[spanktar]

True. There is an elected master node and you can configure a cluster to have master-only (non-data) nodes, data-only nodes (non-master eligible), or both. Even still, and even if you choose to set up a cluster this way, every node can perform the same functions, it's more a matter of what responsibility a node has. And even though there is a master node, that master can disappear without consequence, another will be elected in its stead. There is nothing really "special" about a master node.