We have some Linux web servers that we use for Moodle they are setup behind a Barracuda Load Balancer that then distributes the load based on how busy each of the web servers are. Essentially the more busy the server the less clients it is given to process. The barracuda load balancer uses an SNMP query determining the current load. The Barracuda load balancer side is well documented, but the configuration on your Linux box is not so much, so assuming you've configured the Barracuda you just need to follow these steps on the 14.04 LTS Ubuntu server. Remember this is a basic configuration, offering basic security, so if you are looking to do this you need to review these settings, but this gives a basic operational configuration. Firstly install SNMPD (the SNMP agent) that can respond to SNMP queries:
Now download the SNMP MIBS, these are not included in the SNMP package anymore you need to get them separately with this.
Once this is done you need to replace the /etc/snmp/snmpd.conf file with the following, this will allow you to access this SNMP agent from any host on the 192.168.0.0/24 network using the community string: "mycommunitystring."
To get the SNMPD daemon to take the setting restart it:
Now from another Linux box you should be able to get the CPU load back using SNMPWalk to test with:
If it works you should see something like: UCD-SNMP-MIB::laLoad.1 = STRING: 0.04 Now using the Test button on the Barracuda Load Balancer configuration, you can test the SNMP load balancing you should see it calculating a metric based on the current load of the server. Additional Links: |
General IT >