Comment 10 for bug 1727138

Hi,
I wonder about the "Resource temporarily unavailable" error in this.
This could be something consuming all FDs, or multiple libvirts daemons starting.

What does "ps axlf | grep libvirtd" show you?

Does /var/run/libvirtd.pid exist and if so what is in there.
If it is a pid, which process is that?

[1] had a similar case.

For the issue you see with the 4.10 kernel hat is actually a xen library (not libvirt).
libxl_fork.c:353 is from source:xen ./tools/libxl/libxl_fork.c

341 static void sigchld_installhandler_core(void) /* idempotent */
342 {
343 if (sigchld_installed)
344 return;
345
346 sigchld_installed = 1;
347
348 sigchld_sethandler_raw(sigchld_handler, &sigchld_saved_action);
349
350 assert(((void)"application must negotiate with libxl about SIGCHLD",
351 !(sigchld_saved_action.sa_flags & SA_SIGINFO) &&
352 (sigchld_saved_action.sa_handler == SIG_DFL ||
353 sigchld_saved_action.sa_handler == SIG_IGN)));
354 }

Are you driving xen with your libvirt, or is this just the basic initialization code?

IMHO that is a known upstream issue:
https://www.redhat.com/archives/libvir-list/2015-January/msg00868.html
https://www.redhat.com/archives/libvir-list/2015-November/msg00336.html
https://bugzilla.redhat.com/show_bug.cgi?id=1278847

Due to Xen + vbox + libvirt not playing together nicely.

I don't know what guests you really drive, but as a last resort workaround until one day there is an upstream fix you might disable what you don't use, which means either:
- do not use a xen kernel
- remove one of /usr/lib/libvirt/connection-driver/libvirt_driver_xen.so /usr/lib/libvirt/connection-driver/libvirt_driver_vbox.so (or both if you need none)
  They initialize when they see something they could handle, maybe there is a config to avoid loading them but I don't know (the same search distance away as you)

[1]: https://www.redhat.com/archives/libvirt-users/2012-October/msg00146.html