Elasticsearch Version: 6.5.4

There are 16 nodes in my cluster and the index has 10 shards.

There is a new index created everyday.

It works well for several months.

But a strange thing happen today. 10 shards of the new index are allocated to on node.

enter image description here

I’m sure all nodes are working well. None node or procession restarting.

How can this happen?

2

There is a simple solution using index setting index.routing.allocation.total_shards_per_node

https://www.elastic.co/guide/en/elasticsearch/reference/master/allocation-total-shards.html#allocation-total-shards