Adds snapshot restore documentation (#1822)

* Adds snapshot restore documentation

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

* Adds snapshot restore in dashboards documentation

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

* Adds snapshot restore in Dashboards documentation

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

* Added description of custom index settings and ignore unavailable

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

* Clarification and image change

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

* Implemented editorial feedback

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

* More editorial feedback

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

* Reworded a sentence

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

Signed-off-by: Fanit Kolchina <kolchfa@amazon.com>

_opensearch/snapshots/sm-dashboards.md

@@ -82,7 +82,7 @@ All automatically or manually taken snapshots appear in the list.
 
 ## Take a snapshot
 
-Use the steps below to take a snapshot manually. If you need to restore a snapshot, use the [restore snapshot API operation]({{site.url}}{{site.baseurl}}/opensearch/snapshots/snapshot-restore#restore-snapshots).
+Use the steps below to take a snapshot manually:
 
 1. On the top menu bar, go to **OpenSearch Plugins > Snapshot Management**.
 1. In the left panel, under **Snapshot Management**, select **Snapshots**.
@@ -95,3 +95,55 @@ Use the steps below to take a snapshot manually. If you need to restore a snapsh
     - **Ignore unavailable indices**
     - **Allow partial snapshots**
 1. Select the **Add** button.
+
+## Restore a snapshot
+
+1. On the top menu bar, go to **OpenSearch Plugins > Snapshot Management**.
+1. In the left panel, under **Snapshot Management**, select **Snapshots**. The **Snapshots** tab is selected by default.
+1. Select the checkbox next to the snapshot you want to restore, as shown in the following image: 
+    <img src="{{site.url}}{{site.baseurl}}/images/restore-snapshot/restore-snapshot-main.png" alt="Snapshots">{: .img-fluid}
+
+    You can only restore snapshots with the status of `Success` or `Partial`. The status of the snapshot is displayed in the **Snapshot status** column.
+    {: .note}
+1. In the **Restore snapshot** flyout, select the options for restoring the snapshot.
+
+    The **Restore snapshot** flyout lists the snapshot name and status. To view the list of indexes in the snapshot, select the number under **Indices** (for example, `27` in the following image). This number represents the number of indexes in the snapshot.
+
+    <img src="{{site.url}}{{site.baseurl}}/images/restore-snapshot/restore-snapshot.png" alt="Restore Snapshot" width="450">
+
+    For more information about the options in the **Restore snapshot** flyout, see [Restore snapshots]({{site.url}}{{site.baseurl}}/opensearch/snapshots/snapshot-restore#restore-snapshots). 
+
+    **Ignoring missing indexes**
+
+    If you specify which indexes you want to restore from the snapshot and select the **Ignore unavailable indices** option, the restore operation ignores the indexes that are missing from the snapshot. For example, if you want to restore the `log1` and `log2` indexes, but `log2` is not in the snapshot, `log1` is restored and `log2` is ignored. If you don't select **Ignore unavailable indices**, the entire restore operation fails if an index to be restored is missing from a snapshot.
+
+    **Custom index settings**
+
+    You can choose to customize some settings for the indexes restored from a snapshot:<br>
+        &emsp;&#x2022; Select the **Customize index settings** checkbox to provide new values for the specified index settings. All newly restored indexes will use these values instead of the ones in the snapshot. <br>
+        &emsp;&#x2022; Select the **Ignore index settings** checkbox to specify the settings in the snapshot to ignore. All newly restored indexes will use the cluster defaults for these settings.
+
+    The examples in the following image set `index.number_of_replicas` to `0`, `index.auto_expand_replicas` to `true`, and `index.refresh_interval` and `index.max_script_fields` to the cluster default values for all newly restored indexes. 
+
+    <img src="{{site.url}}{{site.baseurl}}/images/restore-snapshot/restore-snapshot-custom.png" alt="Custom settings" width="450">
+
+    For more information about index settings, see [Index settings]({{site.url}}{{site.baseurl}}/api-reference/index-apis/create-index/#index-settings).
+
+    For a list of settings that you cannot change or ignore, see [Restore snapshots]({{site.url}}{{site.baseurl}}/opensearch/snapshots/snapshot-restore#restore-snapshots).
+    
+    After choosing the options, select the **Restore snapshot** button.
+1. (Optional) To monitor the restore progress, select **View restore activities** in the confirmation dialog. You can also monitor the restore progress at any time by selecting the **Restore activities in progress** tab, as shown in the following image. 
+
+    <img src="{{site.url}}{{site.baseurl}}/images/restore-snapshot/restore-snapshot-activities.png" alt="Restore Activities">{: .img-fluid}
+
+    You can view the percentage of the job that has been completed in the **Status** column. Once the snapshot restore is complete, the **Status** changes to `Completed (100%)`. 
+
+    The **Restore activities in progress** panel is not persistent. It displays only the progress of the current restore operation. If multiple restore operations are running, the panel displays the most recent one.
+    {: .note }
+    To view the status of each index being restored, select the link in the **Indices being restored** column (in the preceding image, the `27 Indices` link). The **Indices being restored** flyout (shown in the following image) displays each index and its restore status.
+
+    <img src="{{site.url}}{{site.baseurl}}/images/restore-snapshot/restore-snapshot-indices.png" alt="Restore Indices">{: .img-fluid}
+
+ After the restore operation is complete, the restored indexes are listed in the **Indices** panel. To view the indexes, in the left panel, under **Index Management**, select **Indices**.
+
+<img src="{{site.url}}{{site.baseurl}}/images/restore-snapshot/restore-snapshot-indices-panel.png" alt="View Indices">{: .img-fluid}

_opensearch/snapshots/snapshot-restore.md

@@ -341,9 +341,9 @@ Request fields | Description
 `partial` | Whether to allow the restoration of partial snapshots. Default is false.
 `rename_pattern` | If you want to rename indices as you restore them, use this option to specify a regular expression that matches all indices you want to restore. Use capture groups (`()`) to reuse portions of the index name.
 `rename_replacement` | If you want to rename indices as you restore them, use this option to specify the replacement pattern. Use `$0` to include the entire matching index name, `$1` to include the content of the first capture group, etc.
-`index_settings` | If you want to change index settings on restore, specify them here.
-`ignore_index_settings` | Rather than explicitly specifying new settings with `index_settings`, you can ignore certain index settings in the snapshot and use the cluster defaults on restore.
-
+`index_settings` | If you want to change [index settings]({{site.url}}{{site.baseurl}}/api-reference/index-apis/create-index/#index-settings) applied during restore, specify them here. You cannot change `index.number_of_shards`.
+`ignore_index_settings` | Rather than explicitly specifying new settings with `index_settings`, you can ignore certain index settings in the snapshot and use the cluster defaults applied during restore. You cannot ignore `index.number_of_shards`, `index.number_of_replicas`, or `index.auto_expand_replicas`.
+`storage_type` | `local` indicates that all snapshot metadata and index data will be downloaded to local storage. <br /><br > `remote_snapshot` indicates that snapshot metadata will be downloaded to the cluster, but the remote repository will remain the authoritative store of the index data. Data will be downloaded and cached as necessary to service queries. At least one node in the cluster must be configured with the [search role]({{site.url}}{{site.baseurl}}/security-plugin/access-control/users-roles/) in order to restore a snapshot using the type `remote_snapshot`. <br /><br > Defaults to `local`.
 
 ### Conflicts and compatibility