Today when we create an index we return immediately after executing sanity checks and adding metadata to the cluster-state. Yet, we don't wait for any kind of allocations etc. such that an index can be created with more replicas than nodes in the cluster and once it's closed it can't be reopened since reopening an index requires a quorum of the replicas for each shard. If such an index is reopened the shards that have no quorum / not enough replicas are found in the cluster will just not be allocated at all.

Unfortunately not even waiting for yellow will help here since it means waiting for the primary to be allocated which might not be enough in the case of #replicas > 1.

There are a couple of things we can do here to improve the situation:

• Add another wait to the cluster health to wait for quorum
• By default wait for quorum for the index when an index is created
• By default reject closing an index if less than the quorum of shards is allocated