OpenStack Havana is installed on machines rented from OVH and Hetzner. An aggregate is created for machines hosted at OVH and another for machines hosted at Hetzner. A Ceph cluster is created with a pool using disks from OVH and another pool using disks from Hetzner. A cinder backend is created for each Ceph pool. From the dashboard, an instance can be created in the OVH availability zone using a Ceph volume provided by the matching OVH pool.
Creating availability zones
The availability zones are created as a side effect of creating an aggregate.
# nova aggregate-create ovh ovh
+----+------+-------------------+-------+--------------------------------+
| Id | Name | Availability Zone | Hosts | Metadata |
+----+------+-------------------+-------+--------------------------------+
| 2 | ovh | ovh | [] | {u'availability_zone': u'ovh'} |
+----+------+-------------------+-------+--------------------------------+
# nova aggregate-create hetzner hetzner
+----+---------+-------------------+-------+------------------------------------+
| Id | Name | Availability Zone | Hosts | Metadata |
+----+---------+-------------------+-------+------------------------------------+
| 3 | hetzner | hetzner | [] | {u'availability_zone': u'hetzner'} |
+----+---------+-------------------+-------+------------------------------------+
The hosts are assigned to their availability zone:
# nova aggregate-add-host ovh bm0015.the.re
Aggregate 2 has been successfully updated.
+----+------+-------------------+--------------------+--------------------------------+
| Id | Name | Availability Zone | Hosts | Metadata |
+----+------+-------------------+--------------------+--------------------------------+
| 2 | ovh | ovh | [u'bm0015.the.re'] | {u'availability_zone': u'ovh'} |
+----+------+-------------------+--------------------+--------------------------------+
The result can be checked with
# nova availability-zone-list +-----------------------+----------------------------------------+ | Name | Status | +-----------------------+----------------------------------------+ | internal | available | | |- bm0015.the.re | | | | |- nova-conductor | enabled :-) 2013-11-11T14:26:43.000000 | | | |- nova-consoleauth | enabled :-) 2013-11-11T14:26:43.000000 | | | |- nova-scheduler | enabled :-) 2013-11-11T14:26:43.000000 | | | |- nova-cert | enabled :-) 2013-11-11T14:26:43.000000 | | ovh | available | | |- bm0015.the.re | | | | |- nova-compute | enabled :-) 2013-11-11T14:26:48.000000 | | hetzner | available | | |- bm0016.the.re | | | | |- nova-compute | enabled :-) 2013-11-11T14:26:49.000000 | | nova | available | +-----------------------+----------------------------------------+
Creating the Ceph pools
The crush map is extracted with
ceph osd getcrushmap -o crush.bin crushtool -d crush.bin -o crush.txt
It is edited to add
datacenter ovh {
id -5
alg straw
hash 0
item bm0014 weight 1.820
item bm0015 weight 1.820
}
rule ovh {
ruleset 3
type replicated
min_size 1
max_size 10
step take ovh
step chooseleaf firstn 0 type host
step emit
}
and sent back to the Ceph monitors with
crushtool -c crush.txt -o crush.bin ceph osd setcrushmap crush.bin
An ovh pool is created and set to use the ovh ruleset:
ceph osd pool create ovh 128 ceph osd pool set ovh crush_ruleset 3
The crush.txt file also contains the ruleset for the hetzner pool.
Creating cinder backends
In the /etc/cinder/cinder.conf file of the host running cinder-volume, one cinder backend is defined for each Ceph pool:
enabled_backends=rbd-hetzner,rbd-ovh [rbd-hetzner] volume_driver=cinder.volume.driver.RBDDriver rbd_pool=hetzner volume_backend_name=RBD_HETZNER [rbd-ovh] volume_driver=cinder.volume.driver.RBDDriver rbd_pool=ovh volume_backend_name=RBD_OVH
In order to enable the –volume-type ovh option of cinder create, the corresponding type keys must be created:
# cinder type-create ovh
+--------------------------------------+------+
| ID | Name |
+--------------------------------------+------+
| 48645332-4835-4a9b-9078-cd735f47dae5 | ovh |
+--------------------------------------+------+
# cinder type-key ovh set volume_backend_name=RBD_OVH
# cinder extra-specs-list
+--------------------------------------+---------+------------------------------------------+
| ID | Name | extra_specs |
+--------------------------------------+---------+------------------------------------------+
| 48645332-4835-4a9b-9078-cd735f47dae5 | ovh | {u'volume_backend_name': u'RBD_OVH'} |
+--------------------------------------+---------+------------------------------------------+
Check that the cinder scheduler is set as follows in /etc/cinder/cinder.conf
scheduler_driver=cinder.scheduler.filter_scheduler.FilterScheduler
Assembling instance and volume
After creating a volume using the OVH cinder backend:
cinder create --volume-type ovh --display-name test 1
An instance is created in the OVH availability zone:
nova boot --availability-zone ovh \
--image 'cirros image' \
--key-name key_loic \
--nic net-id=e1d72366-1f25-42c1-a953-a944c9f932e3 \
--flavor m1.tiny --poll try
The volume is attached to the instance
nova volume-attach try 045d1cae-cd9b-4d64-b0b8-544f5b6d0c5a /dev/vdb