Chp 9: AWS Fundamentals- RDS, Aurora, & Elasticache

Question 1

What is Amazon Aurora

Answer 1

Amazon Aurora is a MySQL and PostgreSQL-compatible relational database built for the cloud that combines the performance and availability of traditional enterprise databases with the simplicity and cost-effectiveness of open source databases.

Question 2

Advantages of Amazon Aurora

Answer 2

• An AWS managed service
• automated updates
• automated backups

Question 3

RDS- Autoscaling group

Answer 3

Helps increase storage on your RDS DB instance dynamically. It scales automatically when it detects resources are running out.

Question 4

When is using RDS (ASG) useful?

Answer 4

useful for apps with an unpredictable workload

Question 5

Who sets the RDS max storage threshold

Answer 5

user have to manually set it

Question 6

How many read replicas for RDS?

Answer 6

5 read replicas

Question 7

Can read replicas scale within regions? wherelse?

Answer 7

regions, across AZ, and across region

Question 8

T/F RDS read replicas cannot be promoted to its own database

Answer 8

FALSE… It CAN be promoted

Question 9

How do apps leverage read replicas?

Answer 9

They have to update the connection string

Question 10

RDS read replicas are used for what kind of statements?

Answer 10

READ statements

Question 11

RDS Read replicas – is there a cost when data goes from one AZ to another?

Answer 11

yes there is

Question 12

When are RDS read replicas free?

Answer 12

when they are within the same region

Question 13

How to set up RDS read replicas for disaster recovery?

Answer 13

Read replicas are set up as multi AZ

Question 14

is RDS multi AZ used for scaling and availability?

Answer 14

its used to increase availability and not used for scaling

Question 15

Ecryption tupes for RDS read replicas

Answer 15

1. at rest encryption

2. in flight encryption

Question 16

Describe at rest encryption

Answer 16

• encrypt using aes-256
• encryption has to be defined at launch time
• if the master is not encrypted, then the read replicas cannot be encrypted

Question 17

Describe in flight encryption

Answer 17

• SSL certs

Question 18

T/F: A user can copy a snapshot of an unencrypted db can turn into a encrypted one

Answer 18

tru

Question 19

what subnet is used when deploying a RDS database?

Answer 19

RDS db are usually deployed within a private subnet

Question 20

describe RDS security

Answer 20

security works by leveraging security groups. it controls which ip/sg can communicate with RDS

Question 21

describe access management for RDS

Answer 21

• IAM policies control who can manage RDS
• traditional UN & PW can be used to login into db
• IAM-based authentication can be used to login into RDS MySQL + Postgres

Question 22

are mysql and postgres supported as Aurora DB>

Answer 22

yes

Question 23

Aurora High Availability + Read Scaling

Answer 23

• 6 copies of your data across 3 AZ
• 1 is a master /writes
• support for cross region replication

Question 24

When is aurora cross region read replicas useful?

Answer 24

useful for disaster recovery

Question 25

describe aurora global db

Answer 25

- 1 primary region with r/w - 5 secondary read only - up to 16 read replicas per secondary region - helps for decreasing latency

Question 26

What is ElastiCache?

Answer 26

Amazon ElastiCache is a fully managed, in-memory caching service supporting flexible, real-time use cases. You can use ElastiCache for caching, which accelerates application and database performance, or as a primary data store for use cases that don't require durability like session stores, gaming leaderboards, streaming, and analytics. ElastiCache is compatible with Redis and Memcached.

Question 27

Describe ElastiCache Redis

Answer 27

- multi AZ with auto-failover - read replicas to scale reads and have high availability - data durability using persistence - backup + restore features

Question 28

Describe ElastiCache Memcahced

Answer 28

- multinode for partitioning of data - no high availability (replication) - non persistent - no backup & restore - multithreaded architecture

Question 29

describe cache in elasticache

Answer 29

- - do not support IAM authentication | - - IAM policies on elasticache are only used for AWS API-lvl security

Question 30

describe redis cache security

Answer 30

- you can set pw/token when creating a redis cluster - an extra lvl of security for your cache - support SSL in flight encryption

Question 31

describe memcached cache security

Answer 31

- supports SASL based authentication

Question 32

use case for elasticache

Answer 32

gaming leaderboard

Question 33

Patterns for ElastiCache

Answer 33

1. lazy-loading: all the read data is cached, data can become stale in cache 2. write through: adds or update data in the cache when written to a DB 3. session store: store temp session data in a cache