[Libguestfs] [libguestfs/nbdkit] nbdkit server hangs during negotiation when running in background, works in foreground (Issue #16)

[Richard W.M. Jones]

On Sun, Oct 24, 2021 at 01:07:19AM -0700, Nathan Shearer wrote:
> With my current setup, the issue is reproducible. If I start the
> nbdkit server by placing a startup script in /etc/local.d to start
> on boot, it will start, but the nbd-client will always hang during
> negotiation. Killing and restarting the server and/or the client
> does not resolve the deadlock.
>
> However, if I run the exact same script manually, by logging into
> the server, then nbd-client is able to successfully connect to the
> nbdkit server and everything works as expected.
>
> During my tests, I found that when I killed nbdkit, it would see
> errors about their being insufficient "magic" or an invalid
> password. I am not using any passwords, and both the nbdkit server
> and nbd-client are on the same host, connecting through 127.0.0.1

I'm a bit unclear - how does it hang?  What happens if you enable
verbose messages (-v), what messages are sent to the log?

Also try connecting with

  LIBNBD_DEBUG=1 nbdinfo nbd://server

and see where it hangs in negotiation.

Rich.

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