Nova Cells v2
- https://bugs.launchpad.net/nova/+bug/1656276 - Error running nova-manage cell_v2 simple_cell_setup when configuring nova with puppet-nova
- https://bugs.launchpad.net/nova/+bug/1649341 - Undercloud upgrade fails with "Cell mappings are not created, but required for Ocata"
- Fixed on master in Nova, backport proposed to stable/newton. However, this change caused issues for TripleO on master which is bug 1656276 above.
- https://bugs.launchpad.net/nova/+bug/1656017 - nova-manage cell_v2 map_cell0 always returns a non-0 exit code
- The deployment/upgrade process needs to be documented in more than just the release notes.
- dansmith was going to work on a blog post to start this.
- On a side note, we should also have man pages for the cell_v2 commands because there is confusion around the inputs and outputs and how return codes should be treated, i.e. is 1 an error or not?
- alaski's older docs patch (which is probably out of date now but might be useful) is here: https://review.openstack.org/#/c/267153/
- Integrate the 'nova-status upgrade check' CLI into the CI/QA system (grenade).
- Older tracking etherpads (these may be out of date):
- Should the computes self-register with a cell when the compute_nodes record is created from the ResourceTracker? https://review.openstack.org/#/c/369634/
- How would the computes know which cell to map to? We could add something to the model to flag a 'default' or 'staging' cell mapping, or put something into nova.conf on the compute node.
- If we auto-register into a default/staging cell, how do we move hosts to other cells? nova-manage CLI?
- Why can't we create an empty cell, i.e. a cell mapping with no computes? This is a fresh-install scenario.
- Note that the nova-status upgrade check command does not consider it a failure if there are cell mappings but no compute nodes yet but simple_cell_setup does consider that a failure, see bug 1656276.
- There has been a review up for this for awhile: https://review.openstack.org/#/c/332713/
- This way, a fresh install would do something like: 'nova-manage cell_v2 map_cell0' 'nova-manage cell_v2 create_cell' and then once compute hosts are available, operator runs 'nova-manage cell_v2 discover_hosts'
DB Table Analysis
- Otherwise see the cells v2 section in the Ocata review priorities etherpad: https://etherpad.openstack.org/p/ocata-nova-priorities-tracking
- Note the original cells wiki is here: https://wiki.openstack.org/wiki/Blueprint-nova-compute-cells
- Kilo design summit etherpad: https://etherpad.openstack.org/p/kilo-nova-cells
- nova-specs: https://review.openstack.org/#/q/status:open+project:openstack/nova-specs+branch:master+topic:bp/cells-instance-mapping,n,z
- Flow diagrams: http://paste.openstack.org/show/144068/
- https://etherpad.openstack.org/p/nova-cells-flow-diagram commentable version