Creating a Snapshot to Back Up the Data of an Elasticsearch Cluster

Constraints

• Snapshots cannot be created for clusters that were created before March 10, 2018.
• Cluster snapshots will increase CPU usage and disk I/O. You are advised to take cluster snapshots during off-peak hours.
• If a cluster is in the Unavailable state, you can use the cluster snapshot function only to restore the cluster or view snapshot information.
• While you are creating a snapshot for a cluster or restoring it using one, you can perform certain operations, including scaling out the cluster (except when the cluster is the destination of a restoration operation), accessing Kibana, viewing metrics, and deleting other snapshots. However, you cannot perform the following operations: restarting or deleting the cluster, deleting a snapshot that is in the Creating or Restoring state, and creating or restoring another snapshot. While a snapshot is being created or restored for a cluster, any automatic snapshot creation task initiated for that cluster will be canceled.
• The first snapshot of a cluster is a full snapshot, and subsequent snapshots are incremental snapshots. CSS snapshot files depend on each other.
• In a cluster where storage and compute are decoupled, an index that is both frozen and closed cannot be backed up.

Prerequisites

• You have created an OBS bucket for storing snapshots. Storing snapshots in an OBS bucket may incur additional fees. For details, see OBS Billing Overview.

Setting Automatic Snapshot Creation

1. Log in to the CSS management console.
2. Enable automatic snapshot creation for a cluster. You can enable automatic snapshot creation when creating a new cluster. For details, see 7. Alternatively, you can do that for an existing cluster.
   • If automatic snapshot creation has been enabled during cluster creation, go to 7.
   • To enable automatic snapshot creation after a cluster is already created, go to the next step.
3. On the Clusters page, click the name of the target cluster. In the navigation pane on the left, choose Cluster Snapshots.

   Alternatively, on the Clusters page, locate the row that contains the target cluster and click More > Back Up and Restore in the Operation column to switch to the Cluster Snapshots page.

4. On the displayed Cluster Snapshots page, click the icon to the right of Cluster Snapshot to enable the cluster snapshot function. If it is already enabled, skip this step.

   CSS will automatically create an OBS bucket and IAM agency for snapshot storage. The automatically created OBS bucket and IAM agency will be displayed on the page.

   To modify them, click on the right of Basic Configuration to edit the configuration. After the OBS bucket is changed, the cluster obtains snapshot data from the new bucket.

   Table 1 Basic configuration for a cluster snapshot policy

   Parameter	Description
   OBS Bucket	Select an OBS bucket for storing snapshots from the drop-down list box. You can also click Create Bucket on the right to create an OBS bucket. For details, see Creating a Bucket. The created or existing OBS bucket must meet the following requirements: Storage Class is Standard. Region must be the same as that of the created cluster.
   Backup Path	Storage path of the snapshot in the OBS bucket. The backup path cannot: Contain the following characters: \:*?"<>| Start with a slash (/). Start or end with a period (.). Exceed 1023 characters.
   IAM Agency	To store snapshot data to an OBS bucket, you must have the required OBS access permissions. Select an IAM agency to grant the current account the permission to access and use OBS. If you are configuring an agency for the first time, click Automatically Create IAM Agency to create css-obs-agency. If there is an IAM agency automatically created earlier, you can click One-click authorization to delete the OBS Administrator permissions, and add the following custom policies instead to implement more refined permissions control. "obs:bucket:GetBucketLocation", "obs:object:GetObjectVersion", "obs:object:GetObject", "obs:object:DeleteObject", "obs:bucket:HeadBucket", "obs:bucket:GetBucketStoragePolicy", "obs:object:DeleteObjectVersion", "obs:bucket:ListBucketVersions", "obs:bucket:ListBucket", "obs:object:PutObject" To use Automatically Create IAM Agency and One-click authorization, the following minimum permissions are needed: "iam:agencies:listAgencies", "iam:roles:listRoles", "iam:agencies:getAgency", "iam:agencies:createAgency", "iam:permissions:listRolesForAgency", "iam:permissions:grantRoleToAgency", "iam:permissions:listRolesForAgencyOnProject", "iam:permissions:revokeRoleFromAgency", "iam:roles:createRole" To use an IAM agency, the following minimum permissions are needed: "iam:agencies:listAgencies", "iam:agencies:getAgency", "iam:permissions:listRolesForAgencyOnProject", "iam:permissions:listRolesForAgency"

5. Enable the automatic snapshot creation function. The Configure Automatic Snapshot Creation dialog box is displayed. If the automatic snapshot creation function is enabled, you can click on the right of Automatic Snapshot Creation to modify the snapshot policy.

