Section 7: AWS Fundamentals: ELB + ASG

Question 1

Need to increase the size of your instance: Is that vertical or horizontal scalability?

Answer 1

Vertical

Section 7: AWS Fundamentals ELB + ASG

Question 2

Do you want to vertically scale a non distributed system (ex: a database, RDS, ElastiCache?)

Answer 2

In most instances, yes. Unless it’s a nosql database. Apparently those you can scale horizontally (add new instances as needed).

Section 7: AWS Fundamentals ELB + ASG

Question 3

True or false: A distributed system just means a system where it is easy to distribute the workload accross multiple systems.

Answer 3

True. Examples include the internet (idk, i guess the workload is distributed accross every device using the internet) and idk a database distributed accross multiple servers where the data can be replicated.

Section 7: AWS Fundamentals ELB + ASG

Question 4

True or false: a non distributed system means all parts of the system are in the same physical location.

Answer 4

True.

Section 7: AWS Fundamentals ELB + ASG

Question 5

What kind of scalability is it when you increase the number of instances/systems for your application?

Answer 5

Horizontal

Section 7: AWS Fundamentals ELB + ASG

Question 6

How many data centers/availability zones do you need to be running your app/system in for it to be considered highly available?

Answer 6

2

Section 7: AWS Fundamentals ELB + ASG

Question 7

True / False: The goal of high availability is to survive a data center loss? (I suppose it is doubtful that a whole availability zone goes down, probably the idea certainly applies there too. Though honestly, probably there are bigger problems if a whole AZ goes down.)

Answer 7

True

Section 7: AWS Fundamentals ELB + ASG

Question 8

Is this passive or active high availability: A Relational Database System (RDS) distributed accross multiple availability zones?

Answer 8

Passive. I suppose the idea is that you set it up that way in advance and it doesn’t, like, increase in size (your system doesn’t get dymacailly deployed to a new availability zone if you start reaching size or connection limits). I’m just guessing about why this is passive I could be totally wrong.

Section 7: AWS Fundamentals ELB + ASG

Question 9

Is this passive or active high availability: Horizontal Scaling

Answer 9

Active. If you start reaching throughput/connection/size limits, you get new instances deployed. (Steph says it’s active, but I am just guessing as to why.)

Section 7: AWS Fundamentals ELB + ASG

Question 10

Also prob not an exam:
True or false:
Vertical scaling is referred to as scaling up or down. Horizintal scaling is referred to as scaling in or out.

Answer 10

True

Section 7: AWS Fundamentals ELB + ASG

Question 11

Does high availability lend itself more towards horizontal or vertical scaling?

Answer 11

Horizontal. I suspect an argument could be made for vertical scaling being highly available, but it would have to be something like if you were vertically scaling all of your instances that you already had in multiple area zones, which would mean you were vertically scaling out your horizontally distributed system. So, really, except for special cases like that (which include horizontal scaling anyway), when we’re talking about high availability we’re probably talking about horizontally scaled systems that are already distributed accross multiple availability zones - adding new instances through the use of load balancers (LB) and auto scaling groups (ASG). Both LB’s and ASG’s kind of fall into both the category of horizontal scalability and high availability, though, when we’re talking about high availlablity, both the auto scaling group and the load balancers need to be applied to a system running in multiple availability zones.

Section 7: AWS Fundamentals ELB + ASG

Question 12

What do you call a server or set of servers that forwards traffic to multiple servers “downstream” (don’t be distracted by the use of “downstream” I think it’s perfectly useless in this sentence.)

Answer 12

Load balancers

Section 7: AWS Fundamentals ELB + ASG

Question 13

True or false: the Auto Scaling Group distributes traffic to multiple instances and monitors those instances for health, and if it seems like an instance is unhealthy and needs to be restarted, or is approaching limits, it sends info to your load balancer/trigger alarms picked up your load balancer and your load balancer restarts instances or deploys new instances (or takes them away, depending on whether it was an upper or lower usage limit that triggered the alarm).

