Block Device to OpenStack Guide

Procedure

1. Verify the Red Hat Ceph Storage cluster is running, and is in a HEALTH_OK state:

   [root@mon ~]# ceph -s

2. Create the Ceph pools:

   Example

   [root@mon ~]# ceph osd pool create volumes 128
   [root@mon ~]# ceph osd pool create backups 128
   [root@mon ~]# ceph osd pool create images 128
   [root@mon ~]# ceph osd pool create vms 128

   In the above example, 128 is the number of placement groups.

   Important

   Red Hat recommends using the Ceph Placement Group’s per Pool Calculator to calculate a suitable number of placement groups for the pools.

Procedure

1. On the OpenStack Nova, Cinder, Cinder Backup nodes install the following packages:

   [root@nova ~]# yum install python-rbd
   [root@nova ~]# yum install ceph-common

2. On the OpenStack Glance node install the python-rbd package:

   [root@glance ~]# yum install python-rbd

Procedure

1. Copy the Ceph configuration file from the Ceph Monitor node to the OpenStack Nova, Cinder, Cinder Backup and Glance nodes:

   [root@mon ~]# scp /etc/ceph/ceph.conf OPENSTACK_NODES:/etc/ceph

Procedure

1. From a Ceph Monitor node, create new users for Cinder, Cinder Backup and Glance:

   [root@mon ~]# ceph auth get-or-create client.cinder mon 'allow r' osd 'allow class-read object_prefix rbd_children, allow rwx pool=volumes, allow rwx pool=vms, allow rx pool=images'
   
   [root@mon ~]# ceph auth get-or-create client.cinder-backup mon 'allow r' osd 'allow class-read object_prefix rbd_children, allow rwx pool=backups'
   
   [root@mon ~]# ceph auth get-or-create client.glance mon 'allow r' osd 'allow class-read object_prefix rbd_children, allow rwx pool=images'

2. Add the keyrings for client.cinder, client.cinder-backup and client.glance to the appropriate nodes and change their ownership:

   [root@mon ~]# ceph auth get-or-create client.cinder | ssh CINDER_VOLUME_NODE sudo tee /etc/ceph/ceph.client.cinder.keyring
   [root@mon ~]# ssh CINDER_VOLUME_NODE chown cinder:cinder /etc/ceph/ceph.client.cinder.keyring
   
   [root@mon ~]# ceph auth get-or-create client.cinder-backup | ssh CINDER_BACKUP_NODE tee /etc/ceph/ceph.client.cinder-backup.keyring
   [root@mon ~]# ssh CINDER_BACKUP_NODE chown cinder:cinder /etc/ceph/ceph.client.cinder-backup.keyring
   
   [root@mon ~]# ceph auth get-or-create client.glance | ssh GLANCE_API_NODE sudo tee /etc/ceph/ceph.client.glance.keyring
   [root@mon ~]# ssh GLANCE_API_NODE chown glance:glance /etc/ceph/ceph.client.glance.keyring

3. OpenStack Nova nodes need the keyring file for the nova-compute process:

   [root@mon ~]# ceph auth get-or-create client.cinder | ssh NOVA_NODE tee /etc/ceph/ceph.client.cinder.keyring

4. The OpenStack Nova nodes also need to store the secret key of the client.cinder user in libvirt. The libvirt process needs the secret key to access the cluster while attaching a block device from Cinder. Create a temporary copy of the secret key on the OpenStack Nova nodes:

   [root@mon ~]# ceph auth get-key client.cinder | ssh NOVA_NODE tee client.cinder.key

   If the storage cluster contains Ceph block device images that use the exclusive-lock feature, ensure that all Ceph block device users have permissions to blacklist clients:

   [root@mon ~]# ceph auth caps client.ID mon 'allow r, allow command "osd blacklist"' osd 'EXISTING_OSD_USER_CAPS'

5. Return to the OpenStack Nova node:

   [root@mon ~]# ssh NOVA_NODE

6. Generate a UUID for the secret, and save the UUID of the secret for configuring nova-compute later:

   [root@nova ~]# uuidgen > uuid-secret.txt

   Note

   You do not necessarily need the UUID on all the Nova compute nodes. However, from a platform consistency perspective, it’s better to keep the same UUID.

