[SAA + SAP] 07. Lambda

SAA

• CPU is linked to RAM (cannot be set manually)
• 2 vCPU are allocated after 1.5G of RAM are used... if you are enabling multi thread, you cannot leverage 2 vCPU

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SAP

• If you application need to response under 100ms, serverless articture is not good for you
• All the serverless techs you use, they will introduce some latencies and sums up

Security

• Lambda deploy in AWS outside VPC cannot talk to the RDS deployed in a VPC & Private subnet
• Solution is to deploy Lambda in VPC & Private subnet, then it can talk to RDS
• But will have problem to access public www
• Solution is to have a route to NAT in public subnet, and NAT has a route to IGW which can access www
• How about access DynamoDB which not in VPC
• Solution is to use VPC endpoint to access it

Synchronous Invocations

• CLI & SDK, wait for response
• Exponential backoff for retry

Asynchronous Invocation

• DLQ: for failed processing

• Should be async invocation, so APi Gateway is NOT correct.
• SQS no need for Lambda to setup DLQ

Event Source Mappinp

• For stream
• Lambda poll the stream
• If error, will do retry until success
• idempotent

Destinations

• CodeDeploy can help to shift traffic for Lambda function