   Table 2 Setting automatic snapshot creation

   Parameter	Description
   Snapshot Name Prefix	The snapshot name prefix contains 1 to 32 characters and must start with a lowercase letter. Only lowercase letters, digits, hyphens (-), and underscores (_) are allowed. A snapshot name consists of a snapshot name prefix and a timestamp, for example, snapshot-1566921603720.
   Time Zone	Time zone for the backup time, which cannot be changed. Specify Backup Started Time based on the time zone.
   Backup Start Time	The time when the backup starts automatically every day. You can specify this parameter only in full hours, for example, 00:00 or 01:00. The value ranges from 00:00 to 23:00. Select a time from the drop-down list.
   Retained Snapshots	Number of automatic snapshots to be retained. The value ranges from 1 to 90. The system automatically deletes excess snapshots every half hour. (The expiration deletion policy applies only to the snapshots that were automatically created at the same frequency as the current automatic snapshot creation policy.) NOTE: If the snapshot creation interval is short or if the data size of indexes is large, the number of automatic snapshots retained may not reach the value set using this parameter.
   Index	Indexes that you want to back up using snapshots. The index names cannot contain spaces or uppercase letters, and cannot contain "\<|>/?. Use commas (,) to separate different index names. If you do not specify this parameter, all indexes in the cluster are backed up by default. You can use the asterisk (*) to match multiple indexes. For example, if you enter index*, then the data of all indexes whose names are prefixed with index will be backed up. NOTE: Run the GET /_cat/indices command in Kibana to query the names of all indexes in the cluster.

   Figure 1 Configure Automatic Snapshot Creation
   
6. To apply an automatic snapshot policy, enter CONFIRM in the text box.Click OK to save the snapshot policy.
7. Snapshots that are automatically created according to the snapshot policy are displayed in the snapshot list, along with manually created snapshots. You can distinguish between them based on Snapshot Type. In the upper right corner of the snapshot list, enter the keyword of the snapshot name or snapshot ID to search for the desired snapshots.
   

   If snapshot creation fails, click on the right of the snapshot list to view the number of failed tasks and learn the failure causes. A maximum of 20 failed tasks can be displayed. When the snapshot function is disabled or the cluster is deleted, the failure records are also cleared.

8. (Optional) Disable the automatic snapshot creation function.

   After you disable the automatic snapshot creation function, the system stops automatic creation of snapshots. If the system is creating a snapshot based on the automatic snapshot creation policy and the snapshot is not yet displayed in the snapshot list, you cannot disable the automatic snapshot creation function. In this case, if you click the button next to Automatic Snapshot Creation, a message is displayed, indicating that you cannot disable the function. You are advised to disable the function after the system completes automatic creation of the snapshot, and the created snapshot is displayed in the snapshot list.

   When disabling the automatic snapshot creation function, you can choose whether to delete the snapshots that have been automatically created by selecting Delete automated snapshots in the displayed dialog box. By default, automatically created snapshots are not deleted.

   • If you do not select Delete automated snapshots, automatically created snapshots are not deleted when you disable the automatic snapshot creation function. You can manually delete them later. For details, see Deleting an Elasticsearch Cluster Snapshot. If you do not manually delete the automatically created snapshots and enable the automatic snapshot creation function again, then all snapshots with Snapshot Type set to Automated in the snapshot list of the cluster can only be automatically deleted by the system. The system automatically deletes snapshots based on the policy configured when the automatic snapshot creation function is enabled. For example, if the number of retained snapshots is set to 10 in this policy and more than 10 snapshots are created, the system automatically deletes the excess snapshots on the half hour.
   • If you select Delete automated snapshots, all snapshots with Snapshot Type set to Automated in the snapshot list will be deleted when you disable the automatic snapshot creation function.
   

   If snapshots are disabled, existing snapshots will not be automatically deleted. If you need to delete the snapshots, manage the bucket that stores snapshots on the OBS console.

Manually Creating a Snapshot

1. Log in to the CSS management console.
2. On the Clusters page, click the name of the target cluster. In the navigation pane on the left, choose Cluster Snapshots.