7. On the OpenStack Nova nodes, add the secret key to libvirt and remove the temporary copy of the key:

   cat > secret.xml <<EOF
   <secret ephemeral='no' private='no'>
     <uuid>`cat uuid-secret.txt`</uuid>
     <usage type='ceph'>
       <name>client.cinder secret</name>
     </usage>
   </secret>
   EOF

8. Set and define the secret for libvirt:

   [root@nova ~]# virsh secret-define --file secret.xml
   [root@nova ~]# virsh secret-set-value --secret $(cat uuid-secret.txt) --base64 $(cat client.cinder.key) && rm client.cinder.key secret.xml

Procedure

1. Edit the Cinder configuration file:

   [root@cinder ~]# vim /etc/cinder/cinder.conf

2. In the [DEFAULT] section, enable Ceph as a backend for Cinder:

   enabled_backends = ceph

3. Ensure that the Glance API version is set to 2. If you are configuring multiple cinder back ends in enabled_backends, the glance_api_version = 2 setting must be in the [DEFAULT] section and not the [ceph] section.

   glance_api_version = 2

4. Create a [ceph] section in the cinder.conf file. Add the Ceph settings in the following steps under the [ceph] section.

5. Specify the volume_driver setting and set it to use the Ceph block device driver:

   volume_driver = cinder.volume.drivers.rbd.RBDDriver

6. Specify the cluster name and Ceph configuration file location. In typical deployments the Ceph cluster has a cluster name of ceph and a Ceph configuration file at /etc/ceph/ceph.conf. If the Ceph cluster name is not ceph, specify the cluster name and configuration file path appropriately:

   rbd_cluster_name = us-west
   rbd_ceph_conf = /etc/ceph/us-west.conf

7. By default, Red Hat OpenStack Platform stores Ceph volumes in the rbd pool. To use the volumes pool created earlier, specify the rbd_pool setting and set the volumes pool:

   rbd_pool = volumes

8. Red Hat OpenStack Platform does not have a default user name or a UUID of the secret for volumes. Specify rbd_user and set it to the cinder user. Then, specify the rbd_secret_uuid setting and set it to the generated UUID stored in the uuid-secret.txt file:

   rbd_user = cinder
   rbd_secret_uuid = 4b5fd580-360c-4f8c-abb5-c83bb9a3f964

9. Specify the following settings:

   rbd_flatten_volume_from_snapshot = false
   rbd_max_clone_depth = 5
   rbd_store_chunk_size = 4
   rados_connect_timeout = -1

   When you configure Cinder to use Ceph block devices, the configuration file might look similar to this:

   Example

   [DEFAULT]
   enabled_backends = ceph
   glance_api_version = 2
   …
   
   [ceph]
   volume_driver = cinder.volume.drivers.rbd.RBDDriver
   rbd_cluster_name = ceph
   rbd_pool = volumes
   rbd_user = cinder
   rbd_ceph_conf = /etc/ceph/ceph.conf
   rbd_flatten_volume_from_snapshot = false
   rbd_secret_uuid = 4b5fd580-360c-4f8c-abb5-c83bb9a3f964
   rbd_max_clone_depth = 5
   rbd_store_chunk_size = 4
   rados_connect_timeout = -1

   Note

   Consider removing the default [lvm] section and its settings.

Procedure

1. Edit the Cinder configuration file:

   [root@cinder ~]# vim /etc/cinder/cinder.conf

2. Go to the [ceph] section of the configuration file.

3. Specify the backup_driver setting and set it to the Ceph driver:

   backup_driver = cinder.backup.drivers.ceph

4. Specify the backup_ceph_conf setting and specify the path to the Ceph configuration file:

   backup_ceph_conf = /etc/ceph/ceph.conf

   Note

   The Cinder backup Ceph configuration file may be different from the Ceph configuration file used for Cinder. For example, it can point to a different Ceph storage cluster.

5. Specify the Ceph pool for backups:

   backup_ceph_pool = backups

   Note

   The Ceph configuration file used for Cinder backup might be different from the Ceph configuration file used for Cinder.

