Nova Multi-Cell Live Migration Issues
Hello All, I'm trying to get a 2 cell setup going as a test environment and am running into some troubles. I seem to be able to start VM's just fine, however when I try live-migrations I am getting this error: 2026-02-19 20:11:01.448 1 ERROR nova.conductor.manager [None req-91d4c1c6-a69f-41d4-a3ca-c0890bde0af8 - - - - - -] Migration of instance 73123ed9-d112-4030-945c-96c75a016d55 to host compute1 unexpectedly failed.: oslo_messaging.rpc.client.RemoteError: Remote error: RemoteError Remote error: CantStartEngineError No sql_connection parameter is established I see this on the following service logs nova-conductor (superconductor role only) nova-api nova-compute What is odd is that I don't see any activity in the cell-conductor when this happens, even with debug enabled. Here are the configured connection strings I have in each conductor/api/compute services: https://pastebin.com/raw/uuamtzsk Are these the correct database connection strings for each service? I'm basing this off the multi-cell diagram in the docs. The fact that the cell-conductors aren't showing any activity when this happens is throwing me off. I feel like I'm missing something here but I can't put my finger on it. Any help would be appreciated, thanks!
Hello All,
I'm trying to get a 2 cell setup going as a test environment and am running into some troubles. I seem to be able to start VM's just fine, however when I try live-migrations I am getting this error:
2026-02-19 20:11:01.448 1 ERROR nova.conductor.manager [None req-91d4c1c6-a69f-41d4-a3ca-c0890bde0af8 - - - - - -] Migration of instance 73123ed9-d112-4030-945c-96c75a016d55 to host compute1 unexpectedly failed.: oslo_messaging.rpc.client.RemoteError: Remote error: RemoteError Remote error: CantStartEngineError No sql_connection parameter is established
I see this on the following service logs nova-conductor (superconductor role only) nova-api nova-compute
What is odd is that I don't see any activity in the cell-conductor when this happens, even with debug enabled. so are you tryign to live migrate across cells?
On 20/02/2026 04:26, Tyler Wilson wrote: that is not supproted in nova. the only cross cell move operation is resize/colde migrtaion live migration is only supproted between hosts in the same cell.
Here are the configured connection strings I have in each conductor/api/compute services: https://pastebin.com/raw/uuamtzsk
you shouold be able to move form compute1<>compute3 but not to/from compute2
Are these the correct database connection strings for each service? I'm basing this off the multi-cell diagram in the docs. The fact that the cell-conductors aren't showing any activity when this happens is throwing me off. I feel like I'm missing something here but I can't put my finger on it.
the db and rabbit urls connections look ok i should also note thract cross cell migration is block for everyone by defualt. if you want to use it you need to update teh policy rule to allow admins to do it.
Any help would be appreciated, thanks!
Hello Sean, Thanks for the reply. This is indeed going from compute3<->compute1 so it's within the same cell. I've gathered some logs during the migration process: https://pastebin.com/raw/0zmAt65n Note that I did not include the cell-level conductor as there was no output during the time. Thanks for any assistance you can provide. On Fri, Feb 20, 2026 at 9:17 AM Sean Mooney <smooney@redhat.com> wrote:
Hello All,
I'm trying to get a 2 cell setup going as a test environment and am running into some troubles. I seem to be able to start VM's just fine, however when I try live-migrations I am getting this error:
2026-02-19 20:11:01.448 1 ERROR nova.conductor.manager [None req-91d4c1c6-a69f-41d4-a3ca-c0890bde0af8 - - - - - -] Migration of instance 73123ed9-d112-4030-945c-96c75a016d55 to host compute1 unexpectedly failed.: oslo_messaging.rpc.client.RemoteError: Remote error: RemoteError Remote error: CantStartEngineError No sql_connection parameter is established
I see this on the following service logs nova-conductor (superconductor role only) nova-api nova-compute
What is odd is that I don't see any activity in the cell-conductor when this happens, even with debug enabled. so are you tryign to live migrate across cells?
On 20/02/2026 04:26, Tyler Wilson wrote: that is not supproted in nova. the only cross cell move operation is resize/colde migrtaion
live migration is only supproted between hosts in the same cell.
Here are the configured connection strings I have in each conductor/api/compute services: https://pastebin.com/raw/uuamtzsk
you shouold be able to move form compute1<>compute3 but not to/from compute2
Are these the correct database connection strings for each service? I'm basing this off the multi-cell diagram in the docs. The fact that the cell-conductors aren't showing any activity when this happens is throwing me off. I feel like I'm missing something here but I can't put my finger on it.
the db and rabbit urls connections look ok
i should also note thract cross cell migration is block for everyone by defualt. if you want to use it you need to update teh policy rule to allow admins to do it.
Any help would be appreciated, thanks!
participants (2)
-
Sean Mooney
-
Tyler Wilson