Alibaba Cloud continuously optimizes the kernel of ApsaraDB for Redis to provide more features or fix known issues to 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

ObjectArchitectureWorkflow
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 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, the system stops the original replica node and creates 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 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 with 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

ObjectImpact
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.

    After the upgrade is complete, the instance ID, endpoint, data, whitelist settings, accounts, and account passwords remain unchanged. Make sure that your application can automatically reconnect to your 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.
    Note Bloom filter-related API operations are for internal use only in existing instances that run Redis 4.0 and are no longer available for new instances that run Redis 4.0 or later. If you call Bloom filter-related API operations on the new instances, you cannot perform cache analytics and unknown errors may occur. We recommend that you change the original instance into an Enhanced Edition (Tair) DRAM-based instance to use the optimized Bloom filters. For more information about DRAM-based instances, see DRAM-based 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 that you want to manage resides. Then, find the instance and click its ID.
  2. In the Basic information section, move the pointer over the icon to 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.

    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 levelColorDescription
    LOWGreenRegular update. This level includes routine feature updates, such as adding a feature.
    MEDIUMYellowRecommended update. This level includes optimization of features and modules. LOW-level updates are also included in MEDIUM-level updates.
    HIGHRedCritical 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.
    Note For more information about the complete release notes of minor versions, see ApsaraDB for Redis Enhanced Edition (Tair), ApsaraDB for Redis Community Edition, and ApsaraDB for Redis proxy nodes.
  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.
    Warning The state of an instance changes to read-only within 60 seconds and transient connections within seconds occur when you update the minor version of the instance or a master-replica switchover is executed on the instance. To minimize impacts, we recommend you select Update During Maintenance. This way, the system performs the operation during the maintenance window. 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

OperationDescription
DescribeEngineVersionQueries the major version and minor version of an ApsaraDB for Redis instance and the release notes of minor versions.
ModifyInstanceMinorVersionUpdates the minor version of an ApsaraDB for Redis instance.