How to prevent Domain Controller being a single point of failure in cluster?

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http://serverfault.com – There is cluster of Five Node A1(Apache + mod_clusrer) for load balancing and N1 ,N2 ,N3 and N4 are Jboss As 7 . Here N1 is master Node. Cluster of N1+N2+N3+N4. What will happen if Master Node (domain controller) N1 will crash or shutdown. There is N2+N3+N4 still work as simple cluster ? Means what will happen with "HttpSession" or "Infinispan". Will these cache work normal in "Distributed" or "Replicated" Mode in case of Master node crash. Will Apache+ModCluster will get proper status information about the cluster of remaining Node (N2+N3+N4). What should be do to "Deploy" or "Undep (HowTos)