Alibaba Cloud optimizes the kernel of ApsaraDB for Redis in a continuous way to fix security vulnerabilities and improve service stability. You can upgrade the kernel version or the minor version of an ApsaraDB for Redis instance with a few clicks in the console.

Procedure

The upgrade procedure varies based on the architecture. For more information, see the following table.

Architecture Procedure
Cluster instances
  1. Apply for resources that are required for creating an instance of a new version, such as proxy node resources.
  2. Synchronize the full and incremental data from the original instance to an instance of the new version.
  3. Switch instances. When data synchronization is close to completion, the original instance is set to the read-only state within 60 seconds until all data is synchronized. After data synchronization is completed, the system disassociates the virtual IP address (VIP) from the original instance and associates the VIP with the new instance.
    Note If you select Update During Maintenance, the system performs the switchover operation within the maintenance window of the instance.
  4. Complete the upgrade. Release the resources of the original instance and change the the new instance to the Running state.
Read/write splitting instances
Standard instances
  1. Upgrade the replica node. Stop the original replica node and then start a replica node of a later version.
  2. Synchronize data from the master node to a replica node of a later version.
  3. Switch from the master node to the replica node. When data synchronization is close to completion, the instance is set to the read-only state within 60 seconds until all data is synchronized. After data synchronization is completed, the system disassociates the VIP from the master node and associates the VIP to the replica node. Meanwhile, the system switches the master and replica nodes to promote the replica node of a later version to the master node.
    Note If you select Update During Maintenance, the system switches the master and replica nodes within the maintenance window of the instance.
  4. Upgrade the master node that is demoted to replica node. The original master node becomes a replica node. The system repeats Step 1 and Step 2 to upgrade the replica node and synchronize data.
  5. Complete the upgrade. The instance is changed to the Running state.

Impacts

  • The Redis service remains unaffected during the phases of applying for resources, upgrading replica nodes, and synchronizing data.
  • During the instance switchover or master/replica switchover, the instance experiences transient connections for a few seconds. The instance stays in the read-only state within 60 seconds until all data is synchronized. Upgrade the instance during off-peak hours and make sure that your application is configured with a reconnection mechanism.
  • When you upgrade the major version of an instance of ApsaraDB for Redis 4.0, Bloom filter-related API operations, such as BF.ADD, are no longer supported.
    Notice Bloom filter-related API operations on existing instances of ApsaraDB for Redis 4.0 are only for internal use. In addition, newly purchased instances of ApsaraDB for Redis 4.0 and major versions later than 4.0 no longer support Bloom filter-related API operations. Therefore, if you call Bloom filter-related API operations, you will fail to perform cache analytics and unknown errors may occur. We recommend that you change the instance to ApsaraDB for Redis Enhanced Edition (Tair) (Performance-enhanced instances) that supports the optimized Bloom filter.

Procedure

  1. Log on to the ApsaraDB for Redis console.
  2. In the top navigation bar of the page, select the region where the instance is deployed.
  3. On the Instances page, click the ID of the instance.
  4. In the Basic Information section, click Minor Version Upgrade.
    Figure 1. Upgrade the minor version
    Upgrade the minor version
    Notice The system automatically detects the minor version of an instance. If you cannot click Minor Version Upgrade, it indicates that the instance is upgraded to the latest minor version.
  5. In the panel that appears, select the time when you want to perform the upgrade.
    Note The instance experiences transient connections for a few seconds and stays in the read-only state for 60 seconds or less during instance switchover or master/replica switchover. We recommend that you select Update During Maintenance. This way, the system performs the switchover operation within the maintenance window of the instance to minimize the impact. For more information about how to modify the maintenance window, see Specify a maintenance window.
  6. In the message that appears, click OK.

FAQ

Q: Why does an instance changes to the Upgrading Minor Version state after I select Update During Maintenance to upgrade the minor version?

A: When the system prepares for upgrades, such as applying for resources and synchronizing data, instances or master and replica nodes cannot be switched over. This way, instances that provide services are not affected.
Note The instance experiences transient connections for a few seconds and stays in the read-only state for 60 seconds or less only when the system switches the instances or master and replica nodes.

Related operations

API Description
ModifyInstanceMinorVersion Upgrades the minor version of an ApsaraDB for Redis instance.