Enable apache2 status collection. 

Edit the following config and add the below section.
nano /etc/apache2/mods-enabled/status.conf

<Location /server-status>
    SetHandler server-status
    Order deny,allow
    Deny from all
    Allow from 127.0.0.1 ::1
</Location>

Make sure that ( ExtendedStatus is set to On )
apt-get install libwww-perl
apt-get install xinetd
(SERVER) On Observium server run the following. To copy the file to the server you want to monitor.
scp /opt/observium/scripts/observium_agent_xinetd user@your_server:/etc/xinetd.d/observium_agent_xinetd
Change 127.0.0.1 to the ip of your Observium server.
nano /etc/xinetd.d/observium_agent_xinetd
service xinetd restart
(SERVER) On Observium server run the following. To copy the file to the server you want to monitor.
scp /opt/observium/scripts/observium_agent user@your_server:/usr/bin/observium_agent
Create the following directory to store the scripts.
mkdir -p /usr/lib/observium_agent/local
(SERVER) On Observium server run the following. To copy the file to the server you want to monitor.
scp /opt/observium/scripts/agent-local/SCRIPT_THAT_YOU_WANT user@your_server:/usr/lib/observium_agent/local
make the script that you copied exactable 
chmod +x /usr/lib/observium_agent/local/SCRIPT_THAT_YOU_WANT
(SERVER) Edit config.. Add the the below ($config) to the config.php
nano /opt/observium/config.php
$config['poller_modules']['unix-agent']                   = 1;
Restart the xinetd service.
service xinetd restart
(SERVER) From the observium server run the following.
telnet your_server_to_monitor 36602