Answer 13

True or false: False. It’s the Load Balancer that distributes traffic to multiple instances and monitors those instances for health, and if it seems like an instance is unhealthy and needs to be restarted, or is approaching limits, it sends info to your Auto Scaling Group/trigger alarms picked up your ASG and your ASG restarts instances or deploys new instances (or takes them away, depending on whether it was an upper or lower usage limit that triggered the alarm).

Section 7: AWS Fundamentals ELB + ASG

Question 14

When you use a load balancer, how many points of access (DNS) to your application are there?

Answer 14

1

Section 7: AWS Fundamentals ELB + ASG

Question 15

True or false, in addition to what you already know about load balancers, load balancers can:
* Provide SSL termination (enforce HTTPS for your websites)
* enforce stickiness with cookies
* separate public traffic from private traffic

Answer 15

True

Section 7: AWS Fundamentals ELB + ASG

Question 16

Is the Elastic Load Balancer a managed load balancer? (That is, does AWS take guarantee it will work/take care of upgrades/maintence etc.)

Answer 16

Yes

Section 7: AWS Fundamentals ELB + ASG

Question 17

True/false: Is the Elastic Load Balancer integrated with all of the following AWS offerings/services?
* EC2, EC2 Auto Scaling Groups, Amazon ECS
* AWS Certificate Manger (ACM), CloudWatch
* Route 53, AWS WAF, AWS Global Accelerator

Answer 17

True. Idek what AWS Global Accelerator is yet though, honestly.

Reverse question would be: what aws services does elb work with?

Section 7: AWS Fundamentals ELB + ASG

Question 18

True or false: Health Balances enable a load balancer to know if instances it forwards traffic to are healthy enough to reply to requests.

Answer 18

False. It’s Health Checks.

Section 7: AWS Fundamentals ELB + ASG

Question 19

The port a health check is set up to use is variable (example, port 4567). What is the common route/(endpoint) used to do the health checks used by load balancers?

Answer 19

/health. If the response isn’t a 200, the ELB won’t send traffic to that instances.

Section 7: AWS Fundamentals ELB + ASG

Question 21

There are four kinds of managed load balancers on AWS. We’re going to ignore one of those four (Classic Load Balancer) since it’s being deprecated. What are the other three main types of load balancers AWS offers?

Answer 21

• Application Load Balancer (2016)
• Network Load Balancer (2017)
• Gateway Load Balanacer (2020)

Section 7: AWS Fundamentals ELB + ASG

Question 21

When using a load balancer, there are two security groups involved (not like the kind of security group that a user belongs to, but the kind that services can belong to). What are those and how are they used?

Answer 21

The Load Balancer Security Group and the Application Security group.

The Load Balancer Security Group is the security group that allows (or rejects) traffic between people using your app/site and your load balancer. An example of a Load Balancer Security Group is one that is set up to allow:
[{Type: HTTP, Protocal: TCP, Port Range: 80, Source: 0.0.0.0/0, Description: allow http from anywhere}, {Type: HTTPS, Protocal: TCP, Port Range: 443, Source: 0.0.0.0/0, Description: allow https from anywhere}].

The Application Security Group is the security group that allows traffic to your application only from your load balancer, and rejects traffic traffic from everywhere else. Say your Load Balancer had a security group ID of sg-123456789. Then an example of an Application Security Group setup is: {Type: HTTP, Protocal: TCP, Port Range: 80, Source: sg-123456789, Description: allow traffic only from the Load Balancer Security Group}

Section 7: AWS Fundamentals ELB + ASG

Question 22

True or False: Network Load Balancers have the following qualities:
* Load balancing to multiple HTTPS apps across machines (target groups, examples: EC2 instances, ECS tasks, lambda functoins, private IP addresses) and to multiple apps on the same maching (ex: containers)
* support for HTTP/2 and WebSocket
* Support redirects (from HTTP to HTTPS, for example)
* Routing based on path in URL (ex: anna.com/books and anna.com/birds)
* Routing based on hostname in URL (stuff.anna.com and things.anna.com)
* Routing based on query string, headers (anna.com/books?category=educational&liked=true)
* Great fit for things like Docker and Amazon ECS
* has port mapping to redirect to a dynamic port in ECS (what?)
* Fixed hostname (XXX.region.elb.amazonaws.com)
* Application servers don’t see the IP of the client directly. True IP of client is inserted into header X-Forwarded-For. True port of client is inserted into header X-Forwarded-Port and proto (X-Forwarded-Proto).

