12-07-2011 02:35 AM - edited 03-01-2019 10:11 AM
We have UCS and Nexus 1000v running in our production. Due to some problem with the vCenter server, we need to re-install the vCenter server.
Would like to know what should we do on the Nexus 1000v as re-installing the vCenter will cause the svs connection to break. Any way to do it without any disruption to the existing VMs?
Please share your experience or comment. Thanks in advance.
12-07-2011 04:05 AM
Its an involved process that will require backing the hosts out of the vDS, migrating to vSwitch, adding everything to the new vCenter and migrating it back to nexus 1000v.
Take a look at the following KB article
Are you having to install everything for vCenter including it's database?
louis
12-07-2011 05:40 AM
yes. everything including it's database.
looking at the article, there will be some downtime when changing from Nexus 1000v to standard vSwitch. this will be the last option.
12-07-2011 04:40 AM
Being on UCS you have some options here but need to know what your current configuration is.
how many UCS vNICs are presented to ESXi?
are you using VMware standard vSwitches for management and vMotion and N1KV for VMs?
12-07-2011 05:44 AM
we have 2 ESXi. with 6 vNICs configured.
4 for production (used for VM) under Nexus 1000v.
2 for vkernal (management & vMotion) under vSwitch.
12-07-2011 10:41 AM
Great, here is how I would do it with no downtime. I have done this a few times so I know it works.
12-07-2011 04:33 PM
sounds workable... but involve lots of changes, not sure the change request will be approved.
another issue is we only have 2 hosts and it is insufficient resources to handle all VM by 1 host.
thanks anyway for the suggestion...
12-07-2011 05:52 AM
i just wondering whether we can perform the following:
- Disconnect the svs connection.
- Remove the svs connection configuration.
- Re-configure & re-connect the svs configuration after the vCenter has been re-installed.
my understanding is the Nexus 1000v will still be working if the vCenter is down right? correct me if i'm wrong. thanks.
12-07-2011 06:02 AM
The problem will be that the vDS config on the hosts will not match with vCenter. The hosts will say they have a stale vDS and you'll never be able to see or modify anything to do with the vDS on the ESX hosts in vCenter.
vCenter can't import old vDS data. When you install a new vCenter the vDS data is completely new and does not match what is on the hosts.
Traffic will continue to flow but the hosts nothing will ever look correct in vCenter and you will not be able to make any changes to VMs or ESX hosts.
Its frustrating I know. We are tying to find a way to export old vDS data and import it back into vCenter.
louis
12-07-2011 04:34 PM
that is too bad.. if really got to re-do the Nexus 1000v, i'll have to re-host the license right? as the host ID will change.
12-07-2011 04:37 PM
even better, with only 2 hosts no reason to use host profiles or go into maintenance mode just make the change manualy on each host
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12-07-2011 04:43 PM
no, you can use the same VSMs just redo the svs connection to vcenter
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12-07-2011 04:52 PM
i just wondering whether we can perform the following:
- Disconnect the svs connection.
- Remove the svs connection configuration.
- Re-configure & re-connect the svs configuration after the vCenter has been re-installed.
but the comment from louis says:
The problem will be that the vDS config on the hosts will not match with vCenter. The hosts will say they have a stale vDS and you'll never be able to see or modify anything to do with the vDS on the ESX hosts in vCenter.
vCenter can't import old vDS data. When you install a new vCenter the vDS data is completely new and does not match what is on the hosts.
Traffic will continue to flow but the hosts nothing will ever look correct in vCenter and you will not be able to make any changes to VMs or ESX hosts.
Its frustrating I know. We are tying to find a way to export old vDS data and import it back into vCenter.
12-07-2011 04:58 PM
no, that will not work. safest option is to migrate to a standard vSwitch, remove hosts from N1KV, rebuild vcenter, recreate svs connection and then migrate back. you can do all of this with no downtime.
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12-07-2011 04:56 PM
For VSM you are fine. You can disconnect and reconnect. It's the ESX hosts that will be stale. You need to first remove them(ESX hosts) from the vDS by migrating everything to vSwitch as was previously stated
The VSM will be fine with a disconnect and reconnect.
louis
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