We recently had the case that multiple nodes of our ElasticSearch cluster running version 7.3.2 reached the low watermark threshold.
We immediately added some nodes to counteract the increase in disk usage and made a call to /_cluster/reroute.
However, shards of the low watermark nodes were not relocated until we excluded one of the nodes via _cluster setting. After that, all nodes recovered subsequently.
What would be the best practice for handling low watermark issues?
Is there a better way to start the relocation process for shards?