Answer 22

False! It’s Application Load Balancers that have those qualities!

Section 7: AWS Fundamentals ELB + ASG

Question 23

Need a load balancer that has:
* extreme performance
* TCP or UDP traffic
* static IPs
which kind do you use?

Answer 23

Network Load Balancer

Section 7: AWS Fundamentals ELB + ASG

Question 24

True/False:
“Among the two most common transport protocols on the Internet, TCP is reliable and UDP isn’t. HTTP therefore relies on the TCP standard, which is connection-based. Before a client and server can exchange an HTTP request/response pair, they must establish a TCP connection, a process which requires several round-trips” Mozilla.org

Answer 24

True

Question 25

Which load balancer:
* Forwards TCP and UDP traffic to your instances
* can handle milllions of requests per second
* has 1/4 latency of another load balancer?

Answer 25

Network load balancers (layer 4, whatever that means. vague memories of a network column looking thing.)
it’s got a latency of about 100ms (vs the latency about about 400ms that the Application Load Balancer (ALB) has).

Section 7: AWS Fundamentals ELB + ASG

Question 26

Are Network Load Balancers included in the AWS free tier?

Answer 26

No

Section 7: AWS Fundamentals ELB + ASG

Question 27

What kinds of target groups can you associate with a Network Load Balancer?

Answer 27

• EC2 Instances
• Private IP Addresses
• Application Load Balancer

Section 7: AWS Fundamentals ELB + ASG

Question 28

True/False:
an Application Load Balancer (ALB) can route traffic from the Domain Name Service (basically the url) of the ALB to one of two EC2 instances (each with their own public IPv4 address). Furthermore, you can prevent others from using your EC2 instance’s public IPv4 addresses by making it so that they (the instances) only accept traffic from the applicaion load balancer (by stating that inbound traffic, instead of coming from a is only allowed from the CIDR address (IP address) value, is only allowed from the security group of the application load balancer)

Answer 28

True

Section 7: AWS Fundamentals ELB + ASG

Question 29

True/False: You can use a Network Load Balancer that has as it’s target group an application load balancer. This is because with the network load balancer you could get fixed IP addresses, and thanks to the ALB, you can get all the rules that you have around handling HTTP traffic

Answer 29

True

Section 7: AWS Fundamentals ELB + ASG

Question 30

True/False Health checks performed by network load balancer target groups support three different types of protocols: TCP, HTTP, HTTPS. So if your backend supports HTTP or HTTPS then it def possible for you to define a health check on these protocols.

Answer 30

True

Section 7: AWS Fundamentals ELB + ASG

Question 31

Which load balancer would I use if I wanted to deploy, scale and manage a fleet of third party network virtual appliances in AWS, and if I wanted all traffic to my network to go through:
* firewalls
* intrusion detection and prevention systems
* deep packet inspection systems
* payload modification

Answer 31

Gateway Load Balancer

Section 7: AWS Fundamentals ELB + ASG

Question 32

How do you ensure a client (person, usually lol) is able to log in, close a session, start a new session and still be logged in?

Answer 32

Implement sticky sessions (also called session affinity) so that a load balancer constistently routes a person to the same EC2 instance.

Section 7: AWS Fundamentals ELB + ASG

Question 33

These cookie types and names might be useful if you want to implement what?

Application-base Cookies
* Custom cookie
* Application Cookie (name AWSALBAPP)

Duration-based cookies
* Cookie generated by load balancer
* Cookie name is AWSALB for ALB’s, and AWSELB for CLB’s (classic load balancer, so probably not going to be tested on that).

don’t worry so much about the specifics of this card, just that it exists and they’re called sticky sessions. these concepts might come up again during cloud front lectures.

Answer 33

Sticky Sessions

Section 7: AWS Fundamentals ELB + ASG

Question 34

You have 2 instances (targets) in load balancer A and 8 in load balancer B. Say they’re in different availability zones (the two load balancers). Each of the 2 load balancers are receiving 50% of traffic, and the 10 total targets are each receiving 10% of traffic. How do these numbers add up and does this mean you’re using cross zone load balancing?