   Alternatively, on the Clusters page, locate the row that contains the target cluster and click More > Back Up and Restore in the Operation column to switch to the Cluster Snapshots page.

3. On the displayed Cluster Snapshots page, click the icon to the right of Cluster Snapshot to enable the cluster snapshot function. If it is already enabled, skip this step.

   CSS will automatically create an OBS bucket and IAM agency for snapshot storage. The automatically created OBS bucket and IAM agency will be displayed on the page.

   To modify them, click on the right of Basic Configuration to edit the configuration. After the OBS bucket is changed, the cluster obtains snapshot data from the new bucket.

   Table 3 Basic configuration for a cluster snapshot policy

   Parameter	Description
   OBS Bucket	Select an OBS bucket for storing snapshots from the drop-down list box. You can also click Create Bucket on the right to create an OBS bucket. For details, see Creating a Bucket. The created or existing OBS bucket must meet the following requirements: Storage Class is Standard. Region must be the same as that of the created cluster.
   Backup Path	Storage path of the snapshot in the OBS bucket. The backup path cannot: Contain the following characters: \:*?"<>| Start with a slash (/). Start or end with a period (.). Exceed 1023 characters.
   IAM Agency	To store snapshot data to an OBS bucket, you must have the required OBS access permissions. Select an IAM agency to grant the current account the permission to access and use OBS. If you are configuring an agency for the first time, click Automatically Create IAM Agency to create css-obs-agency. If there is an IAM agency automatically created earlier, you can click One-click authorization to delete the OBS Administrator permissions, and add the following custom policies instead to implement more refined permissions control. "obs:bucket:GetBucketLocation", "obs:object:GetObjectVersion", "obs:object:GetObject", "obs:object:DeleteObject", "obs:bucket:HeadBucket", "obs:bucket:GetBucketStoragePolicy", "obs:object:DeleteObjectVersion", "obs:bucket:ListBucketVersions", "obs:bucket:ListBucket", "obs:object:PutObject" To use Automatically Create IAM Agency and One-click authorization, the following minimum permissions are needed: "iam:agencies:listAgencies", "iam:roles:listRoles", "iam:agencies:getAgency", "iam:agencies:createAgency", "iam:permissions:listRolesForAgency", "iam:permissions:grantRoleToAgency", "iam:permissions:listRolesForAgencyOnProject", "iam:permissions:revokeRoleFromAgency", "iam:roles:createRole" To use an IAM agency, the following minimum permissions are needed: "iam:agencies:listAgencies", "iam:agencies:getAgency", "iam:permissions:listRolesForAgencyOnProject", "iam:permissions:listRolesForAgency"

4. After basic configurations are completed, click Create to manually create a snapshot.

   Table 4 Parameters for manually creating a snapshot

   Parameter	Description
   Snapshot Name	Name of a manually created snapshot. It can contain 4 to 64 characters and must start with a lowercase letter. Only lowercase letters, digits, hyphens (-), and underscores (_) are allowed. For snapshots you create manually, you can specify the snapshot name. The system will not automatically add a timestamp to the snapshot name.
   Index	Indexes that you want to back up using snapshots. The index names cannot contain spaces or uppercase letters, and cannot contain "\<|>/?. Use commas (,) to separate different index names. If you do not specify this parameter, all indexes in the cluster are backed up by default. You can use the asterisk (*) to match multiple indexes. For example, if you enter index*, then the data of all indexes whose names are prefixed with index will be backed up. NOTE: Run the GET /_cat/indices command in Kibana to query the names of all indexes in the cluster.
   Description	Description of the snapshot. The value contains 0 to 256 characters and cannot contain <>.

   Figure 2 Manually creating a snapshot
   
5. Click OK to create the snapshot.

   After the snapshot is created, it is displayed in the snapshot list. The status Available indicates that the snapshot is created successfully. along with manually created snapshots. You can distinguish them by the Snapshot Type setting. In the upper right corner of the snapshot list, enter the keyword of the snapshot name or snapshot ID to search for the desired snapshots.

   

   If snapshot creation fails, click on the right of the snapshot list to view the number of failed tasks and learn the failure causes. A maximum of 20 failed tasks can be displayed. When the snapshot function is disabled or the cluster is deleted, the failure records are also cleared.