Designing AWS Environments

Auto scaling

Auto scaling allows us to horizontally scale, by launching and terminating instances in response to the request to load. So if our application gets a lot of traffic during the day, perhaps we will have ten instances getting requests from the ELB. But overnight, we don't have a lot of users, so maybe we'll go down to a minimum of two. We can specify the minimum and maximum number of instances for our auto scaling group. To maintain our high availability, we should probably never specify a minimum of less than two. When you create an auto scaling group, you will also have to define the launch configuration. This is simply all of the attributes of the EC2s that the auto scaling group will launch, including the AMI, instance size ...