Server-Based Services

Most of the server based services have similar concepts for handling a hardware failover automatically. This functionality is the same that handles a single availability zone failure. By creating active/standby pairs of servers that replicate and by having each member of the pair in a different availability zone, you create the infrastructure that handles both of these failure modes.

ElastiCache

ElastiCache is one of these services. You will create an ElastiCache cluster that does not have a single point of failure, and that can handle an AZ outage.

First, create an ElastiCache subnet group in the default VPC using each available subnet and then create a multi-AZ redis cluster.