nbdclient fails to connect

[bjo81]

Dec 23 00:57:59 host.domain.org s3backer[44815]: s3backer: connecting nbdcloud to /dev/nbd0 and daemonizing
Dec 23 00:57:59 host.domain.org nbdkit[44952]: s3backer: starting non-zero block survey
Dec 23 00:57:59 host.domain.org systemd[1]: Started s3backer running in NBD mode.
Dec 23 00:57:59 host.domain.org nbdkit[44952]: s3backer: mounting nbdcloud
Dec 23 00:58:00 host.domain.org nbd_client[44961]: Read failed: Connection reset by peer
Dec 23 00:58:00 host.domain.org nbd_client[44961]: Exiting.
Dec 23 00:58:00 host.domain.org nbd_client[44961]: INIT_PASSWD bad
Dec 23 00:58:00 host.domain.org nbd_client[44961]: Exiting.

s3-backer 2.1.1
nbd-client 3.25

[archiecobbs]

Hmm. This looks like a some kind of kernel/NBD problem not specific to s3backer.

E.g., see this thread).

Unfortunately my familiarity with the inner guts of NBD is minimal.

[bjo81]

Confusingly it works with nbd-client 3.20. Could it be related to nbdkit?

[archiecobbs]

Confusingly it works with nbd-client 3.20. Could it be related to nbdkit?

Definitely - it could be that there is a bug in newer nbd, or (more likely) something s3backer is doing is incompatible with newer nbd, or ...?

When you say "works with" another version of nbd, are you completely recompiling s3backer using the proper version of nbdkit-devel?

In other words, it's possible there is some mismatch between the version of nbdkit s3backer is compiled with and/or the installed versions of nbd and/or nbd-client, etc.

[bjo81]

No, I only downgraded nbd from 3.25 to 3.20, nbdkit and was not recompiled.