openstack/manila
Code Issues Proposed changes
c36c8a5e62
manila/doc/source/configuration/shared-file-systems/drivers/zfs-on-linux-driver.rst
Tom Barron fae499cb73 doc migration: configuration reference 
In accord with the OpenStack documentation migration spec [1],
this patch pulls over material from the centralized Configuration
Reference so that it will not be lost.  As indicated in the spec,
dynamic generation of this material will be left for later work.

[1] https://specs.openstack.org/openstack/docs-specs/specs/pike/os-manuals-migration.html

Closes-Bug: #1706181
Depends-On: Ib0fca0c16e14c05307bfc31ae50c65271b7402f1
Depends-On: Ia750cb049c0f53a234ea70ce1f2bbbb7a2aa9454

Change-Id: I7f3b584ac9907da1f07dedd26324cf4703bc7e6c
2017-08-25 13:21:08 +00:00

4.9 KiB
Raw Blame History

ZFS (on Linux) driver

Manila ZFSonLinux share driver uses ZFS file system for exporting NFS shares. Written and tested using Linux version of ZFS.

Requirements

  • NFS daemon that can be handled through exportfs app.
  • ZFS file system packages, either Kernel or FUSE versions.
  • ZFS zpools that are going to be used by Manila should exist and be configured as desired. Manila will not change zpool configuration.
  • For remote ZFS hosts according to manila-share service host SSH should be installed.
  • For ZFS hosts that support replication:
    • SSH access for each other should be passwordless.
    • Service IP addresses should be available by ZFS hosts for each other.

Supported shared filesystems and operations

The driver supports NFS shares.

The following operations are supported:

  • Create a share.
  • Delete a share.
  • Allow share access.
    • Only IP access type is supported.
    • Both access levels are supported - RW and RO.
  • Deny share access.
  • Create a snapshot.
  • Delete a snapshot.
  • Create a share from snapshot.
  • Extend a share.
  • Shrink a share.
  • Share replication (experimental):
    • Create, update, delete, and promote replica operations are supported.

Possibilities

  • Any amount of ZFS zpools can be used by share driver.
  • Allowed to configure default options for ZFS datasets that are used for share creation.
  • Any amount of nested datasets is allowed to be used.
  • All share replicas are read-only, only active one is read-write.
  • All share replicas are synchronized periodically, not continuously. Status in_sync means latest sync was successful. Time range between syncs equals to the value of the replica_state_update_interval configuration global option.
  • Driver can use qualified extra spec zfsonlinux:compression. It can contain any value that ZFS app supports. But if it is disabled through the configuration option with the value compression=off, then it will not be used.

Restrictions

The ZFSonLinux share driver has the following restrictions:

  • Only IP access type is supported for NFS.
  • Only FLAT network is supported.
  • Promote share replica operation will switch roles of current secondary replica and active. It does not make more than one active replica available.
  • The below items are not yet implemented:
    • Manage share operation.
    • Manage snapshot operation.
    • SaMBa based sharing.
    • Thick provisioning capability.

Known problems

  • Promote share replica operation will make ZFS file system that became secondary as RO only on NFS level. On ZFS level system will stay mounted as was - RW.

Back-end configuration

The following parameters need to be configured in the manila configuration file for back-ends that use the ZFSonLinux driver:

  • share_driver = manila.share.drivers.zfsonlinux.driver.ZFSonLinuxShareDriver
  • driver_handles_share_servers = False
  • replication_domain = custom_str_value_as_domain_name
    • If empty, then replication will be disabled.
    • If set, then will be able to be used as replication peer for other back ends with the same value.
  • zfs_share_export_ip = <user_facing IP address of ZFS host>
  • zfs_service_ip = <IP address of service network interface of ZFS host>
  • zfs_zpool_list = zpoolname1,zpoolname2/nested_dataset_for_zpool2
    • Can be one or more zpools.
    • Can contain nested datasets.
  • zfs_dataset_creation_options = <list of ZFS dataset options>
    • readonly, quota, sharenfs and sharesmb options will be ignored.
  • zfs_dataset_name_prefix = <prefix>
    • Prefix to be used in each dataset name.
  • zfs_dataset_snapshot_name_prefix = <prefix>
    • Prefix to be used in each dataset snapshot name.
  • zfs_use_ssh = <boolean_value>
    • Set False if ZFS located on the same host as manila-share service.
    • Set True if manila-share service should use SSH for ZFS configuration.
  • zfs_ssh_username = <ssh_username>
    • Required for replication operations.
    • Required for SSHing to ZFS host ifzfs_use_sshis set toTrue``.
  • zfs_ssh_user_password = <ssh_user_password>
    • Password for zfs_ssh_username of ZFS host.
    • Used only if zfs_use_ssh is set to True.
  • zfs_ssh_private_key_path = <path_to_private_ssh_key>
    • Used only if zfs_use_ssh is set to True.
  • zfs_share_helpers = NFS=manila.share.drivers.zfsonlinux.utils.NFSviaZFSHelper
    • Approach for setting up helpers is similar to various other share drivers.
    • At least one helper should be used.
  • zfs_replica_snapshot_prefix = <prefix>
    • Prefix to be used in dataset snapshot names that are created by update replica operation.

Driver options