Re: [libvirt] [PATCH 2/6] Save daemon logs to libvirtd.log

On Thu, Mar 03, 2011 at 06:22:13PM +0800, Daniel Veillard wrote: > > Depending on whether it's run as root or user, the log is saved > in the local state dir or in $HOME/.libvirt. The file descriptor > is kept as a global variable used by following patches. > * daemon/libvirtd.c: add libvirtd.log as the output for logs > > Signed-off-by: Daniel Veillard <veillard(a)redhat.com&gt; > --- > daemon/libvirtd.c | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++--- > 1 files changed, 85 insertions(+), 5 deletions(-) I don't think doing this is a good idea for a couple of reasons. First, I find that many people have already altered the libvirtd.conf file to log to /var/log/libvirtd.log by default instead of syslog. Second, when you have the log priority set to debug as this patch does, the logfile can get *VERY* large *VERY* quickly. eg, when

RHEV is using libvirt it is not uncommon to see a 300 MB of logs generated in a mere 10 minutes, just from a fairly tightly targetted filter like '1:qemu 1:util 1:libvirt'. If we write all logs unfiltered at debug priority, then we will easily hit > 1 GB of data in < 10 mins. This patch isn't allowing admins any way to turn off this extra libvirtd.log in the cases where they are already collecting the data via a different log output.

I agree with the idea of having a dedicated libvirtd.log file by default though. So why don't we just change our default logging configuration to use a logfile, instead of syslog. eg change this block of code in libvirtd.c: if (godaemon) { if (virAsprintf(&tmp, "%d:syslog:libvirtd", virLogGetDefaultPriority()) < 0) goto no_memory; } else { if (virAsprintf(&tmp, "%d:stderr", virLogGetDefaultPriority()) < 0) goto no_memory; } To be if (privileged) { if (virAsprintf(&tmp, "%d:file:/var/log/libvirt/libvirtd.log", virLogGetDefaultPriority()) < 0) goto no_memory; } else { char *userdir = virGetUserDirectory(geteuid()); if (!userdir) goto no_memory; if (virAsprintf(&tmp, "%s/.libvirt/libvirtd.log", userdir) < 0) { VIR_FRE(userdir); goto no_memory; } VIR_FRE(userdir); }

Thus people can just adjust 'log_debug' or 'log_filters' settings in libvirtd.conf if they want more verbose logging.