@Override
    public void allocatePorts(int start, PortAllocBridge from) {
        if (requiresWantedPort()) {
            from.requirePort(start++, "rpc");
            from.requirePort(start++, "http");
        } else if (start == 0) {
            from.allocatePort("rpc");
            from.allocatePort("http");
        } else {
            from.wantPort(start++, "rpc");
            from.wantPort(start++, "http");
        }
    }
Represents a Configserver. There may be one or more Configservers in a
Vespa system.

NOTE: The Configserver is not started by the config system, and
does not receive any config. It's included here so we know what host
it runs on, and to give an error message if another service tries
to reserve the ports it is using.

@author  gjoranv
config-model/src/main/java/com/yahoo/vespa/model/admin/Configserver.java