cinder increases the variety of multipath tool support, such as zte superpath etc
when attach the volume to host before copy image to volume, we can use multipath device. Currently only support "multipath" tool to manage iSCSI volume.
Different storage equipment manufacturers will generally provide matching of Multipath tools, such as EMC powerpath, Fujitsu ETERNUS Multipath Driver, zte superpath etc, in order to realize the personalized features.
This blueprint is designed to support multiple multipath tools, adopts the factory class, base class defines a method, each multipath tool to create a subclass, subclass implementation concrete method. Every increase a multipath tool, a new subclass, has the very good extensibility.
Increase iscsi_used_
Late early support multipath and superpath, according to the need to expand.