Cinder Pure Storage logs in only one session when multipath enabled on machine

[Camille Rodriguez]

The cinder-purestorage charm only triggers a single iscsi session to the iscsi backend, even when multipath is enabled on the machine. This is problematic because it ignores the redundancy of the multipath configuration, and the storage blades send alerts that the paths are not redundant.

Setup :
Nova-compute installed on a machine with open-iscsi, iscsid and multipath installed. cinder-volume with only the volume service enable, with cinder-purestorage as subordinate, is also deployed on the same unit as nova-compute.

Before that any VM is created, there is no iscsiadm session detected on the units. A iscsiadm discovery sees 4 possible targets. A login action against the target:port is denied (auth denied).

When a VM is created on the compute, cinder-purestorage creates ONE iscsi session is created towards the iscsi backend. This triggers an alert in the storage backend that only one path is enabled.

After the VM creation, I can manually ssh in the nova-compute unit, run a iscsiadm discovery and iscsiadm login, and only then the 4 sessions are able to login successfully, clearing the alarms seen in the storage backend about multipath.

This manual process (possible only AFTER that the luns are created) is untenable - cinder-purestorage should handle multipath and enable multiple sessions when multipath is configured.

[Camille Rodriguez (camille.rodriguez)]

Subscribed Field Medium as this issue is currently affecting a customer.