Alibaba Cloud continuously optimizes the kernel of ApsaraDB for Redis to provide more features 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 ApsaraDB for Redis console.

Workflow

Object Architecture Workflow
Instance minor version

Cluster

Read/write splitting

  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 is synchronized to completion, the original instance is put into the read-only state and remains in the state for up to 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 specified maintenance window.
  4. Check that the upgrade is complete. Then, release the original instance and change the state of the new instance to Running.
Standard
  1. Upgrade the original replica node. In this step, you must 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 is synchronized to completion, the original instance is put into the read-only state and remains in the state for up to 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 specified maintenance window.
  4. Upgrade the new replica node (original master 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

Read/write splitting

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

Impacts

Object Impact
Instance 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 for a few seconds. The original instance stays in the read-only state for up to 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 original instance into a performance-enhanced instance of the ApsaraDB for Redis Enhanced Edition (Tair) to support the optimized Bloom filters. For more information about performance-enhanced instances, see Performance-enhanced instances.
Proxy minor version
  • Proxy nodes support hot upgrades. Proxy nodes of the new version can restore a connection based on the client connection information of proxy nodes of the earlier version. This ensures that upgrades do not interrupt services. However, a millisecond-level latency jitter may occur during the upgrades.
  • The hot upgrades are valid only for normal connections. The execution of the block, transaction, Pub, and Sub commands is interrupted during hot upgrades. Make sure that these commands support the reconnection mechanism.
  • If a 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 endpoints and private endpoints, see Proxy mode and Direct connection mode.

Precautions

Grayscale releases of later instance minor versions may be implemented only in specific regions. The system checks the minor version of your instance. If your instance is of the latest minor version, the Minor Version Upgrade or Upgrade Proxy button in the ApsaraDB for Redis console cannot be found or clicked.

Procedure

  1. Log on to the ApsaraDB for Redis console and go to the Instances page. In the top navigation bar, select the region in which the instance is deployed. Then, find the instance and click the instance ID.
  2. In the Basic information section, move the pointer over the icon on the right of Minor Version Upgrade or 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 critical update.

    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. LOW-level updates are also included in MEDIUM-level updates.
    HIGH Red Critical update. This level includes major updates that ensure stability or security, such as fixing a vulnerability or defect. LOW-level and MEDIUM-level updates are also included in HIGH-level updates.
  3. After you view the release notes of minor versions, click Minor Version Upgrade or Upgrade Proxy.
  4. In the panel that appears, select the time when you want to perform the update.
    Note The instance experiences transient connections for a few seconds and stays in the read-only state for up to 60 seconds during instance switchovers or master/replica switchovers. We recommend that you click Update During Maintenance to configure switchovers to be performed during the maintenance window of the instance. This way, the impacts of switchovers are minimized for the instance. For more information about how to modify the maintenance window, see Set a maintenance window.
  5. 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 are not switched over. This way, instances that provide services are not affected.

Note The instance experiences transient connections for a few seconds and then remains in the read-only state for up to 60 seconds only during instance switchovers or master/replica switchovers.

Related API operations

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.