Elasticsearch:Automatic backup and restoration

Background information

Data backup and restoration for ES instances rely on the elasticsearch-repository-oss plugin. This plugin is installed on Alibaba Cloud ES instances by default and cannot be uninstalled. For more information, see elasticsearch-repository-oss.

Precautions

• The size of index metadata for an automatic backup cannot exceed 100 MB. If this limit is exceeded, the automatic backup task may fail. In this case, perform a manual backup.

• The first snapshot of a cluster is a full copy of the cluster data. Subsequent snapshots synchronize only the incremental data from the previous snapshot. The first snapshot is usually large and takes a long time to create. To prevent synchronization failures, perform a manual backup for the first snapshot.

• Snapshots save only index data. They do not save the ES instance's monitoring data, such as indexes prefixed with .monitoring and .security_audit. They also do not save metadata, Translogs, instance configurations, ES software packages, built-in and custom plugins, or ES logs.

• Automatic backups only retain snapshot data from the last seven days. The snapshots contain full data.

• Data from automatic backups can only be restored to the original cluster. To restore data across clusters, see Manual backup and restoration or Set up a cross-cluster OSS repository.

• When you disable automatic backup, the system performs one final data backup. Updating the automatic backup start time does not trigger a data backup.

• For OpenStore Indexing Service instances, the underlying storage service ensures high availability (HA) of cluster data. Therefore, the automatic backup feature is not supported.

Enable automatic backup and monitoring alarms

View backup snapshots

After you enable the automatic backup feature, you can log on to the Kibana console. On the Kibana console of the corresponding Alibaba Cloud Elasticsearch instance, use the _snapshot API to view information about automatic backup snapshots:

• View the snapshot repository.

  GET _snapshot

  A successful request returns a response similar to the following example.

  {
    "aliyun_auto_snapshot" : {
      "type" : "oss",
      "settings" : {
        "compress" : "true",
        "base_path" : "cf95b9-185320276651****/es-cn-09k2053us0003****",
        "endpoint" : "http://oss-cn-hangzhou-internal.aliyuncs.com"
      }
    }
  }
                              

  Parameter	Description
  aliyun_auto_snapshot	The automatic snapshot repository is created when the first snapshot is taken. The name of the repository that stores automatic backup snapshots for Alibaba Cloud Elasticsearch is fixed as aliyun_auto_snapshot. Note A repository can store multiple snapshots. Each snapshot can contain the backup data of all, some, or a single index.
  type	The storage medium for snapshots. oss indicates that the storage medium is Object Storage Service (OSS).
  compress	Specifies whether to enable compression for snapshot files: true: Enables compression. This applies only to metadata files, which include index mappings and settings. false (default): Disables compression. Data files are not compressed.
  base_path	The storage location of the snapshot in OSS.
  endpoint	Information about the region where OSS is located.

• View information about all snapshots in the aliyun_auto_snapshot repository.

  GET _snapshot/aliyun_auto_snapshot/_all

  A successful request returns a response similar to the following example.

  {
    "snapshots": [
      {
        "snapshot": "es-cn-09k2053us0003****_20210117030003",
        "uuid": "vIdSCkthTeGa0nSj4D****",
        "version_id": 5050399,
        "version": "5.5.3",
        "indices": [
          ".kibana"
        ],
        "state": "SUCCESS",
        "start_time": "2018-06-28T01:22:39.609Z",
        "start_time_in_millis": 1530148959609,
        "end_time": "2018-06-28T01:22:39.923Z",
        "end_time_in_millis": 1530148959923,
        "duration_in_millis": 314,
        "failures": [],
        "shards": {
          "total": 1,
          "failed": 0,
          "successful": 1
        }
      },
      {
        "snapshot": "es-cn-09k2053us0003****_20210118030004",
        "uuid": "XKO_Uwz_Qu6mZrU3Am****",
        "version_id": 5050399,
        "version": "5.5.3",
        "indices": [
          ".kibana"
        ],
        "state": "SUCCESS",
        "start_time": "2018-06-28T01:25:00.764Z",
        "start_time_in_millis": 1530149100764,
        "end_time": "2018-06-28T01:25:01.482Z",
        "end_time_in_millis": 1530149101482,
        "duration_in_millis": 718,
        "failures": [],
        "shards": {
          "total": 1,
          "failed": 0,
          "successful": 1
        }
      }
    ]
  }

  Important

  The backup time is in the local time of the region where the instance resides. However, the time in the returned response is in Coordinated Universal Time (UTC). A time zone difference exists between the two. You can convert the time based on this difference. For example, the time zone difference for UTC+8 is 8 hours. Therefore, UTC+8 = UTC + 0800.

