Alibaba Cloud continuously optimizes the kernel of ApsaraDB for Redis to provide more feature or fix known issues and enhance service stability. You can update the kernel version (minor version) of an ApsaraDB for Redis instance with a few clicks in the console.

Workflow

Object Architecture Workflow
Minor version

Cluster master-replica instances

Read/write splitting instances
  1. Apply for resources that are required to create an instance of a new major version. These resources include proxy node resources.
  2. Synchronize the full data and incremental data from the original instance to the new instance.
  3. Switch your workloads over from the original instance to the new instance. 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 complete, ApsaraDB for Redis disassociates the virtual IP addresses (VIPs) from the original instance and associates the VIPs with the new instance.
    Note If you select Update During Maintenance, ApsaraDB for Redis performs the switchover within the maintenance window that you specify.
  4. Check that the upgrade is complete. Then, release the original instance and change the status of the new instance to Running.
Standard master-replica instances
  1. Upgrade the original replica node. In this step, you need to stop the original replica node and create a replica node of a new major version.
  2. Synchronize data from the original master node to the new replica node.
  3. Switch your workloads over from the original master node to the new 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 complete, ApsaraDB for Redis disassociates the VIPs from the original master node and associates the VIPs to the new replica node. In addition, ApsaraDB for Redis switches your workloads over from the original master node to the new replica node and promotes the new replica node to the new master node. The original master node is demoted to the new replica node.
    Note If you select Update During Maintenance, ApsaraDB for Redis performs the switchover within the maintenance window that you specify.
  4. Upgrade the original master node, namely, the new replica node. ApsaraDB for Redis repeats Step 1 and Step 2 to perform the upgrade and synchronize data.
  5. Check that the upgrade is complete. If the instance is in the Running state, the upgrade is successful.
Proxy minor version

Cluster master-replica instances

Read/write splitting instances

 Proxy servers support hot updates. A proxy server of the new version can restore the connection based on the client connection information of the proxy server of the earlier version. This ensures uninterrupted connections. However, a millisecond-level latency jitter may occur during the update.

Impact

Object Impact
Minor version
  • When you apply for resources, upgrade the replica node, or synchronize data, your ApsaraDB for Redis service remains available.
  • When you switch your workloads over from the original instance to a new instance or from the master node to the replica node in the original instance, you may experience transient connections that last a few seconds. The original instance stays in the read-only state within 60 seconds until all data is synchronized. We recommend that you upgrade the original instance during off-peak hours and make sure that your application is configured to automatically reconnect to the original instance.
  • If the original instance runs Redis 4.0, Bloom filter-related API operations, such as BF.ADD, are no longer supported after you upgrade the major version of the original instance to a version later than Redis 4.0.
    Notice Bloom filter-related API operations on existing instances of ApsaraDB for Redis 4.0 are only for internal use. In addition, new instances that run Redis 4.0 or later no longer support Bloom filter-related API operations. Therefore, if you call Bloom filter-related API operations, you cannot perform cache analytics and unknown errors may occur. We recommend that you change the edition of the original instance to ApsaraDB for Redis Enhanced Edition (Tair) to supports the optimized Bloom filter. For more information, see Performance-enhanced instances.
Proxy minor version
  • Proxy servers support hot upgrades. A proxy server of the new version can restore the connection based on the client connection information of the proxy server of the earlier version. This ensures uninterrupted connections. However, a millisecond-level latency jitter may occur during the upgrade.
  • The hot upgrade is only valid for normal connections. The execution of the block, Transaction, Pub, and Sub commands will be interrupted. Make sure that these commands support the reconnection mechanism.
  • If the Redis client uses a private endpoint to connect to the ApsaraDB for Redis instance, no commands are affected by a proxy upgrade.
Note For more information about proxy addresses and private endpoints, see Proxy mode and Direct connect mode.

Procedure

  1. Log on to the ApsaraDB for Redis console.
  2. In the top navigation bar of the page, select the region in which the instance is deployed.
  3. On the Instances page, click the ID of the instance.
  4. In the Basic Information section, you can view the minor version of the current instance.
  5. In the Basic Information section, move the pointer over Minor Version Upgrade or the right icon of Upgrade Proxy to view the minor version of the current instance, the minor version to which you can update, and the release notes of minor versions.
    Figure 1. View release notes of minor versions
    View release notes of minor versions

    The icon changes colors based on the minor version update level. The update level is displayed in green, yellow, or red to represent the regular, recommended, or important update. This help you distinguish the update level.

    Update level Color Description
    LOW Green Regular update. This level includes routine feature updates, such as adding a feature.
    MEDIUM Yellow Recommended update. This level includes optimization of features and modules, such as optimizing a feature. Moreover, LOW-level updates are included in this level.
    HIGH Red Important update. This level includes major updates that ensure stability or security, such as fixing a vulnerability or defect. Moreover, LOW-level and MEDIUM-level updates are included in this level.
    Note For the complete release notes of minor versions, see ApsaraDB for Redis Enhanced Edition, ApsaraDB for Redis Community Edition, and ApsaraDB for Redis proxy servers.
  6. After you view the release notes of minor versions, click Minor Version Upgrade or Upgrade Proxy.
    Notice The system checks the minor version of your instance. If your instance is of the latest version, the Minor Version Upgrade or Upgrade Proxy button cannot be found or clicked.
  7. In the panel that appears, select the time when you want to perform the update.
    Note The instance experiences disconnections 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 specify switchovers to be performed during the maintenance window of the instance by clicking Update During Maintenance. This way, the impacts of switchovers are minimized for the instance. For more information about how to modify the maintenance window, see Specify a maintenance window.
  8. And then click OK.

FAQ

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

A: When the system prepares for updates, 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 disconnections for a few seconds and then remains in the read-only state for 60 seconds or less only during instance switchover or master/replica switchover.

Related operations

API operation Description
DescribeEngineVersion Queries the major version and minor version of an ApsaraDB for Redis instance and the release notes of minor versions.
ModifyInstanceMinorVersion Updates the minor version of an ApsaraDB for Redis instance.