ElastiCache Rightsize Clusters

Opportunity Name:
ElastiCacheRightsizeCluster

AWS Resource Type:
Amazon ElastiCache (Redis and Valkey, non-clustered mode)

Opportunity Description

This CloudFix Finder and Fixer targets Amazon ElastiCache clusters using the Redis or Valkey engine in non-clustered mode. It identifies opportunities to optimize costs by resizing the instance type (node type) of the cluster to a more appropriate size based on workload demands.

The fixer ensures data integrity by automatically taking a backup of the cluster before initiating the resizing operation. This approach guarantees rollback capability and safe modification without risking data loss or service interruption.

Criteria for Identifying the Opportunity

The opportunity is identified when the following conditions are met:

• The ElastiCache cluster engine is either Redis or Valkey (case-insensitive).

• The cluster is non-clustered (ClusterEnabled = false).

• The cluster is in an available state.

• There are no pending modifications (PendingModifiedValues is empty).

• A recommended node type differs from the currently used type.

Potential Savings (if known)

Savings vary based on the current and target node types. By right-sizing clusters to better align with actual usage, significant cost reductions are achievable.

What Happens When the Fixer Is Executed?

1. Backup First:
   The fixer initiates a snapshot of the ElastiCache cluster to preserve its current state.

2. Validation of Snapshot:
   It waits until the backup is successfully completed and marked as "available".

3. Resize Operation:
   The fixer then modifies the node type of the replication group using AWS’s ModifyReplicationGroup API.

4. Monitoring and Completion:
   The cluster status is continuously monitored to ensure successful resizing. All steps are tracked for transparency.

Is It Possible to Roll Back Once CloudFix Implements the Fixer?

Yes. Because the fixer creates a backup before resizing, rollback can be performed manually by restoring the snapshot if needed.

Can CloudFix Implement the Fix Automatically Once I Accept the Recommendation?

Yes. This fixer is fully automated. Once you approve the recommendation, CloudFix will manage backup, resizing, and validation steps for you.

Does This Fix Require Downtime?

Minimal or no downtime is expected. However, resizing operations may temporarily impact performance depending on your application’s sensitivity to changes in node availability during modification.

Additional Resources

• What is Amazon ElastiCache? (AWS)

• Amazon ElastiCache API Reference