This is a reimplementation of check_munin_rrd.pl in Python. It is used as a Nagios plugin command to read data collected from a Munin node by a Munin server.
It uses rrdtool directly via "rrdtool lastupdate". rrdtool is a dependency for Munin servers, so it should be reliably available.
Installation is typical for a Python package; virtualenv is recommended.
Run the check_munin script for options. Command-line options allow you to set domain, host, Munin-node plugin module, various include/exclude filters, and warning/critical ranges. Options generally match check_munin_rrd. Differences: -o option values may be globs; warning/critical specifications may be ranges, e.g., "-w 0:85" for warn when outside 0-85 range.
check_munin -d dcn.org -H www.dcn.org -M df -o "_dev_*" -i _dev_shm -w 85 -c 95
This reads the /var/lib/munin/dcn.org/www.dcn.org RRD files for the "df" module, including only RRD df files that match _dev_* and excluding _dev_shm:
DF WARNING - /dev/sdi is 87.75 (greater than 85) | '/dev/sda1'=42.0611407378;85;95;0 '/dev/sdb'=31.7252599179;85;95;0 '/dev/sdh'=41.0162765108;85;95;0 '/dev/sdi'=87.7540702356;85;95;0 '/dev/sdj'=56.5373419066;85;95;0 '/dev/sdk'=54.4599777102;85;95;0