.. _external-ceph-guide: ============= External Ceph ============= Sometimes it is necessary to connect OpenStack services to an existing Ceph cluster instead of deploying it with Kolla. This can be achieved with only a few configuration steps in Kolla. Requirements ============ * An existing installation of Ceph * Existing Ceph storage pools * Existing credentials in Ceph for OpenStack services to connect to Ceph (Glance, Cinder, Nova) Enabling External Ceph ====================== Using external Ceph with Kolla means not to deploy Ceph via Kolla. Therefore, disable Ceph deployment in ``/etc/kolla/global.yml`` :: enable_ceph: "no" There are flags indicating individual services to use ceph or not which default to the value of ``enable_ceph``. Those flags now need to be activated in order to activate external Ceph integration. This can be done individually per service in ``/etc/kolla/global.yml``: :: glance_backend_ceph: "yes" cinder_backend_ceph: "yes" The combination of ``enable_ceph: "no"`` and ``_backend_ceph: "yes"`` triggers the activation of external ceph mechanism in Kolla. Configuring External Ceph ========================= Glance ------ Configuring Glance for Ceph includes three steps: 1) Configure RBD backend in glance-api.conf 2) Create Ceph configuration file in /etc/ceph/ceph.conf 3) Create Ceph keyring file in /etc/ceph/ceph.client..keyring Step 1 is done by using Kolla's INI merge mechanism: Create a file in ``/etc/kolla/config/glance/glance-api.conf`` with the following contents: :: [DEFAULT] show_image_direct_url = True [glance_store] stores = rbd default_store = rbd rbd_store_pool = images rbd_store_user = glance rbd_store_ceph_conf = /etc/ceph/ceph.conf [image_format] container_formats = bare disk_formats = raw Now put ceph.conf and the keyring file (name depends on the username created in Ceph) into the same directory, for example: /etc/kolla/config/glance/ceph.conf :: [global] fsid = 1d89fec3-325a-4963-a950-c4afedd37fe3 mon_initial_members = ceph-0 mon_host = 192.168.0.56 auth_cluster_required = cephx auth_service_required = cephx auth_client_required = cephx /etc/kolla/config/glance/ceph.client.glance.keyring :: [client.glance] key = AQAg5YRXS0qxLRAAXe6a4R1a15AoRx7ft80DhA== Kolla will pick up all files named ceph.* in this directory an copy them to the /etc/ceph/ directory of the container. Cinder ------ Configuring external Ceph for Cinder works very similar to Glance. The required Cinder configuration goes into /etc/kolla/config/cinder/cinder-volume.conf: :: [DEFAULT] enabled_backends=rbd-1 [rbd-1] rbd_ceph_conf=/etc/ceph/ceph.conf rbd_user=cinder backend_host=rbd:volumes rbd_pool=volumes volume_backend_name=rbd-1 volume_driver=cinder.volume.drivers.rbd.RBDDriver Next, place the ceph.conf file into /etc/kolla/config/cinder/ceph.conf: :: [global] fsid = 1d89fec3-325a-4963-a950-c4afedd37fe3 mon_initial_members = ceph-0 mon_host = 192.168.0.56 auth_cluster_required = cephx auth_service_required = cephx auth_client_required = cephx Separate configuration options can be configured for cinder-volume and cinder-backup by adding ceph.conf files to /etc/kolla/config/cinder/cinder-volume and /etc/kolla/config/cinder/cinder-backup respectively. They will be merged with /etc/kolla/config/cinder/ceph.conf. Ceph keyrings are deployed per service and placed into cinder-volume and cinder-backup directories: :: root@deploy:/etc/kolla/config# cat cinder/cinder-backup/ceph.client.cinder.keyring [client.cinder] key = AQAg5YRXpChaGRAAlTSCleesthCRmCYrfQVX1w== root@deploy:/etc/kolla/config# cat cinder/cinder-volume/ceph.client.cinder.keyring [client.cinder] key = AQAg5YRXpChaGRAAlTSCleesthCRmCYrfQVX1w== It is important that the files are named ceph.client*. Nova ------ In ``/etc/kolla/global.yml`` set :: nova_backend_ceph: "yes" Put ceph.conf and keyring file into ``/etc/kolla/config/nova``: :: $ ls /etc/kolla/config/nova ceph.client.nova.keyring ceph.conf Configure nova-compute to use Ceph as the ephemeral backend by creating ``/etc/kolla/config/nova/nova-compute.conf`` and adding the following contents: :: [libvirt] images_rbd_pool=vms images_type=rbd images_rbd_ceph_conf=/etc/ceph/ceph.conf rbd_user=nova NOTE: rbd_user might vary depending on your environment.