Daniel P. Berrange wrote:
On Mon, Jan 27, 2014 at 06:39:36PM -0700, Jim Fehlig wrote:
[Adding libvirt list...]
Ian Jackson wrote:
Jim Fehlig writes ("Re: [Xen-devel] [PATCH 00/12] libxl: fork: SIGCHLD flexibility"):
BTW, I meant to ask before - what is the SIGCHLD reference about in the subject line ?
This is related to child processes started by libxl. E.g. running a bootloader when creating PV VMs, running a save/restore helper when saving/restoring a VM, etc.
libvirt drivers that live inside libvirtd should never use or rely on the SIGCHLD signal at all. All VM processes started by libvirtd ought to be fully daemonized so that their parent is pid 1 / init. This ensures that the libvirtd daemon can be restarted without all the VMs getting reaped. Once the VMs are reparented to init, then libvirt or library code it uses has no way of ever receiving SIGCHLD.
Nod. VMs are "daemonized", in the context of Xen. Once running, libvirtd can be restarted without reaping them. Regards, Jim