Ceph pools are defined to collocate volumes and instances in OpenStack Havana. For volumes that do not need the resilience provided by Ceph, a LVM cinder backend is defined in /etc/cinder/cinder.conf:
[lvm] volume_group=cinder-volumes volume_driver=cinder.volume.drivers.lvm.LVMISCSIDriver volume_backend_name=LVM
and appended to the list of existing backends:
enabled_backends=rbd-default,rbd-ovh,rbd-hetzner,rbd-cloudwatt,lvm
A cinder volume type is created and associated with it:
# cinder type-create lvm
+--------------------------------------+------+
| ID | Name |
+--------------------------------------+------+
| c77552ff-e513-4851-a5e6-2c83d0acb998 | lvm |
+--------------------------------------+------+
# cinder type-key lvm set volume_backend_name=LVM
# cinder extra-specs-list
+--------------------------------------+-----------+--------------------------------------------+
| ID | Name | extra_specs |
+--------------------------------------+-----------+--------------------------------------------+
...
| c77552ff-e513-4851-a5e6-2c83d0acb998 | lvm | {u'volume_backend_name': u'LVM'} |
...
+--------------------------------------+-----------+--------------------------------------------+
To reduce the network overhead, a backend availability zone is defined for each bare metal by adding to /etc/cinder/cinder.conf:
storage_availability_zone=bm0015
and restarting cinder-volume:
# restart cinder-volume # sleep 5 # cinder-manage host list host zone ... bm0015.the.re@lvm bm0015 ...
where bm0015 is the hostname of the machine. To create a LVM backed volume that is located on bm0015:
cinder create --availability-zone bm0015 --volume-type lvm --display-name test 1
In order for the allocation of RBD volumes to keep working without specifying an availability zone, there must be at least one cinder volume running in the default availability zone ( nova presumably ) and configured with the expected RBD backends. This can be checked with:
# cinder-manage host list | grep nova ... bm0017.the.re@rbd-cloudwatt nova bm0017.the.re@rbd-ovh nova bm0017.the.re@lvm nova bm0017.the.re@rbd-default nova bm0017.the.re@rbd-hetzner nova ...
In the above the lvm volume type is also available in the nova availability zone and is used as a catch all when a LVM volume is prefered but collocating it on the same machine as the instance does not matter.