Module Nn_config

         netplex {
           ...
           namenodes {
             clustername = "cluster1";  (* required *)
             node { addr = "hostname:port" };
             node { addr = "hostname:port" };
             ...
             hostname = "hostname";     (* optional *)
             timeout = 60.0;            (* optional *)
             alive_min = 1;             (* optional *)
             alive_min_startup = 1;     (* optional *)
             elect_timeout 300.0;       (* optional *)
             rank = "0";                (* mandatory *)
             replication = 3;           (* optional *)
             inodecache { port = <port> };
           }
           datanodes {
             node { addr = "hostname:port" }
             node { addr = "hostname:port" }
             ...
             timeout = 60.0;            (* optional *)
             blocksize = 65536;         (* mandatory *)
           }
           ...
         }
      

The parameter rank can also be given by running a script that outputs the rank to stdout. This script must be given as parameter rank_script.

Instead of describing the nodes directly in the config file using node subsections, one can also point to external file:

 
         node_list = "filename";
         port = <default_port>;
      

These two parameters can replace both the node subsections for namenodes and for datanodes. The external file enumerates the hosts, one hostname a line (with shell-style comments).

Special values:

• alive_min and alive_min_startup can also be set to "all" (in double quotes). This means all configured name nodes must be available
• replication can also be set to "max" (in double quotes). This means that the replication is set to the number of data nodes.