Date: Mon, 29 Apr 2019 22:32:50 +0700 From: Victor Sudakov <vas@mpeks.tomsk.su> To: FreeBSD virtualization <freebsd-virtualization@freebsd.org> Subject: Re: [vm-bhyve] shutting down VMs and kern.init_shutdown_timeout Message-ID: <20190429153250.GA93256@admin.sibptus.ru> In-Reply-To: <CA%2BtpaK3POYWEpMgnWCV6NeRcPqE2skB8xt2sw0WUwFYYuYR%2BRw@mail.gmail.com> References: <20190428044118.GA46284@admin.sibptus.ru> <1DE7A90B-E3AB-4F1E-9A3A-981B18751F8E@punkt.de> <20190429082408.GA84142@admin.sibptus.ru> <CA%2BtpaK3POYWEpMgnWCV6NeRcPqE2skB8xt2sw0WUwFYYuYR%2BRw@mail.gmail.com>
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[-- Attachment #1 --] Adam wrote: > > > Patrick M. Hausen wrote: > > > > > > > Am 28.04.2019 um 06:41 schrieb Victor Sudakov <vas@mpeks.tomsk.su>: > > > > "if the /etc/rc.shutdown does not terminate within 120 seconds, init > > will > > > > terminate it. The timeout can be configured via the sysctl variable > > > > kern.init_shutdown_timeout.“ > > > > > > > What’s keeping you from increasing that timeout for your > > > particular requirements? > > > > Is that really necessary? Am I correct assuming that any VM is supposed > > to shut down within 2 minutes or else the bhyve processes will be > > killed? Or is this kern.init_shutdown_timeout only about the rc.shutdown > > script itself and not its children? > > > > FreeBSD is tuned as a general purpose server OS. If you find the defaults > don't meet your needs, you can change them. That's why tunables exist. Adam, if you know the answer to my direct question above, please answer it. I also would like to know if there are any adverse effects of increasing kern.init_shutdown_timeout. > > > IMHO 2 minutes are a reasonable > > > default for a system that does not run hypervisor VMs - > > > which is probably the vast majority. > > > > > > Anyone with the knowledge to implement a virtualized > > > environment > > > > The lack of information about this caveat in > > https://wiki.freebsd.org/bhyve, man vm-bhyve, > > > > https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/virtualization-host-bhyve.html > > and other sources suggests that this particular knowledge may be > > limited. Other hypervisors (non-bhyve) probably wait for all VMs to stop. > > > > RH implemented this relatively recently. > > https://bugzilla.redhat.com/show_bug.cgi?id=1334982 Good for them. We need to raise awareness too, so I've created this PR https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=237646 > > > can simply set that to a more suitable value, > > > can’t he/she? > > > > Yes if they know about it. There should be a warning somewhere in the > > documentation if we want to be serious about FreeBSD as a hypervisor. > > > > Or better still, a warning that rcshutdown_timeout (if set) and > > kern.init_shutdown_timeout can be too low when running vm-bhyve and > > such is desirable. > > > > Why don't you simply write a wrapper script which calls shutdown after > shutting down guests? A lot of things can be done to mitigate this problem, as soon as you are aware of it. > I doubt many admins on any hypervisor are > gratuitously calling shutdown on host with important guests running. Well, after I started noticing "WARNING: / was not properly dismounted" in my guest OS's logs, after the perfectly correct shutdown of the host, I stopped calling shutdown on host, and started thinking why this was happening. But not before. -- Victor Sudakov, VAS4-RIPE, VAS47-RIPN 2:5005/49@fidonet http://vas.tomsk.ru/ [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJcxxkiAAoJEA2k8lmbXsY0yuwH/2SmdD1dU/5jqfx5K9qNntOW RT9dWeXrdNXI3zoS2Uu/t1yNQpJApvB2ay3svceq4GK4DEKAYbtoJd1Ib6EVCeeX mlbQFk0keSFiXg0jKjtGTJ13LL4+hJLG6zpNgNoxAv/HwOiPk1PXjT7rA0AyqF18 PgVyZYHREY1OBzWcUlTguKbmjxzrnD+W1drHrJhH53hH1DkOzrMXvOQT6QVFwBup KOE8OI0HgFkO0pYOfLR/xmRg+zENVG26TPCeZnulND/XRAOqjJ/lfB5tBRxO0ujR eF75wswPAlL1hjp0d7nkVRPQnjGOrM67kYHiwye9enR/tnuJwpGtbOuNPh2WcdY= =ONRq -----END PGP SIGNATURE-----help
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