Change the default of `include_global_state` from true to false for restores

This changes the default value to be false *only* for restore operations.

Resolves #18569

core/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/restore/RestoreSnapshotRequest.java

@@ -57,7 +57,7 @@ public class RestoreSnapshotRequest extends MasterNodeRequest<RestoreSnapshotReq
     private String renamePattern;
     private String renameReplacement;
     private boolean waitForCompletion;
-    private boolean includeGlobalState = true;
+    private boolean includeGlobalState = false;
     private boolean partial = false;
     private boolean includeAliases = true;
     private Settings settings = EMPTY_SETTINGS;

docs/reference/migration/migrate_5_0/settings.asciidoc

@@ -277,3 +277,9 @@ should be used instead.
 
 The setting `bootstrap.mlockall` has been renamed to
 `bootstrap.memory_lock`.
+
+==== Snapshot settings
+
+The default setting `include_global_state` for restoring snapshots has been
+changed from `true` to `false`. It has not been changed for taking snapshots and
+still defaults to `true` in that case.

docs/reference/modules/snapshots.asciidoc

@@ -323,13 +323,17 @@ POST /_snapshot/my_backup/snapshot_1/_restore
 -----------------------------------
 // CONSOLE
 
-By default, all indices in the snapshot as well as cluster state are restored. It's possible to select indices that
-should be restored as well as prevent global cluster state from being restored by using `indices` and
-`include_global_state` options in the restore request body. The list of indices supports
-<<search-multi-index-type,multi index syntax>>. The `rename_pattern` and `rename_replacement` options can be also used to
-rename index on restore using regular expression that supports referencing the original text as explained
+By default, all indices in the snapshot are restored, and the cluster state is
+*not* restored. It's possible to select indices that should be restored as well
+as to allow the global cluster state from being restored by using `indices` and
+`include_global_state` options in the restore request body. The list of indices
+supports <<search-multi-index-type,multi index syntax>>. The `rename_pattern`
+and `rename_replacement` options can be also used to rename index on restore
+using regular expression that supports referencing the original text as
+explained
 http://docs.oracle.com/javase/6/docs/api/java/util/regex/Matcher.html#appendReplacement(java.lang.StringBuffer,%20java.lang.String)[here].
-Set `include_aliases` to `false` to prevent aliases from being restored together with associated indices
+Set `include_aliases` to `false` to prevent aliases from being restored together
+with associated indices
 
 [source,js]
 -----------------------------------
@@ -337,19 +341,22 @@ POST /_snapshot/my_backup/snapshot_1/_restore
 {
   "indices": "index_1,index_2",
   "ignore_unavailable": "true",
-  "include_global_state": false,
+  "include_global_state": true,
   "rename_pattern": "index_(.+)",
   "rename_replacement": "restored_index_$1"
 }
 -----------------------------------
 // CONSOLE
 
-The restore operation can be performed on a functioning cluster. However, an existing index can be only restored if it's
-<<indices-open-close,closed>> and has the same number of shards as the index in the snapshot.
-The restore operation automatically opens restored indices if they were closed and creates new indices if they
-didn't exist in the cluster. If cluster state is restored, the restored templates that don't currently exist in the
-cluster are added and existing templates with the same name are replaced by the restored templates. The restored
-persistent settings are added to the existing persistent settings.
+The restore operation can be performed on a functioning cluster. However, an
+existing index can be only restored if it's <<indices-open-close,closed>> and
+has the same number of shards as the index in the snapshot. The restore
+operation automatically opens restored indices if they were closed and creates
+new indices if they didn't exist in the cluster. If cluster state is restored
+with `include_cluster_state` (defaults to `false`), the restored templates that
+don't currently exist in the cluster are added and existing templates with the
+same name are replaced by the restored templates. The restored persistent
+settings are added to the existing persistent settings.
 
 [float]
 ==== Partial restore