Lambda Reserved Concurrency

• Define the maximum number of concurrent instances for a AWS Lambda function (maximum function concurrency is 1000. If you need more than that, can submit a ticket)
  • We can set throttle condition, for example:
    • if synchronous invocation, return throttle error (429)
    • if aynchronous, retry and go to DLQ
  • Why?
    • Because all the lambda functions shared 1000 invocations. if 1 lambda scaled up to 1000 invocations, other lambda function will be throttled.