AWS is closed source in some areas because they have not released the software they use to manage their platform. In other areas they have released the source code. It’s actually a pain in the ass that tools like LocalStack have evolved to fix.
Their license, the SSPL, is actually pretty fucking far from open. That being said for anyone not a platform provider it’s basically open source so you can consider it as such. You just have to deal with SSPL callouts when you do compliance reviews.
Edit: the meme says “closed source” which is patently false for Mongo
That’s why I started by saying it’s pretty far from open. I refuse to touch SSPL projects at work because they’re not open. You have rights until you want to sell something the licensor might misconstrue as theirs. Terraform’s BSL is a new iteration of this bullshit.