Lamdba (Compute)

Question 1

What does Lambda do?

Answer 1

You upload some code and it runs it for you

Question 2

When do you pay for Lambda?

Answer 2

You only pay for Lambda when code runs

Question 3

What is key difference between Elastic Beanstalk and Lambda

Answer 3

Elastic Beanstalk is going to create and manage infrastructure for you and is going to use EC2 instances. Meant to do a full task or job.

Lambda you have no access to underlying hardware so it’s known as serverless. Does a single function well

Question 4

Cloud Formation vs Elastic Beanstalk

Answer 4

Cloud Formation you still need to do deployments you would need to set up to deploy it. Cloud Formation is like blue print.

You can deploy it in Elastic Beanstalk. It uses Cloud Formation under the hood

Question 5

What can Lambda help with?

Answer 5

Building an event driven architecture

Question 6

Do the Autoscaling Group and Load Balancer work together

Answer 6

Yes

Question 7

What is the serverless application model (SAM)

Answer 7

SAM is a way that you can define your infrastructure that is serverless ie., lambda and code

So it updates maintains etc

Question 8

Java code and it’s dependencies are deployed in a lambda function, but it fails because the package size is too big

What should you do that wouldn’t need major QA testing

Answer 8

Create a Lambda layer for the dependencies

Question 9

Popular serverless app that predicts stock prices has runtime of 100s and 60 requests per second

Its performance decrease during trading times

What solution could overcome performance issue

Answer 9

Initiate a Service Limit Increase Request

Question 10

How can a start up switch between new versions of lambda function and rollback easily?

Answer 10

• Create alias with current version
• Point app to the alias created for Lambda function
• When you want to refresh app with next version, update alias

Question 11

What causes a Lambda job to land in a DLQ?

Answer 11

1. Function times out when processing
2. The function fails to retrieve inputs from the event

Question 12

A developer is using all at once deployment policy which causes all services to be out temporarily

What could they use instead

Answer 12

Rolling with an additional batch

Question 13

If you are using Lambda for mobile app deployment. How would you do different font themes based on if its android or ios?

Answer 13

Use the “context” object in mobile SDK because it gives the lambda function automatic access to device and app info

Question 14

How would you update SAM template used to deploy a lambda function to instantly switch traffic once it has been built and tested?

Answer 14

AutoPublishAlias: live

https://docs.aws.amazon.com/codedeploy/latest/userguide/tutorial-lambda-sam-template.html

Question 15

If your output lambda is in a different format by mistake what error code will you get?

Answer 15

502

Question 16

If you have many lambda functions that read from Kinesis Streams which is slowing down your app. How do you increase read throughput and reduce latency in your app?

Answer 16

Create a data stream consumer