Deleting an index

The counterpart of creating an index is deleting one. Deleting an index means deleting its shards, mappings, and data. There are many common scenarios when we need to delete an index, such as the following:

• Removing the index to clean unwanted or obsolete data (for example, old Logstash indices).
• Resetting an index for a scratch restart.
• Deleting an index that has some missing shards, mainly due to some failures, to bring the cluster back in a valid state. (If a node dies and it's storing a single replica shard of an index, this index will be missing a shard, and so the cluster state becomes red. In this case, you'll bring back the cluster to a green status, but you will lose the data contained in the deleted index.)