Support iSER driver within the ISCSIDriver flow

Support iSER driver within the ISCSIDriver flow

https://blueprints.launchpad.net/cinder/+spec/support-iscsi-driver

This purpose of this BP is to avoid code duplications of classes and parameters, and to prevent instability in the iSER driver flow, for the TGT and LIO cases.

Problem description

  1. Currently the iSER driver is supported over TGT only, without LIO support.
  2. There are a couple of iSER classes that inherit from iSCSI driver/target classes, but most of their functionality is the same as the iSCSI classes. This code duplication causes instability in the iSER driver code, when new features or changes are added to the iSCSI driver flow.

Use Cases

Proposed change

These two problems can be solved by adding a small fix, which includes a new enable_iser parameter within iSCSI Tgt/LIO classes.

All that is needed for RDMA support over iSER, in the Tgt and LIO cases, is to set just one extra parameter in the volume creation stage.

A deprecation alert will be added to ISERTgtAdm, since This change will act as a replacement to the current iSER Tgt code.

The Nova part of this spec is specified at: https://review.openstack.org/#/c/130721/

Alternatives

Leaving ISERTgtAdm, LVMISERDriver, ISERDriver and iser_opts the way they are, or just deprecating a part of them (but it will miss the purpose of this code refactoring).

Data model impact

None

REST API impact

None

Security impact

None

Notifications impact

None

Other end user impact

None

Performance Impact

None

Other deployer impact

Adding a new “enable_iser” parameter, set to “False” by default. This parameter will be used in TGT or LIO volume creation for setting RDMA based portals.

This single parameter will deprecate all iser_opts parameters, that are a duplication from iscsi parameters.

Developer impact

This change will simplify the maintanance of the iSER driver flow, since no extra classes or duplicated parameters will be used.

Implementation

Assignee(s)

Aviram Bar-Haim <aviramb@mellanox.com>

Work Items

  1. Fix bug https://bugs.launchpad.net/cinder/+bug/1396265 and add the correct driver parameter, with a configurable value to VOLUME_CONF and VOLUME_CONF_WITH_CHAP_AUTH.
  2. Add a new “enable_iser” parameter that is set to false by default.
  3. Set the driver parameter at the VOLUME_CONFs template in TgtAdm for the TGT case.
  4. Add _set_iser(1) on the network portal object in rtslib for the LIO case, according to “enable_iser” value.
  5. Set ISCSIDriver’s “driver_volume_type” to “iscsi” or “iser” value, according to the “enable_iser” value.

Dependencies

None

Testing

HW that supports RDMA is required in order to test volume attachment over iSER.

A new unit test will be added with the new enable_iser parameter over iSCSI volume driver.

Documentation Impact

After adding the new enable_iser parameter, An updated iSER configuration guidelines will be added to:

References

None

Creative Commons Attribution 3.0 License

Except where otherwise noted, this document is licensed under Creative Commons Attribution 3.0 License. See all OpenStack Legal Documents.

cinder-specs 0.0.1.dev432