[NOVA] There is no method to delete non-empty cells or "cell mappings".

[Saurabh jangir]

We have several method to create cells and mapping cell with hosts, database and message queue but there's no method to delete the non-empty cells in nova.
We can delete the empty cells through "nova-manage cell_v2 delete_cell --cell_uuid <cell_uuid>". But if cell is mapped to hosts, we don't have any CLI or method to delete that cell because to delete any cell we first need to remove its mapping with hosts.
For it to be resolved first we need a method to delete cell mappings.

[jichenjc (jichenjc)]

this looks like a reuqiremnets, not a bug, what kind of use case to delete a cell mapping or non-empty cell? remove host from cell?

[Saurabh jangir (sjopenstack)]

@jichenjic to delete a non-empty cell we need to delete its mapping to hosts/instance first. Which actually means that we need to remove hosts from cell. then only we can delete any cell.

One thing can be done here. We have a CLI to delete an empty cell - "nova-manage cell_v2 delete_cell --cell_uuid <cell_uuid>". we can append "-f" or "--force" to that existing command to first delete all the mappings and then removing cells.

[jichenjc (jichenjc)]

thanks for the detailed info, maybe that's an use case that I am can't image, maybe we need delete an cell and create a new one then make all hosts to the new cell? anyway I think it's a requirements other than a bug...

[Saurabh jangir (sjopenstack)]

~jichenjc I found a same bug reported earlier. Pls have a look @ https://bugs.launchpad.net/nova/+bug/1656691.