Re: [PATCH v2] qemu: add append mode config for serial file

On Tue, Jan 10, 2023 at 09:03:40AM +0000, Daniel P. Berrangé wrote: > On Tue, Jan 10, 2023 at 02:42:34PM +0600, Oleg Vasilev wrote: >> Serial log file contains lots of useful information for debugging >> configuration problems. It makes sense to preserve the log in between >> restarts, so that one can later figure out what was going on. Before >> that, we could do that on a per-domain basis, now we can configure it >> once for all domains. > > IMHO this is the job of the mgmt app that is using libvirt. > > We've got a few places in qemu.conf that interact with the > guest config, but I largely consider them to be historical > mistakes that shouldn't be added to. > > Adding this setting specifically for serial devs is opening > up a can of worms IMHO. eg what if you have multiple serial > ports and only want one of them in append mode. There are > many other devices with chardev backends which log to files, > but this setting only touches serial ports.

> > Ultimately append/truncate is a policy decision for the > mgmt app to make, not a libvirt host level tunable. > I agree with that since it allows for more configurability and it is concentrated in one place, the mgmt app.  Defaulting to a value is something that should not be difficult to implement in any controlling application that uses libvirt, so I don't really see the benefit for other mgmt apps either.

> With regards, > Daniel > -- > |: https://berrange.com      -o- > https://www.flickr.com/photos/dberrange :| > |: https://libvirt.org         -o- > https://fstop138.berrange.com :| > |: https://entangle-photo.org    -o- > https://www.instagram.com/dberrange :| >