At $dayjob, the Nagios server runs on FreeBSD. Rather than porting Thruk to FreeBSD, we run it on a separate Linux VM (and just use the Debian package). However, that poses some problems with backend availability.

The MK Livestatus documentation suggests using xinetd and gives an example. However, the FreeBSD server in question runs stock inetd, and I didn’t want to change it. Further, the stock inetd causes a new process to be spawned with each query. This results in occasional backend timeout issues on even a lightly-loaded Thruk installation.

So, instead of using [x]inetd, I went with socat. The config was pretty simple after installing from ports:

/etc/rc.conf:
socat_enable="YES"
socat_flags="TCP4-LISTEN:6557,fork,reuseaddr UNIX-CONNECT:/var/spool/nagios/rw/live"

The new socat method is more efficient and reliable that using inetd to spawn a new process for every socket connection.

Since Thruk is happy connecting with a network socket, I didn’t bother recreating the FreeBSD Nagios’s server’s domain socket over to the Linux Thruk server. However, doing so would simply have been a matter of using another socat configuration on the side of the Thruk server. i.e.

socat UNIX-LISTEN:/var/lib/thruk/live,fork,user=www-data,group=www-data TCP:[$NAGIOS_SERVER_IP]:6557

If I wanted too, I could even use socat’s SSL encryption over the wire to protect the contents of the livestatus shell.