EC2 restart doesn't result in user-visible errors
EC2 is part of the AWS Elastic Compute Cloud, which acquires and releases resources depending on the traffic demand. Check whether your application is elastic as well by rebooting an EC2 instance.
AWS Zone Outage doesn't result in user-visible errors
AWS achieves high availability via redundancy across different Availability Zones. Ensure that failover works seamlessly by simulating Zone outages.
Verify system unavailability status during Redis latency
Verify that an increased latency in a Redis cache is handled by your application properly by having increased processing time but still being able to maintain the throughput.
Verify system unavailability status during Redis downtime
Check that your application handles a Redis cache downtime gracefully and continues to deliver its intended functionality. The cache downtime may be an unavailable Redis instance or a complete cluster.