Description
OCO is software that we use on our infrastructure to know the status of servers. Each server running in a cluster should check and tell others if it is ok or not. OCO is compatible with load balancing cards Cisco SLB type / ACE (SMTP probe).

We use port 79 for communication. It is extremely easy. It connects to the port and the server says "OK" or "KO" if the connection is cut.

Install and Configure

Type this command to retrieve OCO:


This command allows you to decompress and install OCO:


The load balancing system in OVH is compatible with OCO. If you choose in the manager "Probe Software, the infrastructure will check periodically (every 60 seconds) to your server (your OCO) and the server will say "OK" or "KO". If "KO", automatically the server will be removed from the cluster. And if it say "OK" again, it will be added back into the cluster. You can check this very easily as follows:



You put the OCO into "KO" then you look what happens to the load balancing. Then you turn into "OK" with the OCO




You should add it to your machine's network interface address of the loadbalancer.
You can use this guide, using the lo interface and eth0: IpAlias

OCO is under the GPL licence.