Configuring Munin on a Debian 7 system for monitoring of server.

Following this, we’ll install all we need to make munin service run and be optimized to what we need to monitor.

Lets install munin:

apt-get install munin munin-node munin-plugins-extra

Let’s enable some default plugins:

cd /etc/munin/plugins
ln -s /usr/share/munin/plugins/mysql_ mysql_
ln -s /usr/share/munin/plugins/mysql_bytes mysql_bytes
ln -s /usr/share/munin/plugins/mysql_innodb mysql_innodb
ln -s /usr/share/munin/plugins/mysql_isam_space_ mysql_isam_space_
ln -s /usr/share/munin/plugins/mysql_queries mysql_queries
ln -s /usr/share/munin/plugins/mysql_slowqueries mysql_slowqueries
ln -s /usr/share/munin/plugins/mysql_threads mysql_threads

Now let’s start editing the server configuration:

vi /etc/munin/munin.conf

More or less you should see something like this.

# Example configuration file for Munin, generated by 'make build'
 
# The next three variables specifies where the location of the RRD
# databases, the HTML output, logs and the lock/pid files.  They all
# must be writable by the user running munin-cron.  They are all
# defaulted to the values you see here.
#
dbdir   /var/lib/munin
htmldir /var/cache/munin/www
logdir /var/log/munin
rundir  /var/run/munin
 
# Where to look for the HTML templates
#
tmpldir /etc/munin/templates
 
# Where to look for the static www files
#
#staticdir /etc/munin/static
 
# temporary cgi files are here. note that it has to be writable by
# the cgi user (usually nobody or httpd).
#
# cgitmpdir /var/lib/munin/cgi-tmp
 
# (Exactly one) directory to include all files from.
includedir /etc/munin/munin-conf.d
[...]
# a simple host tree
[server1.example.com]
    address 127.0.0.1
    use_node_name yes
[...]

Now to finish the default’s lets restart munin and apache:

service apache2 restart
service munin-node restart

Some advanced stuff:

We need to check that we’re not missing any libraries for Munin to work correctly for this; let’s run:

munin-node-configure --suggest

Here a long list will appear saying what you’re missing, it’s common to see with MYSQL you’re missing cache pearl libs… so

apt-get install libcache-cache-perl

To work with plugins, you’ll be creating and removing system links, so…

cd /etc/munin/plugins
ln -s /usr/share/munin/plugins/apache_accesses

That would be an example on how to work with plugins.

I NEED BIND9!

Okay, don’t get crazy, lets work with bind9 and munin.

In: /etc/bind/named.conf.options we need to enable stat’s file, add the following line.

statistics-file "/var/cache/bind/named.stats";
logging {
        channel b_query {
                file "/var/log/bind9/query.log" versions 2 size 1m;
                print-time yes;
                severity info;
        };
        category queries { b_query; };
};

/var/log/bind9 > add that path, and chown to bind, and allow it to write the log there.

Next, lets tell munin to process that:

vi /etc/munin/plugin-conf.d/munin-node

[bind9]
user root
env.logfile   /var/log/bind9/query.log
 
[bind9_rndc]
user root
env.querystats /var/cache/bind/named.stats

Once that is done, lets make the symlinks.

ln -s /usr/share/munin/plugins/bind9 /etc/munin/plugins/bind9
ln -s /usr/share/munin/plugins/bind9_rndc /etc/munin/plugins/bind9_rndc

As usual restart munin-node!

DONE!.

REMEMBER TO RM [SYMLINKS] to plugins you don’t need, or Munin can turn into a huge memory hog… in my experience bind9 plugin… take’s a long time to process, leading to a sluggish system.