public void run()
    {
        while (running) {
            // poll the nodes
            for (Node node : nodes) {
                node.poll();
            }

            resourceManager.scheduleJobs();

            // sleep
            try {
                Thread.sleep(pollSleep);
            } catch (InterruptedException ex) {
                assert (false) : "Cluster poll thread was interrupted";
            }
        }
    }