Updated on 2026-09-02 GMT+08:00

Changing AZs for a Cluster Instance

Function

An availability zone (AZ) is a physical region where resources use independent power supplies and networks. AZs in the same region can communicate with each other through internal networks but are physically isolated.

Multi-AZ deployment is a high-availability solution provided by CSS. You can deploy a cluster across two or three AZs in the same region. This helps prevent data loss and lower the risk of downtime.

This API is used to change AZs for an Elasticsearch or OpenSearch cluster by specifying node types.

Constraints

To ensure service continuity, the total number of data nodes and cold data nodes in the cluster must be greater than or equal to 3.
To ensure that all index shards in the cluster can be allocated to the remaining data nodes or cold data nodes, and to prevent replicas from becoming unassignable when nodes go offline during switchover, the total number of data nodes and cold data nodes must be greater than the maximum number of index replicas plus 1.
In AZ high-availability reconstruction scenarios, when converting from a single-AZ deployment to a dual-AZ deployment, the final number of data nodes or cold data nodes in each AZ must be no fewer than 2.
During the switchover process, nodes are taken offline and rebuilt one by one. You must ensure that after any single node goes offline, the remaining nodes have enough disk capacity to accommodate all data from that node, and that disk usage remains below 80%.
While the cluster is switching AZs, the AZ attribute of some nodes may already have changed. In this case, the displayed AZ of the nodes may show an intermediate state. After the task is complete, the cluster AZ display returns to normal.

Calling Method

For details, see Calling APIs.

URI

POST /v1.0/{project_id}/clusters/{cluster_id}/inst-type/{inst_type}/azmigrate

**Table 1** Path Parameters
Parameter	Mandatory	Type	Description
project_id	Yes	String	Definition Project ID. For details about how to obtain the project ID and name, see Obtaining the Project ID and Name. Constraints N/A Range Project ID of an account. The value contains 32 characters, consisting of lowercase letters and digits. Default Value N/A
cluster_id	Yes	String	Definition ID of the cluster whose AZs are to be changed. For details about how to obtain the cluster ID, see Obtaining the Cluster ID. Constraints N/A Range The value is a UUID containing 36 characters. Default Value N/A
inst_type	Yes	String	Definition Types of nodes whose AZs are to be changed. Constraints The value must be a valid node type. Before changing the AZ, you need to back up all key data to avoid data loss. Range all: all node types ess: data node ess-cold: cold data node ess-client: client node ess-master: master node Default Value N/A

Request Parameters

**Table 2** Request body parameters
Parameter	Mandatory	Type	Description
source_az	Yes	String	Definition Current AZ of the node, obtained from Querying Cluster Details. Constraints N/A Range N/A Default Value N/A
target_az	Yes	String	Definition Target AZ of the node, obtained from Regions and Endpoints in "Before You Start". Constraints N/A Range N/A Default Value N/A
migrate_type	Yes	String	Definition: AZ migration method. Constraints: To complete this AZ change, the system will try to move as few nodes as possible to rebuild the cluster. During this process, the YML configuration file of the nodes that are not modified is also updated. You need to restart the cluster to make the change take effect. If you migrate from one AZ to another, there is no need to restart the cluster. If multiple AZs are migrated, you must restart the cluster to make the change take effect. Value range: multi_az_change: Add one or two AZs for a single-AZ cluster, or add one AZ for a dual-AZ cluster. az_migrate: Migrate data from one AZ to another. Default value: N/A
agency	Yes	String	Definition Agency name. After a node is rebuilt, NICs need to be reattached to the new node. This requires you to have VPC permissions. Select an IAM agency to grant the current account the permission to access and use VPC. Constraints The agency name can contain at most 64 characters. Only letters, digits, underscores (_), and hyphens (-) are allowed. Range N/A Default Value N/A
indices_backup_check	No	Boolean	Definition: Whether to check full index snapshots. You are advised to select Check full index snapshot. This ensures that all data has been backed up, so that in case the task fails, the data can be restored using this snapshot. Constraints: N/A Value range: true: Check for full index snapshots. false: Do not check for full index snapshots. Default value: true

Response Parameters

Status code: 200

Request succeeded.

None

Example Requests

Change AZs for the current cluster.

POST https://{Endpoint}/v1.0/{project_id}/clusters/ea244205-d641-45d9-9dcb-ab2236bcd07e/inst-type/all/azmigrate

{
  "source_az" : "cn-north-4c",
  "target_az" : "cn-north-4a",
  "migrate_type" : "az_migrate",
  "agency" : "css-test-agency"
}

Example Responses

None

Status Codes

Status Code	Description
200	Request succeeded.
400	Invalid request. The client should not repeat the request without modifications.
403	The request is rejected. The server has received the request and understood it, but the server is refusing to respond to it. The client should not repeat the request without modifications.

Status Code

Description

200

Request succeeded.

400

Invalid request.

The client should not repeat the request without modifications.

403

The request is rejected. The server has received the request and understood it, but the server is refusing to respond to it. The client should not repeat the request without modifications.

Error Codes

See Error Codes.

Parent topic: Modify Configuration