CephFS Native driver¶
The CephFS Native driver enables the Shared File Systems service to export shared file systems to guests using the Ceph network protocol. Guests require a Ceph client in order to mount the file system.
Access is controlled via Ceph’s cephx authentication system. When a user requests share access for an ID, Ceph creates a corresponding Ceph auth ID and a secret key, if they do not already exist, and authorizes the ID to access the share. The client can then mount the share using the ID and the secret key.
To learn more about configuring Ceph clients to access the shares created using this driver, please see the Ceph documentation ( http://docs.ceph.com/docs/master/cephfs/). If you choose to use the kernel client rather than the FUSE client, the share size limits set in the Shared File Systems service may not be obeyed.
Requirements¶
Mitaka or later versions of manila.
Jewel or later versions of Ceph.
A Ceph cluster with a file system configured ( http://docs.ceph.com/docs/master/cephfs/createfs/)
ceph-commonpackage installed in the servers running themanila-shareservice.Ceph client installed in the guest, preferably the FUSE based client,
ceph-fuse.Network connectivity between your Ceph cluster’s public network and the servers running the
manila-shareservice.Network connectivity between your Ceph cluster’s public network and guests.
Important
A manila share backed onto CephFS is only as good as the underlying file system. Take care when configuring your Ceph cluster, and consult the latest guidance on the use of CephFS in the Ceph documentation ( http://docs.ceph.com/docs/master/cephfs/).
Authorize the driver to communicate with Ceph¶
Run the following commands to create a Ceph identity for the Shared File Systems service to use:
read -d '' MON_CAPS << EOF
allow r,
allow command "auth del",
allow command "auth caps",
allow command "auth get",
allow command "auth get-or-create"
EOF
ceph auth get-or-create client.manila -o manila.keyring \
mds 'allow *' \
osd 'allow rw' \
mgr 'allow r' \
mon "$MON_CAPS"
manila.keyring, along with your ceph.conf file, then needs to be placed
on the server running the manila-share service.
Enable snapshots in Ceph if you want to use them in the Shared File Systems service:
ceph mds set allow_new_snaps true --yes-i-really-mean-it
In the server running the manila-share service, you can place the
ceph.conf and manila.keyring files in the /etc/ceph directory. Set
the same owner for the manila-share process and the manila.keyring
file. Add the following section to the ceph.conf file.
[client.manila]
client mount uid = 0
client mount gid = 0
log file = /opt/stack/logs/ceph-client.manila.log
admin socket = /opt/stack/status/stack/ceph-$name.$pid.asok
keyring = /etc/ceph/manila.keyring
It is advisable to modify the Ceph client’s admin socket file and log file locations so that they are co-located with the Shared File Systems services’ pid files and log files respectively.
Configure CephFS back end in manila.conf¶
Add CephFS to
enabled_share_protocols(enforced at the Shared File Systems service’s API layer). In this example we leave NFS and CIFS enabled, although you can remove these if you only use CephFS:enabled_share_protocols = NFS,CIFS,CEPHFS
Refer to the following table for the list of all the
cephfs_nativedriver-specific configuration options.Description of CephFS share driver configuration options¶ Configuration option = Default value
Description
[DEFAULT]
cephfs_auth_id=manila(String) The name of the ceph auth identity to use.
cephfs_cluster_name=None(String) The name of the cluster in use, if it is not the default (‘ceph’).
cephfs_conf_path=(String) Fully qualified path to the ceph.conf file.
Create a section to define a CephFS back end:
[cephfs1] driver_handles_share_servers = False share_backend_name = CEPHFS1 share_driver = manila.share.drivers.cephfs.cephfs_native.CephFSNativeDriver cephfs_conf_path = /etc/ceph/ceph.conf cephfs_auth_id = manila cephfs_cluster_name = ceph
Also set the
driver-handles-share-serverstoFalseas the driver does not manage the lifecycle ofshare-servers.Edit
enabled_share_backendsto point to the driver’s back-end section using the section name. In this example we are also including another back end (generic1), you would include whatever other back ends you have configured.enabled_share_backends = generic1,cephfs1
Known restrictions¶
Consider the driver as a building block for supporting multi-tenant workloads in the future. However, it can be used in private cloud deployments.
The guests have direct access to Ceph’s public network.
Snapshots are read-only. A user can read a snapshot’s contents from the
.snap/{manila-snapshot-id}_{unknown-id}folder within the mounted share.To restrict share sizes, CephFS uses quotas that are enforced in the client side. The CephFS clients are relied on to respect quotas.
Security¶
Each share’s data is mapped to a distinct Ceph RADOS namespace. A guest is restricted to access only that particular RADOS namespace.
An additional level of resource isolation can be provided by mapping a share’s contents to a separate RADOS pool. This layout would be preferred only for cloud deployments with a limited number of shares needing strong resource separation. You can do this by setting a share type specification,
cephfs:data_isolatedfor the share type used by the cephfs driver.manila type-key cephfstype set cephfs:data_isolated=TrueUntrusted manila guests pose security risks to the Ceph storage cluster as they would have direct access to the cluster’s public network.
