Relocate primary shards first while excluding set of nodes

[jainankitk]

Is your feature request related to a problem? Please describe.
When some node or set of nodes is excluded, the shards are moved away in random order. It might relocate all copies of same shard first over any copy of some shard that reduces availability.

Describe the solution you'd like
Whenever some node or set of nodes is excluded, we move away primary or atleast one copy of every shard before relocating other copies of the same shard