What is the difference/link between shard rebalancing and shard allocation ?
Is it possible to have a shard rebalancing with a disable sharding allocation ? I don't think so but I need some confirmation.
Furthermore, in the elastic rolling upgrade procedure (https://www.elastic.co/guide/en/elasticsearch/reference/current/rolling-upgrades.html), it is advised to disable shard allocation. My guess is that this step is necessary to prevent the cluster from creating new shards in order to satisfy the number of shards specified for the indices.
I have already read this topic (Difference between 'rebalance.enable' and 'allocation.enable') but I find the explanation quite vague.
Thanks for your help,