6. Specify the backup_ceph_user setting and specify the user as cinder-backup:

   backup_ceph_user = cinder-backup

7. Specify the following settings:

   backup_ceph_chunk_size = 134217728
   backup_ceph_stripe_unit = 0
   backup_ceph_stripe_count = 0
   restore_discard_excess_bytes = true

   When you include the Cinder options, the [ceph] section of the cinder.conf file might look similar to this:

   Example

   [ceph]
   volume_driver = cinder.volume.drivers.rbd.RBDDriver
   rbd_cluster_name = ceph
   rbd_pool = volumes
   rbd_user = cinder
   rbd_ceph_conf = /etc/ceph/ceph.conf
   rbd_flatten_volume_from_snapshot = false
   rbd_secret_uuid = 4b5fd580-360c-4f8c-abb5-c83bb9a3f964
   rbd_max_clone_depth = 5
   rbd_store_chunk_size = 4
   rados_connect_timeout = -1
   
   backup_driver = cinder.backup.drivers.ceph
   backup_ceph_user = cinder-backup
   backup_ceph_conf = /etc/ceph/ceph.conf
   backup_ceph_chunk_size = 134217728
   backup_ceph_pool = backups
   backup_ceph_stripe_unit = 0
   backup_ceph_stripe_count = 0
   restore_discard_excess_bytes = true

8. Verify if Cinder backup is enabled:

   [root@cinder ~]# cat /etc/openstack-dashboard/local_settings | grep enable_backup

   If enable_backup is set to False, then edit the local_settings file and set it to True.

   Example

   OPENSTACK_CINDER_FEATURES = {
       'enable_backup': True,
   }

Procedure

1. To use Ceph block devices by default, edit the /etc/glance/glance-api.conf file. If you used different pool, user or Ceph configuration file settings apply the appropriate values. Uncomment the following settings if necessary and change their values accordingly:

   [root@glance ~]# vim /etc/glance/glance-api.conf

   stores = rbd
   default_store = rbd
   rbd_store_chunk_size = 8
   rbd_store_pool = images
   rbd_store_user = glance
   rbd_store_ceph_conf = /etc/ceph/ceph.conf

2. To enable copy-on-write (CoW) cloning set show_image_direct_url to True.

   show_image_direct_url = True

   Important

   Enabling CoW exposes the back end location via Glance’s API, so the endpoint should not be publicly accessible.

3. Disable cache management if necessary. The flavor should be set to keystone only, not keystone+cachemanagement.

   flavor = keystone

4. Red Hat recommends the following properties for images:

   hw_scsi_model=virtio-scsi
   hw_disk_bus=scsi
   hw_qemu_guest_agent=yes
   os_require_quiesce=yes

   The virtio-scsi controller gets better performance and provides support for discard operations. For systems using SCSI/SAS drives, connect every Cinder block device to that controller. Also, enable the QEMU guest agent and send fs-freeze/thaw calls through the QEMU guest agent.

Procedure

1. Edit the Ceph configuration file:

   [root@nova ~]# vim /etc/ceph/ceph.conf

2. Add the following section to the [client] section of the Ceph configuration file:

   [client]
   rbd cache = true
   rbd cache writethrough until flush = true
   rbd concurrent management ops = 20
   admin socket = /var/run/ceph/guests/$cluster-$type.$id.$pid.$cctid.asok
   log file = /var/log/ceph/qemu-guest-$pid.log

3. Create new directories for the admin socket and log file, and change the directory permissions to use the qemu user and libvirtd group:

   [root@nova ~]# mkdir -p /var/run/ceph/guests/ /var/log/ceph/
   [root@nova ~]# chown qemu:libvirt /var/run/ceph/guests /var/log/ceph/

   Note

   The directories must be allowed by SELinux or AppArmor.

4. On each Nova node, edit the /etc/nova/nova.conf file. Under the [libvirt] section, configure the following settings:

   Example

   [libvirt]
   images_type = rbd
   images_rbd_pool = vms
   images_rbd_ceph_conf = /etc/ceph/ceph.conf
   rbd_user = cinder
   rbd_secret_uuid = 4b5fd580-360c-4f8c-abb5-c83bb9a3f964
   disk_cachemodes="network=writeback"
   inject_password = false
   inject_key = false
   inject_partition = -2
   live_migration_flag="VIR_MIGRATE_UNDEFINE_SOURCE,VIR_MIGRATE_PEER2PEER,VIR_MIGRATE_LIVE,VIR_MIGRATE_PERSIST_DEST,VIR_MIGRATE_TUNNELLED"
   hw_disk_discard = unmap

   Replace the UUID in rbd_user_secret with the UUID in the uuid-secret.txt file.

Procedure

1. Load the block device pool names and Ceph user names into the configuration file.

2. Restart the appropriate OpenStack services after modifying the corresponding configuration files:

   [root@osp ~]# systemctl restart openstack-cinder-volume
   [root@osp ~]# systemctl restart openstack-cinder-backup
   [root@osp ~]# systemctl restart openstack-glance-api
   [root@osp ~]# systemctl restart openstack-nova-compute