I stumbled upon this term reading AWS documenation, some instances are recommended for building fleets but I have no clue what that is. What is a front-end fleet?
A fleet of ec2 instances means a group of instances engaged in the same activity within a group such as autoscaling, load balancing, batch processing, clustering and etc.
A fron-tend fleet generally referred to a set of EC2 instancers first act upon a load. For example set of web server instancers directly getting web traffic behind a load balancer.