Re: [Libguestfs] [libguestfs/nbdkit] nbdkit server hangs during negotiation when running in background, works in foreground (Issue #16)
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. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top
On Sun, Oct 24, 2021 at 11:14:11AM +0100, Richard W.M. Jones wrote:
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.
Also what version of nbdkit? What's in the startup script? Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-p2v converts physical machines to virtual machines. Boot with a live CD or over the network (PXE) and turn machines into KVM guests. http://libguestfs.org/virt-v2v
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Richard W.M. Jones