# AWS Notes
## Lambdas (FaaS)
* If operating within a VPC, cold start time is pretty long (10+ seconds)
* Lambdas can operate for a maximum of 15 minutes
* If a Lambda needs to hit a resource behind a VPC, it will require 1 ENI (Elastic Network Interface)
* Maximum concurrent lambdas is 1000
* After Lambdas are initiated, they can be _warm_. This means there is no cold start time
* You can test Lambdas locally using the `sam` cli tool. Local lambdas are invoked within a Docker container.
* If Lambdas error out, they will retry for a certain number of times.