Re: [libvirt] [PATCH v2] qemu: add a max_core setting to qemu.conf for core dump size

On Tue, Jul 12, 2016 at 12:53:18PM +0200, Martin Kletzander wrote: > On Tue, Jul 12, 2016 at 10:56:53AM +0100, Daniel P. Berrange wrote: > > On Tue, Jul 12, 2016 at 11:38:22AM +0200, Martin Kletzander wrote: > > > On Tue, Jul 12, 2016 at 10:12:36AM +0100, Daniel P. Berrange wrote: > > > > Currently the QEMU processes inherit their core dump rlimit > > > > from libvirtd, which is really suboptimal. This change allows > > > > their limit to be directly controller from qemu.conf instead. > > s/controller/controlled/ > > > > > --- > > > > > > > > Changed in v2: > > > > > > > > - Allow use of string "unlimited" > > > > > > > > src/libvirt_private.syms | 2 ++ > > > > src/qemu/libvirtd_qemu.aug | 1 + > > > > src/qemu/qemu.conf | 16 +++++++++++++++- > > > > src/qemu/qemu_conf.c | 17 +++++++++++++++++ > > > > src/qemu/qemu_conf.h | 1 + > > > > src/qemu/qemu_process.c | 1 + > > > > src/qemu/test_libvirtd_qemu.aug.in | 1 + > > > > src/util/vircommand.c | 14 ++++++++++++++ > > > > src/util/vircommand.h | 1 + > > > > src/util/virprocess.c | 36 ++++++++++++++++++++++++++++++++++++ > > > > src/util/virprocess.h | 1 + > > > > 11 files changed, 90 insertions(+), 1 deletion(-) > > > > > > > > > > [...] > > > > > > > diff --git a/src/qemu/libvirtd_qemu.aug b/src/qemu/libvirtd_qemu.aug > > > > index 8bc23ba..a8edc2b 100644 > > > > --- a/src/qemu/libvirtd_qemu.aug > > > > +++ b/src/qemu/libvirtd_qemu.aug > > > > @@ -72,6 +72,7 @@ module Libvirtd_qemu = > > > > | bool_entry "set_process_name" > > > > | int_entry "max_processes" > > > > | int_entry "max_files" > > > > + | int_entry "max_core" > > > > > > This should be expanded to allow "unlimited" as well. > > > > Opps, yes. > > > > > > diff --git a/src/qemu/qemu_conf.h b/src/qemu/qemu_conf.h > > > > index 510cd9a..b730202 100644 > > > > --- a/src/qemu/qemu_conf.h > > > > +++ b/src/qemu/qemu_conf.h > > > > @@ -148,6 +148,7 @@ struct _virQEMUDriverConfig { > > > > > > > > unsigned int maxProcesses; > > > > unsigned int maxFiles; > > > > + unsigned long long maxCore; > > > > > > > > > > This is not initialized anywhere, effectively making the limit default > > > to 0 IIUC. > > > > Yes, that's correct as per the qemu.conf docs - we don't allow > > core dumps by default, since they can be absolutely massive > > and so have a significant impact on the host OS in terms of time > > & I/O bandwidth required to dump the guest, as well as disk space > > usage. So core dumps are an opt-in thing. > > > > I must've missed the place where we forbade it then. QEMU will just inherit default limits from libvirtd, and libvirtd will get a core file size of 0 from systemd unless you customize the systemd unit file.

Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|