RemoteFS Config Improvements

https://blueprints.launchpad.net/cinder/+spec/remotefs-share-cfg-improvements

RemoteFS drivers (NFS, GlusterFS, etc.) are currently configured by adding a list of shares to a text config file which is referenced by cinder.conf. This means that one driver instance manages a handful of storage locations for the driver. This work will a) have these drivers configured like most other Cinder drivers are, and b) leverage the Cinder scheduler for selection between different storage backends rather than having the driver act as a pseudo-scheduler.

Problem description

The configuration system for NFS/GlusterFS/etc drivers:

  • is different from other drivers

  • is more complex than necessary

  • limits functionality such as migration

Use Cases

Proposed change

Replace the <x>_shares_config setting with settings that can be used to login to the storage platforms. This means that an nfs_shares_config file such as:

192.168.1.10:/export1 -o sync
192.168.1.11:/export2 -o vers=nfs4

would become, in cinder.conf:

[nfs1]
address = 192.168.1.10
export_path = /export1
options = -o sync

[nfs2]
address = 192.168.1.11
export_path = /export2
options = -o vers=nfs4

Each Cinder backend will then only manage one export rather than a handful of exports. This brings the RemoteFS drivers closer to how other Cinder drivers operate.

Alternatives

Leave things as they are today. (Not desirable.)

Data model impact

None

REST API impact

None

Security impact

None

Notifications impact

None

Other end user impact

It will be possible to use Cinder volume migration to move volumes between all NFS exports when previously this was not always possible (since the different exports were managed by the same driver instance).

Performance Impact

None

Other deployer impact

nfs_shares_config, glusterfs_shares_config, etc., will be deprecated (but still functional for Kilo). Setting the new options will cause these settings to be ignored.

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

eharney

Other contributors:

Other interested parties?

Work Items

  • Create new options for address, export, mount options

  • Mark options and code to be removed in L as deprecated in Kilo

Dependencies

None

Testing

The NFS driver and GlusterFS drivers will be gaining CI during the Kilo cycle which will cover this.

Manual testing should cover both the current and new configuration paths.

Documentation Impact

New configuration options and possibly guide changes for configuring the NFS driver.

References

None