@Override
    public void allocatePorts(int start, PortAllocBridge from) {
        int port = (start == 0) ? getWantedPort() : start;
        from.requirePort(port++, "rpc");
        from.requirePort(port++, "unused/1");
        from.requirePort(port++, "unused/2");
        from.requirePort(port++, "unused/3");
    }
Returns the number of ports needed by the logserver.
config-model/src/main/java/com/yahoo/vespa/model/admin/Logserver.java