Date: Mon, 11 Mar 2019 11:02:59 -0700 (PDT) From: "Rodney W. Grimes" <freebsd-rwg@gndrsh.dnsmgr.net> To: Mark Raynsford <list+org.freebsd.virtualization@io7m.com> Cc: Shawn Webb <shawn.webb@hardenedbsd.org>, freebsd-virtualization@freebsd.org Subject: Re: bhyve: Detecting that a guest kernel has booted Message-ID: <201903111802.x2BI2xTK010732@ gndrsh.dnsmgr.net> In-Reply-To: <20190311174635.63a071e2@almond.int.arc7.info>
next in thread | previous in thread | raw e-mail | index | archive | help
> On 2019-03-11T13:27:23 -0400 > Shawn Webb <shawn.webb@hardenedbsd.org> wrote: > > > > Both FreeBSD and Linux supports virtio_console(4). I have no idea > > about OpenBSD, but I'm sure they'd be open to an implementation if > > asked. > > Right. > > > > > The NFS solution would work, but it would be somewhat fragile. What > > happens when a VM crashes? What happens when the host crashes? > > At least in my case: > > If the VM crashes, it'll be restarted by a process supervisor (runit, > here). I think ping would suffice to make that determination? > If the host crashes, I likely have bigger problems. In any case, I > think that's still fine because all the host would care about is if the > guest's file was touched more recently than the last time the host > tried to start a bhyve process for it. You could inside the vm simply touch /tmp/foo from cron and from the host see that the diskimage last modified time updated. Assuming some cacheing does not get in the way. > I suppose I should elaborate a bit: I do have monitoring via Prometheus > in place, but I'd like to try to stagger VM startups a little as > starting up a lot of them in parallel on boot tends to overwhelm the > machine slightly. Once they're all up and running in a steady state, > things are fine. I would typically stagger the startup of > ordinary services (inside a jail, for example) by using dependencies in > runit - it has a facility to pause a service until a dependent service > has been started. Unfortunately, that can't work in this case because > once the bhyve process has been started, the host can't tell if/when > the guest has actually fully started up. As far as runit is concerned, > the service is up and so any dependent services should be started too. The package vmbhyve has starggered startup in a specific ordered list implemented. It is all writtin in /bin/sh, so easy to adapt. > Mark Raynsford | http://www.io7m.com -- Rod Grimes rgrimes@freebsd.org
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201903111802.x2BI2xTK010732>