New – Redis 6 Compatibility for Amazon ElastiCache

After the last Redis 5.0 compatibility for Amazon ElastiCache, there has been lots of improvements to Amazon ElastiCache for Redis including upstream supports such as 5.0.6.

Earlier this year, we announced Global Datastore for Redis that lets you replicate a cluster in one region to clusters in up to two other regions. Recently we improved your ability to monitor your Redis fleet by enabling 18 additional engine and node-level CloudWatch metrics. Also, we added support for resource-level permission policies, allowing you to assign AWS Identity and Access Management (IAM) principal permissions to specific ElastiCache resource or resources.

Today, I am happy to announce Redis 6 compatibility to Amazon ElastiCache for Redis. This release brings several new and important features to Amazon ElastiCache for Redis:

• Managed Role-Based Access Control – Amazon ElastiCache for Redis 6 now provides you with the ability to create and manage users and user groups that can be used to set up Role-Based Access Control (RBAC) for Redis commands. You can now simplify your architecture while maintaining security boundaries by having several applications use the same Redis cluster without being able to access each other’s data. You can also take advantage of granular access control and authorization to create administration and read-only user groups. Amazon ElastiCache enhances the new Access Control Lists (ACL) introduced in open source Redis 6 to provide a managed RBAC experience, making it easy to set up access control across several Amazon ElastiCache for Redis clusters.
• Client-Side Caching – Amazon ElastiCache for Redis 6 comes with server-side enhancements to deliver efficient client-side caching to further improve your application performance. Redis clusters now support client-side caching by tracking client requests and sending invalidation messages for data stored on the client. In addition, you can also take advantage of a broadcast mode that allows clients to subscribe to a set of notifications from Redis clusters.
• Significant Operational Improvements – This release also includes several enhancements that improve application availability and reliability. Specifically, Amazon ElastiCache has improved replication under low memory conditions, especially for workloads with medium/large sized keys, by reducing latency and the time it takes to perform snapshots. Open source Redis enhancements include improvements to expiry algorithm for faster eviction of expired keys and various bug fixes.

Note that open source Redis 6 also announced support for encryption-in-transit, a capability that is already available in Amazon ElastiCache for Redis 4.0.10 onwards. This release of Amazon ElastiCache for Redis 6 does not impact Amazon ElastiCache for Redis’ existing support for encryption-in-transit.

In order to apply RBAC to a new or existing Redis 6 cluster, we first need to ensure you have a user and user group created. We’ll review the process to do this below.

Using Role-Based Access Control – How it works
An alternative to Authenticating Users with the Redis AUTH Command, Amazon ElastiCache for Redis 6 offers Role-Based Access Control (RBAC). With RBAC, you create users and assign them specific permissions via an Access String.

If you want to create, modify, and delete users and user groups, you will need to select to the User Management and User Group Management sections in the ElastiCache console.

ElastiCache will automatically configure a default user with user ID and user name “default”, and then you can add it or new created users to new groups in User Group Management.

If you want to change the default user with your own password and access setting, you need to create a new user with the username set to “default” and can then swap it with the original default user. We recommend using your own strong password for a default user.

The following example shows how to swap the original default user with another default that has a modified access string via AWS CLI.

$ aws elasticache create-user \
 --user-id "new-default-user" \
 --user-name "default" \
 --engine "REDIS" \
 --passwords "a-str0ng-pa))word" \ 
 --access-string "off +get ~keys*"

Create a user group and add the user you created previously.

$ aws elasticache create-user-group \
  --user-group-id "new-default-group" \
  --engine "REDIS" \
  --user-ids "default"

Swap the new default user with the original default user.

$ aws elasticache modify-user-group \
    --user-group-id "new-default-group" \
    --user-ids-to-add "new-default-user" \
    --user-ids-to-remove "default"

Also, you can modify a user’s password or change its access permissions using modify-user command, or remove a specific user using delete-user command. It will be removed from any user groups to which it belongs.

Similarly you can modify a user group by adding new users and/or removing current users using modify-user-group command, or delete a user group using delete-user-group command. Note that the user group itself, not the users belonging to the group, will be deleted.

Once you have created a user group and added users, you can assign the user group to a replication group, or migrate between Redis AUTH and RBAC. For more information, see the documentation in detail.

Redis 6 cluster for ElastiCache – Getting Started
As usual, you can use the ElastiCache Console, CLI, APIs, or a CloudFormation template to create to new Redis 6 cluster. I’ll use the Console, choose Redis from the navigation pane and click Create with the following settings:

Select “Encryption in-transit” checkbox to ensure you can see the “Access Control” options. You can select an option of Access Control either User Group Access Control List by RBAC features or Redis AUTH default user. If you select RBAC, you can choose one of the available user groups.

My cluster is up and running within minutes. You can also use the in-place upgrade feature on existing cluster. By selecting the cluster, click Action and Modify. You can change the Engine Version from 5.0.6-compatible engine to 6.x.

Now Available
Amazon ElastiCache for Redis 6 is now available in all AWS regions. For a list of ElastiCache for Redis supported versions, refer to the documentation. Please send us feedback either in the AWS forum for Amazon ElastiCache or through AWS support, or your account team.

– Channy;