Description of problem:

When engine start the NBD server in vdsm during upload (e.g. restore) or
download (e.g. offline backup) it uses the image transfer ticket id as the
server id. This id is used to create a socket at /run/vdsm/nbd/{id} and for
stopping the server.

We have 2 UUIDs for an image tranfer:
- The transfer id - used as the engine command id.
- The ticket id - used for authenticating the client with imageio server.

The ticket id is sensitive information that should not be logged while the
transfer is active. The transfer id is public information that may be logged
everywhere, and we want all events related to image transfer to have this id.

Here are example logs in vdsm that should use the transfer id instead of the
ticket id:

# grep e285c666-fde0-431b-a993-36315d651e42 /var/log/vdsm/vdsm.log

2022-01-21 00:53:06,843+0200 INFO  (jsonrpc/4) [vdsm.api] START start_nbd_server(server_id='e285c666-fde0-431b-a993-36315d651e42', config={'detect_zeroes': True, 'discard': False, 'readonly': True, 'bitmap': None, 'sd_id': 'aecec81f-d464-4a35-9a91-6acf2ca4938c', 'img_id': '69015aa7-b4c5-4bd7-b1d3-c183494975e0', 'vol_id': '37ca5b02-e993-4cfe-b337-1f5f4b70a883', 'backing_chain': True}) from=::ffff:192.168.122.10,58050, flow_id=5b7bb8a1-632f-47a5-a29b-d6966a1943fd, task_id=28c288d3-b4c6-4bcf-ad1a-ecef08aebc4c (api:48)

2022-01-21 00:53:06,856+0200 INFO  (jsonrpc/4) [storage.nbd] Starting transient service vdsm-nbd-e285c666-fde0-431b-a993-36315d651e42.service, serving /rhev/data-center/mnt/blockSD/aecec81f-d464-4a35-9a91-6acf2ca4938c/images/69015aa7-b4c5-4bd7-b1d3-c183494975e0/37ca5b02-e993-4cfe-b337-1f5f4b70a883 via unix socket /run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock (nbd:142)

2022-01-21 00:53:06,892+0200 INFO  (jsonrpc/4) [vdsm.api] FINISH start_nbd_server return={'result': 'nbd:unix:/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock'} from=::ffff:192.168.122.10,58050, flow_id=5b7bb8a1-632f-47a5-a29b-d6966a1943fd, task_id=28c288d3-b4c6-4bcf-ad1a-ecef08aebc4c (api:54)

2022-01-21 00:53:13,059+0200 INFO  (jsonrpc/6) [vdsm.api] START stop_nbd_server(server_id='e285c666-fde0-431b-a993-36315d651e42') from=::ffff:192.168.122.10,58050, flow_id=5b7bb8a1-632f-47a5-a29b-d6966a1943fd, task_id=47a33712-39aa-4015-a604-553d8549db86 (api:48)
2022-01-21 00:53:13,073+0200 INFO  (jsonrpc/6) [storage.nbd] Stopping transient service vdsm-nbd-e285c666-fde0-431b-a993-36315d651e42.service (nbd:184)


Here are example logs in imageio that should use the transfer id instead of the ticket id:

# grep e285c666-fde0-431b-a993-36315d651e42 /var/log/ovirt-imageio/daemon.log

2022-01-21 00:53:07,988 INFO    (Thread-11) [images] [::ffff:192.168.122.1] OPTIONS ticket=e285c666-fde0-431b-a993-36315d651e42

2022-01-21 00:53:07,988 INFO    (Thread-11) [backends.nbd] Open backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock' export_name='' sparse=False max_connections=8

2022-01-21 00:53:07,989 INFO    (Thread-11) [extents] [::ffff:192.168.122.1] EXTENTS ticket=e285c666-fde0-431b-a993-36315d651e42 context=zero

2022-01-21 00:53:08,043 INFO    (Thread-12) [backends.nbd] Open backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock' export_name='' sparse=False max_connections=8

2022-01-21 00:53:08,047 INFO    (Thread-13) [backends.nbd] Open backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock' export_name='' sparse=False max_connections=8

2022-01-21 00:53:08,050 INFO    (Thread-14) [backends.nbd] Open backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock' export_name='' sparse=False max_connections=8

2022-01-21 00:53:08,052 INFO    (Thread-15) [backends.nbd] Open backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock' export_name='' sparse=False max_connections=8

2022-01-21 00:53:10,519 INFO    (Thread-13) [backends.nbd] Close backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock'

2022-01-21 00:53:10,552 INFO    (Thread-15) [backends.nbd] Close backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock'

2022-01-21 00:53:10,569 INFO    (Thread-12) [backends.nbd] Close backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock'

2022-01-21 00:53:10,672 INFO    (Thread-14) [backends.nbd] Close backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock'

2022-01-21 00:53:10,674 INFO    (Thread-11) [backends.nbd] Close backend address='/run/vdsm/nbd/e285c666-fde0-431b-a993-36315d651e42.sock'


Fixing all these logs is very easy - when engine starts the nbd server,
it should use the transfer id instead of the ticket id. 


Version-Release number of selected component (if applicable):
Any

How reproducible:
Always

Steps to Reproduce:
1. Perform upload or download using the example sdk scripts
2. Grep vdsm and imageio logs with the ticket id

Actual results:
Ticket id used for nbd server id and socket

Expected results:
Should use the transfer id

This should be trivial change in engine, vdsm and imageio do not need to change.