Cacti is a system monitoring tool that uses rrdtool and made to be able and query SNMP-enabled hardware or services. The result is a platform that allows to write scripts and create graphs for various resources that are accessible from a web-based (apache) interface.

On Debian, one can install Cacti using the following commands:

aptitude install cacti snmp snmpd cacti-spine

which will download the necessary tools and set-up Cacti.

By default, this will create a file an apache alias in /etc/apache2/conf.d/cacti.conf that will serve cacti from any URL served by Apache and by /cacti. A good decision is to restrict that to the local network. In order to do so, we edit /etc/apache2/conf.d/cacti.conf and encompass the configuration in an IP based virtual host by using the directives:

<VirtualHost 192.168.0.1:80>
...
</VirtualHost>

The SNMP that ships with Debian Squeeze does not supply the MIB files that are required for the snmpd daemon to work. For that, we have to edit the apt sources and add the non-free term so we can pull the snmp-mibs-downloader package.

Editing /etc/apt/sources.list we append the term non-free on every line. For example:

deb http://ftp.sv.debian.org/debian/ squeeze main non-free

This has to be done for every line.

Then, we update the sources:

aptitude update

and install snmp-mibs-downloader. During the setup of the snmp-mibs-downloader package, the necessary MIBs are downloaded.

Next, we edit /etc/default/snmpd and comment out the MIBs line:

#export MIBS=

then, comment out the line:

#mibs :

in /etc/snmp/snmp.conf.

Finally, to enable SNMP for the local host, we edit /etc/snmp/snmpd.conf and enable the line:

rocommunity public  localhost

Now we can start the snmpd daemon by issuing:

service snmpd restart

We can query the SNMP server by issuing the command:

snmpwalk -v1 -cpublic localhost

if you get Cannot adopt OID then track back and install the snmp-mibs-downloader package. Otherwise, SNMP works fine.

To configure cacti, you can now log-in using a browser and pointing it to http://192.168.0.1/cacti (assuming that 192.168.0.1 is the IP of the server you are installing Cacti on).

The default credentials when logging in the first time are:

username: admin
password: admin

which will prompt you to change the password.

Next, make the following configuration changes to enable the spine poller:

• Configuration →
  • Settings →
    • Poller →
      • Poller Type → spine

Now, we enable SNMP by following:

• Management →
  • Devices →
    • localhost (or the name of the server) →
      • Host Template → Generic SNMP-enabled Host
      • SNMP Version → Version 2
      • Save
      • Downed Device Detection → SNMP

The order is important: setting SNMP version 2, will allow you to set the downed device detection to SNMP as well.

Now we can create new graphs by using SNMP. At the top, follow the Create Graphs for this Host and you are ready to go.

The Cacti template section contains a full complement of templates that can be added.