OpenSearch/docs/reference/migration/migrate_6_0/indices.asciidoc

[[breaking_60_indices_changes]]
=== Indices changes

==== Index templates use `index_patterns` instead of `template`

Previously templates expressed the indices that they should match using a glob
style pattern in the `template` field. They should now use the `index_patterns`
field instead. As the name implies you can define multiple glob style patterns
in an array but for convenience defining a single pattern as a bare string is
also supported. So both of these examples are valid:

[source,js]
--------------------------------------------------
PUT _template/template_1
{
  "index_patterns": ["te*", "bar*"],
  "settings": {
    "number_of_shards": 1
  }
}
PUT _template/template_2
{
  "index_patterns": "te*",
  "settings": {
    "number_of_shards": 1
  }
}
--------------------------------------------------
// CONSOLE


==== Shadow Replicas have been removed

Shadow replicas don't see enough usage, and have been removed. This includes the
following settings:

- `index.shared_filesystem`
- `index.shadow_replicas`
- `node.add_lock_id_to_custom_path`

==== Open/Close index API allows wildcard expressions that match no indices by default

The default value of the `allow_no_indices` option for the Open/Close index API
has been changed from `false` to `true` so it is aligned with the behaviour of the
Delete index API. As a result, Open/Close index API don't return an error by
default when a provided wildcard expression doesn't match any closed/open index.

==== Delete a document

Delete a document from non-existing index has been modified to not create the index.
However if an external versioning is used the index will be created and the document
will be marked for deletion. 

==== Indices aliases api resolves indices expressions only against indices

The index parameter in the update-aliases, put-alias, and delete-alias APIs no
longer accepts alias names. Instead, it accepts only index names (or wildcards
which will expand to matching indices).