Serverless

Question 1

AWS Lambda

Answer 1

Virtual function (no servers to manage)

• limited to short executions
• run on demand
• automated scaling

Question 2

Lambda@Edge

Answer 2

Lambda functions deployed alongside CloudFront CDN

Question 3

DynamoDB

Answer 3

Serverless NoSQL database with replication across 3 AZ

- made of tables with a primary key

Question 4

DynamoDB – Provisioned Throughput

Answer 4

Read Capacity Units (RCU): throughput for reads ($0.00013 per RCU)
• 1 RCU = 1 strongly consistent read of 4 KB per second
• 1 RCU = 2 eventually consistent read of 4 KB per second

Write Capacity Units (WCU): throughput for writes ($0.00065 per WCU)
• 1 WCU=1 write of 1KB per second

Question 5

DAX

Answer 5

DynamoDB Accelerator (DAX) is seamless cache for DynamoDB

Question 6

DynamoDB Streams

Answer 6

Intercept changes in DynamoDB (Create, Update, Delete)

The stream be read by AWS Lamnbda

Question 7

DynamoDB Transactions

Answer 7

All or nothing type of operations (Insert, Update & Delete)

Question 8

DynamoDB On Demand

Answer 8

Scalable capacity planning (WCU / RCU)

- 2.5x more expensive

Question 9

DynamoDB Global Tables

Answer 9

Automatic replication of DynamoDB cross region

Question 10

DynamoDB Capacity planning

Answer 10

Planned capacity for WCU & RCU

Question 11

API Gateway

Answer 11

Enables public RESTful endpoints to clients

Question 12

API Gateway - Endpoint Types

Answer 12

• Edge-Optimized (default): For global clients
• Regional: One region
• Private: within a VPC

Question 13

API Gateway - IAM Permissions

Answer 13

Allow permission of an endpoint their IAM permissions

- Leverages “Sig v4” capability where IAM credential are in headers

Question 14

API Gateway - Lambda Authorizer

Answer 14

Uses AWS Lambda to validate the 3rd party auth tokens (OAuth/SAML) in header being passed

Question 15

API Gateway - Cognito User Pools

Answer 15

Manages your own user pool (can be backed by Facebook, Google login etc…) and only helps with authentication not authorisation

Question 16

AWS Cognito

Answer 16

Gives our users an identity so that they can interact with our application

Question 17

AWS Cognito User Pools (CUP)

Answer 17

Serverless database of users for you mobile app

• Can enable Federated Identities (FB, Google)
• uses JWT

Question 18

AWS Cognito – Federated Identity Pools

Answer 18

Similar to CUP, except the federated identity (token) is traded in for temporary credentials that can have IAM policies attached to them

Question 19

AWS Cognito (App) Sync

Answer 19

Store user preferences, configuration, state of app and must be used with Cognito Federated Identity Pool

Question 20

AWS SAM

Answer 20

Serverless Application Model is a framework for developing and deploying serverless applications
- configuration is in YAML code