Promotion of Replicas
Last updated:2026-02-04 15:29:51
Scenarios
Replica promotion refers to the process of manually promoting a fully synchronized replica node to the new master node when a potential risk is detected or an alarm is triggered for the master node. This operation enables a hot switchover before an actual master node failure occurs, ensuring zero interruption for data services. It is a core Ops capability for preventive maintenance.
Version Description
The principle of promoting a replica node to the master node (group) is to execute the cluster failover command in the cluster, switching the role of the current master node to a replica node. The specific supported versions are as follows:
Storage Engine | Supported Version | Supported Architecture |
Redis Edition | 4.0 or later | Standard architecture and cluster architecture |
Valkey Edition | 8.0 | Standard architecture and cluster architecture |
Memcached Edition | Not supported | |
Notes
Service will have a brief access jitter during the promotion process. The jitter time is within a few seconds to 3 minutes. During the switching process, blocking commands such as BLPOP, BRPOP, BRPOPLPUSH, SUBSCRIBE will fail once or multiple times.
During the replica promotion process, the instance will become read-only for less than one minute and a momentary disconnection will occur in your service; the execution process may fail, but retrying usually results in successful execution.
Prerequisites
The instance has been Configuring Multi-AZ Deployment.
The database is on v4.0 or above.
Instance status is Running.
Directions
1. Log in to the TencentDB for Redis® console.
2. Above the Instance List on the right, select the region.
3. In the Instance List, locate the Multi-AZ deployable instance that requires replica promotion.
4. Click the Instance ID to enter the Instance Details page.
5. On the Instance Details page, click the Node Management tab, click on the Promote Replica to Master at the top right of the page.
6. In the Promote to Master Node/AZ window, configure the new primary node and set the switch time, as shown in the figure below.
Standard Architecture
Cluster architecture
Interface Parameter | Parameter Meaning | Configuration Method |
Instance ID | Current multi-availability zone instance ID awaiting replica promotion. | Confirm the correctness of the instance. |
Memory Configuration | Current instance memory configuration specification. | Confirm the specification information of the instance. |
Original Master Node ID | The standard architecture displays the current primary node's ID. | Confirm the current primary node's ID information. |
New Master Node ID | The standard architecture shows this parameter, and the configuration needs to be switched to the replica node of the primary node. | Please select the replica node to be promoted to primary node from the drop-down list. |
Original Master Node Group | The cluster architecture shows this parameter, displaying the current name of the primary node set. | Confirm the current primary node set name. |
New Master Node Group | The cluster architecture shows this parameter, and the configuration needs to be switched to the replica node set of the primary node set. | Please select the replica node set to be promoted to primary node set from the drop-down list. |
Switch Time | Select the switch time period for promoting replica to primary. | Switch Now: The switch task will be initiated immediately. Switch in Maintenance Time: This indicates initiating a switch task in the maintenance window. For related introduction and configuration of the maintenance window, see Setting Maintenance Time. |
7. After the configuration is complete, confirm that there are no errors, and click OK.
Related APIs
API Name | Description |
This API only supports the promotion of multi-AZ instance replica groups and single-AZ replicas. |
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