More detail
There’s no server to manage and you pay per request and per millisecond. A function runs for at most 15 minutes. By default it runs outside your VPC; attach it to a VPC when it needs to reach private things like an RDS database.
Lambda
Upload a function; AWS runs it only when something calls it.
Think of it as: A taxi. You pay for the ride, not for owning the car.
What to know for Level 0
- A function runs for at most 15 minutes. Longer jobs belong on Fargate, or need splitting up.
- You pay per request and per millisecond of run time (scaled by memory size). An idle function costs nothing.
- By default a function runs outside your VPC and can reach public AWS services. Attach it to a VPC only to reach private things like RDS; then it needs a NAT gateway to reach public services.
- Each function has exactly one execution role: everything its code can do in AWS.
- Lambda sends whatever a function prints to CloudWatch Logs automatically, as long as the execution role allows writing logs.
- Lambda polls an SQS queue for you (an event source mapping). Set the queue's visibility timeout to at least six times the function's timeout, or messages get processed twice.