Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AWS Solutions Architect Associate > Chp 8: High Availability + Scalability --> ELF and ASG > Flashcards

Chp 8: High Availability + Scalability --> ELF and ASG Flashcards

1
Q

What is scalability? What are the types

A
  • apps/system can handle greater loads by adapting

- types: horizontal/vertical

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is vertical scalability?

A
  • increasing the size

- scale up/down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is horizontal scalability

A

increase the # of instances

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

high availability goes hand in hand with what?

A

horizontal scalability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what does high availability mean?

A
  • run app/system in at least 2 data centers (= AZ)

- can be active or passive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a load balancer?

A
  • servers that forward traffic to multiple servers downstream
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why use a load balancer?

A
  • spread load across multiple downstream instances
  • expose a single point of access
  • regular health checks
  • provide SSL termination
  • enforce stickiness with cookies
  • high availability
  • separate public traffic from private traffic
  • AWS takes care of everything
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are health checks?

A

is a clone on a port/route

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the types of load balancers?

A
  1. classic
  2. application
  3. network
  4. gateway
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

classic load balancer/

A

http, https, tcp, ssl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Application load balancer

A
    • http, https, websocket
    • good for microservices and container
    • port mapping
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

ALB target groups

A
  • ec2 instances
  • ec2 tasks
  • lambda function
  • ip address
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many groups can ALB be routed to?

A

many

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Health checks are at what level

A

target group level

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

ALB– hostnames or IPs

A

fixed hostname. it doesnt see IP of the client

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

ALB– how does it get the IP of the client?

A

used header x-forwarded port

17
Q

network load balancer

A
    • tcp, tls, udp
    • one static IP per AZ
    • supports assigning elastic IP
18
Q

NLB – target groups

A
  • ec2 instances
  • ip addresses (private ips)
  • ALB
19
Q

Gateway load balancer

A
  • operates at layer 3/network

- single entry/exit for all traffic

20
Q

Gateway load balancer’s target group

A
  • EC2 instances

- IP addresses (private IP)

21
Q

What is a sticky session

A

the same client is always redirected to the same load balancer

22
Q

sticky sessions work for which type of load balancer

A

ALB and GLB

23
Q

what happens with cross zone load balancing?

A

each load balancer instance distributes evenly across all registered instances in all AZ

24
Q

what happens without cross-zone load balancing?

A

requests are distributed in the instances of the nodes of the ELB

25
Q

What is SSL? Whats the newer version?

A
  • SSL encrypts connection

- TLS is the newer version

26
Q

Load balancers uses what kind of certs

A

x509

27
Q

Server Name Indication (SNI) – Purpose

A
  • SNI solves the problem of loading multiple SSL certs onto one web server
  • Only works for ALB + NLB
28
Q

What is an auto scaling group (ASG)

A
  • scale out to match AWS increased load
  • scale in to match a decreased load
  • ensure there’s a min + max # of running machines
  • automatically register new instances to a load balancer
29
Q

ASG Alarms

A

use cloudwatch alarms

30
Q

ASG – Scaling Policies

A
  1. target tracking
  2. simple/step scaling
  3. scheduled actions
31
Q

what happens during an ASG scaling cool down

A
  • after a scaling activity, you are in a cool down period

- during the cool down period, you will not launch or terminal additional instances

32
Q

ASG default termination policy

A
  • find the AZ which has the most # of instances
  • if there are multiple instances in the AZ to choose from, delete the one with the oldest launch config
  • ASG tries to balance the # of instances across AZ by default
33
Q

which is preferred? launch config or launch template?

A

launch template

AWS Solutions Architect Associate (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions