[syslog-ng] line of sendmail log output missing?

Balazs Scheidler bazsi at balabit.hu
Sat May 5 07:55:51 CEST 2007

On Fri, 2007-05-04 at 16:12 -0400, Centyx Centalix wrote:
> On 04May2007 05:40PM (+0200), Balazs Scheidler wrote:
> > consistently losing a log message is strange, are you sure nothing else
> > changed but the migration to syslog-ng? I have only seen losing messages
> > like this when a process runs in a chroot-ed environment, with an
> > inherited connection to /dev/log from the outside. Once the logger is
> > restarted (regardless whether it is syslogd or syslog-ng), /dev/log gets
> > reopened and the process stuck in a chroot cannot reconnect to /dev/log.
> > 
> > The solution is to open a /dev/log socket inside the chroot as well, in
> > this way when the chrooted child loses its /dev/log connection, it can
> > reopen it and happily log onwards.
> > 
> > The exact scenario I described happened with postfix but could apply to
> > sendmail as well.
> > 
> > -- 
> > Bazsi
> > 
> I am nearly certain that the syslog-ng migration is the culprit, as the
> timestamps in the logs when the change occurred ( this is happening on multiple
> servers ) are consistent with the times the switch was made to syslog-ng.
> Furthermore, I have even tried switching back to syslogd on one of the
> servers to see if this log message returns, and it does. Strange, indeed.
> /home/virtual/FILESYSTEMTEMPLATE/log- is used inside of many chroots, but is created as a hardlink in the chrooted environments, so I wouldn't think that this would be an issue. However, it would make sense that the local delivery logs were missing if syslog-ng were having problems w/ the log device that was used by the chroot. How may I go about troubleshooting that the log device is functioning properly and being read by syslog-ng?

You can use logger to send syslog messages to a custom log socket. Try

$ logger -u "path to log device in chroot" message 

and see whether it gets through. I'm not sure the hard-link way would
work, as syslog-ng removes and recreates log sockets as it starts.


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