Auto scaling group
Auto-scaling is useful to easily scale the number of EC2 instances up or down at need.
After deploying the Weka cluster via CloudFormation, it is possible to create an auto-scaling group to ease the Weka cluster size management.
You can control the number of instances by either changing the desired capacity of instances from the AWS auto-scaling group console or defining your custom metrics and scaling policy in AWS. Once the desired capacity has changed, Weka will take care of safely scaling the instances.