empty at present).

Mgmt IPs vmk0s can be left different for now. (or must I change them straight away)?

iSCSI IPs can be left the same as i'm leaving the external storage systems separate for the moment (plus they are housing the existing vm's).

Disconnect one host from vCenter2 and add it to vCenter1 cluster1. - change vMotion vmk IP on vSwitch and physical switch port. (same for vSAN)

Create new disk group and add to vSAN cluster. (repeat for other 4 hosts).

Once I have all 10 hosts on the one vSAN thats my shared storage so I can vmotion, off old storage and reconfigure.

Am I missing anything major?

Thanks

5 Replies
daphnissov
Immortal
Immortal

It's possible you may need to actually format those disks used by vSAN once you destroy the cluster. I'm not 100% on that one, but it certainly wouldn't hurt because vSAN won't wipe them out and that may cause problems when you go to add those as new disk groups.

ludz1
Enthusiast
Enthusiast

hhmm, point taken thanks, i'll look into that.

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arieldaveport
Enthusiast
Enthusiast

I recently moved some vSAN hosts to a new cluster and if you can I would destroy vSAN before add the hosts to vCenter1.

Your plan for the vDS will work too but idk if it is technically supported. Your endstate would be but if you can't get something to work during that process support would probably tell you not to do that. Once you import the vDS just leave it there until you add all the hosts and you can add them all the the vDS at the same time.

MGMT IPs dont every need to change assuming the networks are routable same for vMotion but it it was me I would basically re-IP everything on cluster 2 after you get it connected and add the VLANs on the uplinks. 

-Ariel
ludz1
Enthusiast
Enthusiast

Thanks for the input ,

I presume disabling vSAN and deleting the disk groups is sufficient to reclaiming the local disks?

I confirmed with VMware that creating the new vDS and exporting/importing the config is supported.

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arieldaveport
Enthusiast
Enthusiast

That's good new on the vDS!

If you do a clean decom on vsan you should be good, if you don't see the disks as available try the steps in the link. https://cormachogan.com/2014/02/18/vsan-part-16-reclaiming-disks-for-other-uses/

-Ariel
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