Comment 3 for bug 1732199

With more recent logs, here is where c-vol POSTS the volume-extended event to nova:

http://logs.openstack.org/69/595069/2/gate/tempest-full/169db43/controller/logs/screen-c-vol.txt.gz#_Sep_24_10_55_25_282139

Sep 24 10:55:25.282139 ubuntu-xenial-rax-ord-0002235107 cinder-volume[17004]: DEBUG novaclient.v2.client [None req-eb1112fc-2010-4878-b6ed-7bd6d5c65b82 tempest-VolumesExtendAttachedTest-1848768 None] REQ: curl -g -i --cacert "/opt/stack/data/ca-bundle.pem" -X POST https://10.210.68.187/compute/v2.1/os-server-external-events -H "Accept: application/json" -H "Content-Type: application/json" -H "OpenStack-API-Version: compute 2.51" -H "User-Agent: python-novaclient" -H "X-Auth-Token: {SHA256}923f610d5ad7db48532294c1bb9afa3f9696c80c054fdaf0e20fea7e6f695ef0" -H "X-OpenStack-Nova-API-Version: 2.51" -H "X-OpenStack-Request-ID: req-eb1112fc-2010-4878-b6ed-7bd6d5c65b82" -d '{"events": [{"tag": "26727af1-a60f-4753-baf5-7e7012361915", "name": "volume-extended", "server_uuid": "6360ef8e-bda1-4775-86db-cfc19255d4f2"}]}' {{(pid=17123) _http_log_request /usr/local/lib/python2.7/dist-packages/keystoneauth1/session.py:448}}

And then we fail on the nova-compute side:

http://logs.openstack.org/69/595069/2/gate/tempest-full/169db43/controller/logs/screen-n-cpu.txt.gz#_Sep_24_10_55_26_759691

Sep 24 10:55:26.759691 ubuntu-xenial-rax-ord-0002235107 nova-compute[15157]: WARNING os_brick.initiator.connectors.iscsi [req-eb1112fc-2010-4878-b6ed-7bd6d5c65b82 req-118f3f55-90c0-47b4-98c9-9b8069625dce service nova] Couldn't find iscsi sessions because iscsiadm err: iscsiadm: could not read session targetname: 5
Sep 24 10:55:26.760040 ubuntu-xenial-rax-ord-0002235107 nova-compute[15157]: iscsiadm: could not find session info for session22
Sep 24 10:55:26.760399 ubuntu-xenial-rax-ord-0002235107 nova-compute[15157]:
Sep 24 10:55:26.760774 ubuntu-xenial-rax-ord-0002235107 nova-compute[15157]: INFO os_brick.initiator.connectors.iscsi [req-eb1112fc-2010-4878-b6ed-7bd6d5c65b82 req-118f3f55-90c0-47b4-98c9-9b8069625dce service nova] Found paths for volume []

Is this transient? Should nova-compute or os-brick add a retry loop if the volume paths aren't found during extend?