High available hadoop cluster

One of the problems which is being discussed with the Hadoop cluster was that is not high available due to the name node failure, as it single point of failure, so here is new version of  Hadoop that is coming with high avalibility option that is two  NameNode  , where the switching of  NameNode  will happen automatically as one  NameNode  goes down, the other will take charge meanwhile we can check the problem with the name node,

The proposed design follows:

So you can thin it of two cluster interconnected using switches and high speed communication line.

so mainly this will be dependent a service called heartbeat that will check the aliveness of NameNode if one goes down the redirection will be done automatically.

We can see the it as follow too: