[DOCS] Add alias guide (#73062)

Creates a guide for aliases. We can use this guide to house concepts, examples,
and tips for aliases.

docs/reference/alias.asciidoc

@@ -0,0 +1,326 @@
+[chapter]
+[[alias]]
+= Aliases
+
+An alias is a secondary name for a group of data streams or indices. Most {es}
+APIs accept an alias in place of a data stream or index name.
+
+You can change the data streams or indices of an alias at any time. If you use
+aliases in your application's {es} requests, you can reindex data with no
+downtime or changes to your app's code.
+
+[discrete]
+[[alias-types]]
+=== Alias types
+
+There are two types of aliases:
+
+* A **data stream alias** points to one or more data streams.
+* An **index alias** points to one or more indices.
+
+An alias cannot point to both data streams and indices. You also cannot add a
+data stream's backing index to an index alias.
+
+[discrete]
+[[add-alias]]
+=== Add an alias
+
+To add an existing data stream or index to an alias, use the
+<<indices-aliases,aliases API>>'s `add` action. If the alias doesn't exist, the
+request creates it.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "add": {
+        "index": "logs-nginx.access-prod",
+        "alias": "logs"
+      }
+    }
+  ]
+}
+----
+// TEST[s/^/PUT _data_stream\/logs-nginx.access-prod\n/]
+
+The API's `index` and `indices` parameters support wildcards (`*`). If a
+wildcard pattern matches both data streams and indices, the action only uses
+matching data streams.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "add": {
+        "index": "logs-*",
+        "alias": "logs"
+      }
+    }
+  ]
+}
+----
+// TEST[s/^/PUT _data_stream\/logs-nginx.access-prod\n/]
+
+[discrete]
+[[remove-alias]]
+=== Remove an alias
+
+To remove an alias, use the aliases API's `remove` action.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "remove": {
+        "index": "logs-nginx.access-prod",
+        "alias": "logs"
+      }
+    }
+  ]
+}
+----
+// TEST[continued]
+
+[discrete]
+[[multiple-actions]]
+=== Multiple actions
+
+You can use the aliases API to perform multiple actions in a single atomic
+operation.
+
+For example, the `logs` alias points to a single data stream. The following
+request swaps the stream for the alias. During this swap, the `logs` alias has
+no downtime and never points to both streams at the same time.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "remove": {
+        "index": "logs-nginx.access-prod",
+        "alias": "logs"
+      }
+    },
+    {
+      "add": {
+        "index": "logs-my_app-default",
+        "alias": "logs"
+      }
+    }
+  ]
+}
+----
+// TEST[s/^/PUT _data_stream\/logs-nginx.access-prod\nPUT _data_stream\/logs-my_app-default\n/]
+
+[discrete]
+[[add-alias-at-creation]]
+=== Add an alias at index creation
+
+You can also use a <<indices-component-template,component>> or
+<<indices-put-template,index template>> to add index aliases at index creation.
+You cannot use a component or index template to add a data stream alias.
+
+[source,console]
+----
+# Component template with index aliases
+PUT _component_template/my-aliases
+{
+  "template": {
+    "aliases": {
+      "my-alias": {}
+    }
+  }
+}
+
+# Index template with index aliases
+PUT _index_template/my-index-template
+{
+  "index_patterns": [
+    "my-index-*"
+  ],
+  "composed_of": [
+    "my-aliases",
+    "my-mappings",
+    "my-settings"
+  ],
+  "template": {
+    "aliases": {
+      "yet-another-alias": {}
+    }
+  }
+}
+----
+// TEST[s/,\n    "my-mappings",\n    "my-settings"//]
+// TEST[teardown:data_stream_cleanup]
+
+You can also specify index aliases in <<indices-create-index,create index API>>
+requests.
+
+[source,console]
+----
+# PUT <my-index-{now/d}-000001>
+PUT %3Cmy-index-%7Bnow%2Fd%7D-000001%3E
+{
+  "aliases": {
+    "my-alias": {}
+  }
+}
+----
+
+[discrete]
+[[view-aliases]]
+=== View aliases
+
+To get a list of your cluster's aliases, use the <<indices-get-alias,get alias
+API>> with no argument.
+
+[source,console]
+----
+GET _alias
+----
+// TEST[s/^/PUT _data_stream\/logs-nginx.access-prod\nPUT logs-nginx.access-prod\/_alias\/logs\n/]
+
+Specify a data stream or index before `_alias` to view its aliases.
+
+[source,console]
+----
+GET my-data-stream/_alias
+----
+// TEST[s/^/PUT _data_stream\/logs-nginx.access-prod\nPUT logs-nginx.access-prod\/_alias\/logs\n/]
+// TEST[s/my-data-stream/logs-nginx.access-prod/]
+
+Specify an alias after `_alias` to view its data streams or indices.
+
+[source,console]
+----
+GET _alias/logs
+----
+// TEST[s/^/PUT _data_stream\/logs-nginx.access-prod\nPUT logs-nginx.access-prod\/_alias\/logs\n/]
+
+[discrete]
+[[write-index]]
+=== Write index
+
+If an alias points to multiple indices, you can use `is_write_index` to specify
+a write index. {es} routes any write requests for the alias to this index.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "add": {
+        "index": "my-index-2099.05.06-000001",
+        "alias": "my-alias"
+      }
+    },
+    {
+      "add": {
+        "index": "my-index-2099.05.07-000002",
+        "alias": "my-alias",
+        "is_write_index": true
+      }
+    }
+  ]
+}
+----
+// TEST[s/^/PUT my-index-2099.05.06-000001\nPUT my-index-2099.05.07-000002\n/]
+
+TIP: We recommend using data streams to store append-only time series data. If
+you frequently update or delete existing time series data, use an index alias
+with a write index instead. See
+<<manage-time-series-data-without-data-streams>>.
+
+If an alias points to multiple indices with no write index, the alias rejects
+write requests. If an alias points to one index and `is_write_index` is not set,
+the index automatically acts as the write index. Data stream aliases do not
+support `is_write_index`.
+
+[discrete]
+[[filter-alias]]
+=== Filter an alias
+
+The `filter` option uses <<query-dsl,Query DSL>> to limit the documents an alias
+can access. Data stream aliases do not support `filter`.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "add": {
+        "index": "my-index-2099.05.07-000002",
+        "alias": "my-alias",
+        "is_write_index": true,
+        "filter": {
+          "range": {
+            "@timestamp": {
+              "gte": "now-1d/d",
+              "lt": "now/d"
+            }
+          }
+        }
+      }
+    }
+  ]
+}
+----
+// TEST[s/^/PUT my-index-2099.05.07-000002\n/]
+
+[discrete]
+[[alias-routing]]
+=== Routing
+
+Use the `routing` option to <<mapping-routing-field,route>> requests for an
+alias to a specific shard. This lets you take advantage of
+<<shard-request-cache,shard caches>> to speed up searches. Data stream aliases
+do not support routing options.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "add": {
+        "index": "my-index-2099.05.06-000001",
+        "alias": "my-alias",
+        "routing": "1"
+      }
+    }
+  ]
+}
+----
+// TEST[s/^/PUT my-index-2099.05.06-000001\n/]
+
+Use the `index_routing` and `search_routing` to use different routing values for
+indexing and search. If specified, these options overwrite the `routing` value
+for their respective operations.
+
+[source,console]
+----
+POST _aliases
+{
+  "actions": [
+    {
+      "add": {
+        "index": "my-index-2099.05.06-000001",
+        "alias": "my-alias",
+        "search_routing": "1",
+        "index_routing": "2"
+      }
+    }
+  ]
+}
+----
+// TEST[s/^/PUT my-index-2099.05.06-000001\n/]

docs/reference/cat/alias.asciidoc

@@ -4,8 +4,8 @@
 <titleabbrev>cat aliases</titleabbrev>
 ++++
 
-Returns information about currently configured aliases to indices, including
-filter and routing information.
+Retrieves the cluster's <<alias,index aliases>>, including filter and routing
+information. The API does not return data stream aliases.
 
 
 [[cat-alias-api-request]]

docs/reference/glossary.asciidoc

@@ -15,7 +15,7 @@ https://github.com/elastic/stack-docs/tree/master/docs/en/glossary
 // tag::alias-def[]
 An alias is a secondary name for a group of <<glossary-data-stream,data
 streams>> or <<glossary-index,indices>>. Most {es} APIs accept an alias in place
-of a data stream or index name.
+of a data stream or index name. See {ref}/alias.html[Aliases].
 // end::alias-def[]
 
 [[glossary-analysis]] analysis::

docs/reference/index.asciidoc

@@ -33,6 +33,8 @@ include::data-streams/data-streams.asciidoc[]
 
 include::ingest.asciidoc[]
 
+include::alias.asciidoc[]
+
 include::search/search-your-data/search-your-data.asciidoc[]
 
 include::query-dsl.asciidoc[]

docs/reference/indices.asciidoc

@@ -89,37 +89,36 @@ For more information, see <<index-templates, Index Templates>>.
 * <<dangling-index-import>>
 * <<dangling-index-delete>>
 
-
+include::indices/alias-exists.asciidoc[]
 include::indices/aliases.asciidoc[]
 include::indices/analyze.asciidoc[]
 include::indices/clearcache.asciidoc[]
 include::indices/clone-index.asciidoc[]
 include::indices/close.asciidoc[]
 include::indices/create-index.asciidoc[]
-include::indices/put-component-template.asciidoc[]
 include::indices/add-alias.asciidoc[]
+include::indices/put-component-template.asciidoc[]
 include::indices/put-index-template.asciidoc[]
 include::indices/put-index-template-v1.asciidoc[]
 include::indices/delete-component-template.asciidoc[]
 include::indices/dangling-index-delete.asciidoc[]
-include::indices/delete-index.asciidoc[]
 include::indices/delete-alias.asciidoc[]
+include::indices/delete-index.asciidoc[]
 include::indices/delete-index-template.asciidoc[]
 include::indices/delete-index-template-v1.asciidoc[]
 include::indices/indices-exists.asciidoc[]
 include::indices/flush.asciidoc[]
 include::indices/forcemerge.asciidoc[]
 include::indices/apis/freeze.asciidoc[]
+include::indices/get-alias.asciidoc[]
 include::indices/get-component-template.asciidoc[]
 include::indices/get-field-mapping.asciidoc[]
 include::indices/get-index.asciidoc[]
-include::indices/get-alias.asciidoc[]
 include::indices/get-settings.asciidoc[]
 include::indices/get-index-template.asciidoc[]
 include::indices/get-index-template-v1.asciidoc[]
 include::indices/get-mapping.asciidoc[]
 include::indices/dangling-index-import.asciidoc[]
-include::indices/alias-exists.asciidoc[]
 include::indices/recovery.asciidoc[]
 include::indices/segments.asciidoc[]
 include::indices/shard-stores.asciidoc[]

docs/reference/indices/add-alias.asciidoc

@@ -1,15 +1,10 @@
 [[indices-add-alias]]
-=== Create or update index alias API
+=== Create or update alias API
 ++++
-<titleabbrev>Create or update index alias</titleabbrev>
+<titleabbrev>Create or update alias</titleabbrev>
 ++++
 
-Creates or updates an index alias.
-
-//tag::index-alias-desc[]
-An index alias is a secondary name for one or more indices. Most {es} APIs
-accept an index alias in place of an index name.
-//end::index-alias-desc[]
+Adds a data stream or index to an <<alias,alias>>.
 
 [source,console]
 ----

docs/reference/indices/alias-exists.asciidoc

@@ -1,12 +1,10 @@
 [[indices-alias-exists]]
-=== Index alias exists API
+=== Alias exists API
 ++++
-<titleabbrev>Index alias exists</titleabbrev>
+<titleabbrev>Alias exists</titleabbrev>
 ++++
 
-Checks if an index alias exists.
-
-include::{es-repo-dir}/indices/add-alias.asciidoc[tag=index-alias-desc]
+Checks if an <<alias,alias>> exists.
 
 [source,console]
 ----

docs/reference/indices/aliases.asciidoc

@@ -4,11 +4,7 @@
 <titleabbrev>Aliases</titleabbrev>
 ++++
 
-Adds and removes multiple index aliases in a single request. Also deletes
-concrete indices.
-
-An index alias is a secondary name used to refer to one or more existing
-indices. Most {es} APIs accept an index alias in place of an index.
+Performs one or more <<alias,alias>> actions in a single atomic operation.
 
 [source,console]
 ----
@@ -121,7 +117,7 @@ If the `alias` parameter is not specified, this parameter is required for the
 (Optional, query object)
 include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=index-alias-filter]
 +
-See <<filtered>> for an example.
+See <<filter-alias>> for an example.
 
 `is_hidden`::
 (Optional, Boolean)
@@ -153,456 +149,19 @@ writes will be rejected.
 
 include::{es-repo-dir}/rest-api/common-parms.asciidoc[tag=routing]
 +
-See <<aliases-routing>> for an example.
+See <<alias-routing>> for an example.
 
 `index_routing`::
 (Optional, string)
 Custom <<mapping-routing-field, routing value>> used
 for the alias's indexing operations.
 +
-See <<aliases-routing>> for an example.
+See <<alias-routing>> for an example.
 
 `search_routing`::
 (Optional, string)
 Custom <<mapping-routing-field, routing value>> used
 for the alias's search operations.
 +
-See <<aliases-routing>> for an example.
+See <<alias-routing>> for an example.
 --
-
-
-[[indices-aliases-api-example]]
-==== {api-examples-title}
-
-[[indices-aliases-api-add-alias-ex]]
-===== Add an alias
-
-The following request adds the `alias1` alias to the `test1` index.
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions" : [
-    { "add" : { "index" : "test1", "alias" : "alias1" } }
-  ]
-}
---------------------------------------------------
-// TEST[s/^/PUT test1\nPUT test2\n/]
-
-Index alias names support <<date-math-index-names,date math>>.
-
-[source,console]
-----
-POST /_aliases
-{
-  "actions" : [
-    { "add" : { "index" : "logs", "alias" : "<logs_{now/M}>" } }
-  ]
-}
-----
-// TEST[s/^/PUT logs\n/]
-// TEST[continued]
-
-[[indices-aliases-api-remove-alias-ex]]
-===== Remove an alias
-
-The following request removes the `alias1` alias.
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions" : [
-    { "remove" : { "index" : "test1", "alias" : "alias1" } }
-  ]
-}
---------------------------------------------------
-// TEST[continued]
-
-[[indices-aliases-api-rename-alias-ex]]
-===== Rename an alias
-
-Renaming an alias is a simple `remove` then `add` operation within the
-same API. This operation is atomic, no need to worry about a short
-period of time where the alias does not point to an index:
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions" : [
-    { "remove" : { "index" : "test1", "alias" : "alias1" } },
-    { "add" : { "index" : "test1", "alias" : "alias2" } }
-  ]
-}
---------------------------------------------------
-// TEST[continued]
-
-[[indices-aliases-api-add-multi-alias-ex]]
-===== Add an alias to multiple indices
-
-Associating an alias with more than one index is simply several `add`
-actions:
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions" : [
-    { "add" : { "index" : "test1", "alias" : "alias1" } },
-    { "add" : { "index" : "test2", "alias" : "alias1" } }
-  ]
-}
---------------------------------------------------
-// TEST[s/^/PUT test1\nPUT test2\n/]
-
-Multiple indices can be specified for an action with the `indices` array syntax:
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions" : [
-    { "add" : { "indices" : ["test1", "test2"], "alias" : "alias1" } }
-  ]
-}
---------------------------------------------------
-// TEST[s/^/PUT test1\nPUT test2\n/]
-
-To specify multiple aliases in one action, the corresponding `aliases` array
-syntax exists as well.
-
-For the example above, a glob pattern can also be used to associate an alias to
-more than one index that share a common name:
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions" : [
-    { "add" : { "index" : "test*", "alias" : "all_test_indices" } }
-  ]
-}
---------------------------------------------------
-// TEST[s/^/PUT test1\nPUT test2\n/]
-
-In this case, the alias is a point-in-time alias that will group all
-current indices that match, it will not automatically update as new
-indices that match this pattern are added/removed.
-
-It is an error to index to an alias which points to more than one index.
-
-It is also possible to swap an index with an alias in one, atomic operation.
-This means there will be no point in time where the alias points to no
-index in the cluster state. However, as indexing and searches involve multiple
-steps, it is possible for the in-flight or queued requests to fail
-due to a temporarily non-existent index.
-
-[source,console]
---------------------------------------------------
-PUT test     <1>
-PUT test_2   <2>
-POST /_aliases
-{
-  "actions" : [
-    { "add":  { "index": "test_2", "alias": "test" } },
-    { "remove_index": { "index": "test" } }  <3>
-  ]
-}
---------------------------------------------------
-
-<1> An index we've added by mistake
-<2> The index we should have added
-<3> `remove_index` is just like <<indices-delete-index>> and will only remove a concrete index.
-
-[[filtered]]
-===== Filtered aliases
-
-Aliases with filters provide an easy way to create different "views" of
-the same index. The filter can be defined using Query DSL and is applied
-to all Search, Count, Delete By Query and More Like This operations with
-this alias.
-
-To create a filtered alias, first we need to ensure that the fields already
-exist in the mapping:
-
-[source,console]
---------------------------------------------------
-PUT /my-index-000001
-{
-  "mappings": {
-    "properties": {
-      "user": {
-        "properties": {
-          "id": {
-            "type": "keyword"
-          }
-        }
-      }
-    }
-  }
-}
---------------------------------------------------
-
-Now we can create an alias that uses a filter on field `user.id`:
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions": [
-    {
-      "add": {
-        "index": "my-index-000001",
-        "alias": "alias2",
-        "filter": { "term": { "user.id": "kimchy" } }
-      }
-    }
-  ]
-}
---------------------------------------------------
-// TEST[continued]
-
-[[aliases-routing]]
-===== Routing
-
-It is possible to associate routing values with aliases. This feature
-can be used together with filtering aliases in order to avoid
-unnecessary shard operations.
-
-The following command creates a new alias `alias1` that points to index
-`test`. After `alias1` is created, all operations with this alias are
-automatically modified to use value `1` for routing:
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions": [
-    {
-      "add": {
-        "index": "test",
-        "alias": "alias1",
-        "routing": "1"
-      }
-    }
-  ]
-}
---------------------------------------------------
-// TEST[s/^/PUT test\n/]
-
-It's also possible to specify different routing values for searching
-and indexing operations:
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions": [
-    {
-      "add": {
-        "index": "test",
-        "alias": "alias2",
-        "search_routing": "1,2",
-        "index_routing": "2"
-      }
-    }
-  ]
-}
---------------------------------------------------
-// TEST[s/^/PUT test\n/]
-
-As shown in the example above, search routing may contain several values
-separated by comma. Index routing can contain only a single value.
-
-If a search operation that uses routing alias also has a routing parameter, an
-intersection of both search alias routing and routing specified in the
-parameter is used. For example the following command will use "2" as a
-routing value:
-
-[source,console]
---------------------------------------------------
-GET /alias2/_search?q=user.id:kimchy&routing=2,3
---------------------------------------------------
-// TEST[continued]
-
-[[write-index]]
-===== Write index
-
-It is possible to associate the index pointed to by an alias as the write index.
-When specified, all index and update requests against an alias that point to multiple
-indices will attempt to resolve to the one index that is the write index.
-Only one index per alias can be assigned to be the write index at a time. If no write index is specified
-and there are multiple indices referenced by an alias, then writes will not be allowed.
-
-It is possible to specify an index associated with an alias as a write index using both the aliases API
-and index creation API.
-
-Setting an index to be the write index with an alias also affects how the alias is manipulated during
-Rollover (see <<indices-rollover-index, Rollover With Write Index>>).
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions": [
-    {
-      "add": {
-        "index": "test",
-        "alias": "alias1",
-        "is_write_index": true
-      }
-    },
-    {
-      "add": {
-        "index": "test2",
-        "alias": "alias1"
-      }
-    }
-  ]
-}
---------------------------------------------------
-// TEST[s/^/PUT test\nPUT test2\n/]
-
-In this example, we associate the alias `alias1` to both `test` and `test2`, where
-`test` will be the index chosen for writing to.
-
-[source,console]
---------------------------------------------------
-PUT /alias1/_doc/1
-{
-  "foo": "bar"
-}
---------------------------------------------------
-// TEST[continued]
-
-The new document that was indexed to `/alias1/_doc/1` will be indexed as if it were
-`/test/_doc/1`.
-
-[source,console]
---------------------------------------------------
-GET /test/_doc/1
---------------------------------------------------
-// TEST[continued]
-
-To swap which index is the write index for an alias, the Aliases API can be leveraged to
-do an atomic swap. The swap is not dependent on the ordering of the actions.
-
-[source,console]
---------------------------------------------------
-POST /_aliases
-{
-  "actions": [
-    {
-      "add": {
-        "index": "test",
-        "alias": "alias1",
-        "is_write_index": false
-      }
-    }, {
-      "add": {
-        "index": "test2",
-        "alias": "alias1",
-        "is_write_index": true
-      }
-    }
-  ]
-}
---------------------------------------------------
-// TEST[s/^/PUT test\nPUT test2\n/]
-
-[[aliases-data-streams]]
-===== Data stream aliases
-
-An alias can also point to one or more data streams. To add a data stream to an
-alias, specify the stream's name in the `index` parameter. Wildcards (`*`) are
-supported. If a wildcard pattern matches both data streams and indices, the
-action only uses the matching data streams.
-
-You can only specify data streams in the `add` and `remove` actions. Aliases
-that point to data streams do not support the following parameters:
-
-* `filter`
-* `index_routing`
-* `is_write_index`
-* `routing`
-* `search_routing`
-
-For example, the following request adds two data streams to the `logs` alias.
-
-////
-[source,console]
-----
-PUT _data_stream/logs-my_app-default
-
-PUT _data_stream/logs-nginx.access-prod
-----
-////
-
-[source,console]
-----
-POST _aliases
-{
-  "actions": [
-    { "add": { "index": "logs-my_app-default", "alias": "logs" }},
-    { "add": { "index": "logs-nginx.access-prod", "alias": "logs" }}
-  ]
-}
-----
-// TEST[continued]
-
-To verify the alias points to both data streams, use the
-<<indices-get-alias,get index alias API>>.
-
-[source,console]
-----
-GET logs-*/_alias
-----
-// TEST[continued]
-
-The API returns:
-
-[source,console-result]
-----
-{
-  "logs-my_app-default": {
-    "aliases": {
-      "logs": {}
-    }
-  },
-  "logs-nginx.access-prod": {
-    "aliases": {
-      "logs": {}
-    }
-  }
-}
-----
-
-Use the `remove` action to remove a data stream from an alias.
-
-[source,console]
-----
-POST _aliases
-{
-  "actions": [
-    { "remove": { "index": "logs-my_app-default", "alias": "logs" }}
-  ]
-}
-
-GET logs-*/_alias
-----
-// TEST[continued]
-
-The get index alias API returns:
-
-[source,console-result]
-----
-{
-  "logs-nginx.access-prod": {
-    "aliases": {
-      "logs": {}
-    }
-  }
-}
-----

