resource/aws_elasticache_cluster: Cannot specify Redis 6.x

[gdavison]

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Description

AWS documentation for ElastiCache for Redis states that

Beginning with Redis 6, ElastiCache for Redis will offer a single version for each Redis OSS major release, rather than offering multiple minor versions. Versionless engine support is designed to minimize confusion and ambiguity on having to choose from multiple minor versions. ElastiCache for Redis will also automatically keep your cache cluster up to date on the selected major version (Redis 6 and above). By providing the updated engine version, it ensures improved performance and enhanced security.

You specify the engine version by using 6.x. ElastiCache for Redis will automatically invoke the preferred minor version of Redis 6 that is available.

When creating an aws_elasticache_cluster, engine_version can be set to 6.x, but any subsequent terraform plan or terraform apply will show a difference. If the terraform apply is continued, it fails with the error

Error: error updating ElastiCache cluster (<id>): InvalidParameterCombination: Upgrading minor engine version for redis '6.x' using modify API is not allowed, please use Service Updates

Affected Resource

• aws_elasticache_cluster

References

• The equivalent issue for aws_elasticache_replication_group: Elasticache redis 6.x support #15625

[ghost]

This has been released in version 3.38.0 of the Terraform AWS provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template for triage. Thanks!

[github-actions]

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