}
public void producerStart(String nodeId) throws Exception {
ProducerSwitchCommand command = new ProducerSwitchCommand(clusterManager.generateId());
Node node = clusterManager.findNodeById(nodeId);
if (node == null) {
throw new IllegalArgumentException("Cluster node " + nodeId + " doesn't exist)");
}
Set<Node> nodes = new HashSet<Node>();