docs/reference/indices/delete-alias.asciidoc

@@ -1,12 +1,10 @@
 [[indices-delete-alias]]
-=== Delete index alias API
+=== Delete alias API
 ++++
-<titleabbrev>Delete index alias</titleabbrev>
+<titleabbrev>Delete alias</titleabbrev>
 ++++
 
-Deletes an existing index alias.
-
-include::{es-repo-dir}/indices/add-alias.asciidoc[tag=index-alias-desc]
+Deletes an <<alias,alias>>.
 
 [source,console]
 ----

docs/reference/indices/get-alias.asciidoc

@@ -1,12 +1,10 @@
 [[indices-get-alias]]
-=== Get index alias API
+=== Get alias API
 ++++
-<titleabbrev>Get index alias</titleabbrev>
+<titleabbrev>Get alias</titleabbrev>
 ++++
 
-Returns information about one or more index aliases.
-
-include::{es-repo-dir}/indices/add-alias.asciidoc[tag=index-alias-desc]
+Retrieves information for one or more <<alias,aliases>>.
 
 [source,console]
 ----

docs/reference/indices/migrate-to-data-stream.asciidoc

@@ -90,8 +90,8 @@ following criteria:
 
 - The alias must have a <<write-index,write index>>.
 - All indices for the alias have a `@timestamp` field mapping of a `date` or `date_nanos` field type.
-- The alias must not have any <<filtered,filters>>.
-- The alias must not use <<aliases-routing,custom routing>>.
+- The alias must not have any <<filter-alias,filters>>.
+- The alias must not use <<alias-routing,custom routing>>.
 
 If successful, the request removes the alias and creates a data stream with the
 same name. The alias's indices become hidden backing indices for the stream. The