  The state parameter indicates the snapshot status. Snapshots for an Alibaba Cloud Elasticsearch instance can have one of the following five statuses.

  Snapshot status	Description
  IN_PROGRESS	The snapshot is in progress.
  SUCCESS	The snapshot process is complete, and all data from all shards is successfully stored.
  FAILED	The snapshot process is complete, but data from some indexes was not successfully stored.
  PARTIAL	Some data was stored successfully, but data from at least one shard was not stored.
  INCOMPATIBLE	The snapshot is incompatible with the version of the Alibaba Cloud Elasticsearch instance.

  Automatic backup snapshots also have the following default parameters that are not displayed.

  Parameter	Description
  max_snapshot_bytes_per_sec	The maximum speed for data backup on a single node. The default value is 40mb per second.
  max_restore_bytes_per_sec	The maximum speed for data restoration on a single node. The default value is 40mb per second.
  chunk_size	When creating a snapshot, large files are split into smaller chunks. This parameter sets the size of the chunks, such as 1g, 10m, or 5k. The default value is null, which means there is no limit.

• View detailed information about a specific snapshot in the aliyun_auto_snapshot repository.

  GET _snapshot/aliyun_auto_snapshot/<snapshot>/_status

  <snapshot>: The name of the automatic backup snapshot. You can retrieve this name by running the command to view all snapshots. For example: es-cn-09k2053us0003****_20210118030004.

  A successful request returns a response similar to the following example.

  {
    "snapshots": [
      {
        "snapshot": "es-cn-09k2053us0003****_20210118030004",
        "repository": "aliyun_auto_snapshot",
        "uuid": "XKO_Uwz_Qu6mZrU3Am****",
        "state": "SUCCESS",
        "shards_stats": {
          "initializing": 0,
          "started": 0,
          "finalizing": 0,
          "done": 1,
          "failed": 0,
          "total": 1
        },
        "stats": {
          "number_of_files": 4,
          "processed_files": 4,
          "total_size_in_bytes": 3296,
          "processed_size_in_bytes": 3296,
          "start_time_in_millis": 1530148959688,
          "time_in_millis": 77
        },
        "indices": {
          ".kibana": {
            "shards_stats": {
              "initializing": 0,
              "started": 0,
              "finalizing": 0,
              "done": 1,
              "failed": 0,
              "total": 1
            },
            "stats": {
              "number_of_files": 4,
              "processed_files": 4,
              "total_size_in_bytes": 3296,
              "processed_size_in_bytes": 3296,
              "start_time_in_millis": 1530148959688,
              "time_in_millis": 77
            },
            "shards": {
              "0": {
                "stage": "DONE",
                "stats": {
                  "number_of_files": 4,
                  "processed_files": 4,
                  "total_size_in_bytes": 3296,
                  "processed_size_in_bytes": 3296,
                  "start_time_in_millis": 1530148959688,
                  "time_in_millis": 77
                }
              }
            }
          }
        }
      }
    ]
  }

Restore data from an automatic backup

Disable automatic backup

1. Log on to the Alibaba Cloud Elasticsearch console.

2. In the left-side navigation pane, click Elasticsearch Clusters.

3. Navigate to the desired cluster.

   1. In the top navigation bar, select the resource group to which the cluster belongs and the region where the cluster resides.

   2. On the Elasticsearch Clusters page, find the cluster and click its ID.

4. In the navigation pane on the left, click Data Backup.

5. In the Snapshots (Free Trial) section, turn off Auto Snapshot.

References

• Manual backup and restoration

• Automatically back up snapshots to a local OSS repository

• Log on to the Kibana console