One node have less shards then the others

Hi ,

we have a 9 node cluster where one node has almost half shards then the others but using more capacity then others.

what could be the reason of this behavour ? and how can it be solved , rebalance ?

by the way all shards that placed on the node are primary without replicas .

Thanks in advance.

looks like that node has a disk full enough to trigger the storage watermarks, so no new shards will get allocated there. The elasticsearch log on the master node is likely reporting this.

You can also see what's up by manually rerouting a shard to that node using the cluster reroute API with the explain parameter set. Way at the bottom of the response JSON, you will see the reason why it refuses.

As an aside, that is a LOT of total shards.

Thank you