In my daily reboots, I'm coming across a few weird VMs that should be on
ceph but instead are using local storage on hypervisors. I've tracked
this down to particular flavors which don't specify the Ceph backend.
For example, here's a 'good' flavor:


root@cloudcontrol1003:~# openstack flavor show g3.cores4.ram8.disk20
+----------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------+
| Field                      | Value |
+----------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------+
| OS-FLV-DISABLED:disabled   | False |
| OS-FLV-EXT-DATA:ephemeral  | 0 |
| access_project_ids         | None |
| description                | None |
| disk                       | 20 |
| id                         | c14b5856-5e6a-4f7a-8125-ace4f616c299 |
| name                       | g3.cores4.ram8.disk20 |
| os-flavor-access:is_public | True |
| properties                 |
aggregate_instance_extra_specs:ceph='true',
quota:disk_read_iops_sec='5000', quota:disk_total_bytes_sec='200000000',
quota:disk_write_iops_sec='500' |
| ram                        | 8192 |
| rxtx_factor                | 1.0 |
| swap | |
| vcpus                      | 4 |
+----------------------------+------------------------------------------------------------------------------------------------------------------------------------------------------+

...and here's a bad one...


root@cloudcontrol1003:~# openstack flavor show g3.cores24.ram122.disk20
+----------------------------+--------------------------------------+
| Field                      | Value                                |
+----------------------------+--------------------------------------+
| OS-FLV-DISABLED:disabled   | False                                |
| OS-FLV-EXT-DATA:ephemeral  | 0                                    |
| access_project_ids         | ['wikiwho']                          |
| description                | None                                 |
| disk                       | 20                                   |
| id                         | 6207fade-5517-4ac4-a147-6ae0c8fa1384 |
| name                       | g3.cores24.ram122.disk20             |
| os-flavor-access:is_public | False                                |
| properties |                                      |
| ram                        | 124928                               |
| rxtx_factor                | 1.0                                  |
| swap |                                      |
| vcpus                      | 24                                   |
+----------------------------+--------------------------------------+


Note the lack of properties set on the latter.

We should definitely investigate whether to have flavors without
properties have good defaults -- at this point we're setting those same
properties for almost every flavor which seems silly.  In the meantime,
though, it's important that those properties be specified on new
flavors, otherwise VMs with those flavors can be consigned to purgatory
and weird behavior.

The docs about flavor creation are here:

https://wikitech.wikimedia.org/wiki/Portal:Cloud_VPS/Admin/VM_flavors#General_flavor_guidelines

most likely that should be duplicated or linked from other places though.


Thanks!

-A
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