I've a cluster with one node, and two indices(5 primary shards), with replica shards as 1,2 respectively for each of the indices, The cluster status shows red, 'cause the one index with 2 replicas doesn't have the primary started(I wonder why?), But when I start other node, the status turns yellow, and after killing the new node, the status seems to be yellow, Why is the new node needed to start the primary of the the second index?