Answer 34

Yes. Without cross zone load balancing the two targets in load balancer A would each receive 25% of total traffic (aka, 50% of the 50% that load balancer A receives). The 8 instances in load balancer B would each receive 6.25 of total traffic (aka 1/8th of the 50% of traffic load balancer B gets). This is because without cross load balancing, each load balancer can only distribute traffic to targets in it’s own availability zone. However, with cross zone load balancing, load balancer A can send traffic to targets in it’s OWN availability zone AS WELL AS targets in the availability zone of load balancer B (and likewise, load balancer B can send traffic to targets in the availability zone of load balancer A).

Note: round robin(even distribution of requests) is the default distribution algorithm.

Section 7: AWS Fundamentals ELB + ASG

Question 35

In which of the following are cross zone load balancers enabled by default? Also, when are you charged for AZ data transfer?
* Application Load Balancer
* Network Load Balancer
* Gateway Load Balancer
* Classic Load Balancer

Answer 35

Application load balancers have cross zone load balancing enabled by default. This behavior can be turned off at the Target Group level. Having cross zone load balancers enabled by default also means that AWS is not going to be charging you for inter AZ data.

You are charged for data transferred across AZs if you enable cross zone load balancing on a network or gateway load balancer. Cross zone load balancing is turned off by default for those types of load balancers.

For some reason, you are not charged if you enable cross zone load balancing for a classic load balancer (cross zone load balancing is turned off by default ).You also don’t get charged if there are any data transfers between AZ

Section 7: AWS Fundamentals ELB + ASG

Question 36

True/False:
An SSL Certificate allows traffic between your clients and your load balancer to be encrypted in transit

Answer 36

True

Section 7: AWS Fundamentals ELB + ASG

Question 37

True/False
TLS refers to Transport Layer Security, which is the newer version. Currently, TLS are used more than SSL Certifications, but many people (including Steph) will still refer to TSL as SSL.

Answer 37

True

Section 7: AWS Fundamentals ELB + ASG

Question 38

Which of the following is false:

• A) Public SSL certs are issued by certificate authorities (godaddy comodo etc). Encrypted = green lock (or gray). SSL certs have an exp date that you set.
• B) Users send HTTPS traffic to your load balancer. Your load balancer sends traffic to your EC2 instances using HTTP over private VPC.
  *C) Load balancer uses an X.509 cert (SSL/TLS cert)
• D) You manage certs using ACM (AWS Certificate Manager). You cannot create/upload your own certs.

Answer 38

D is false. Yes, you can manage certs using ACM, BUT you CAN also create and upload your own certs.

To be clear, all the other bullet points are true.

Section 7: AWS Fundamentals ELB + ASG

Question 39

Which bullet point is false?
When you set an HTTPS listener onto your load balancer (i think? I really could be all wrong about this. In case it comes up in questions, go back to the Elastic Load Balancer - SSL Certificates lecture and try clearning things up there. )
* A) AWS specifies their own certificate by default
* B) You can add an optinal list of certs to support multiple domains
* C) Clients can use SNI (server name indication) to specify the hostname they reach
* D) Ability to specify a security policy to support older versions of SSL/TLS
* E) you can, if you want, use an older version of ssl to support older clients

Answer 39

A is False. AWS does not specify their own certificate by default. You MUST specify a default certificate.

To be clear, all the other bullet points are true.

Section 7: AWS Fundamentals ELB + ASG

Question 40

• “Server Name Indication, often abbreviated SNI, is an extension to TLS that allows multiple hostnames to be served over HTTPS from the same IP address.” (https://https.cio.gov/sni/).
• “SNI solves the problem of loading multiple SSL certificates onto one web server (to serve multiple websites)”.
• So here’s the True/False question:
  SNI requires the client indicates the hostname of the target server in the initial SSL handshake. The server then finds the correct certificate or returns the default one.

Answer 40

True. Note that currently for AWS this only works for ALB and NLB (newer generation) and CloundFront.

As a clarifier, it seems as though each site (examples: domain2.example.com and www.mysite.com) has it’s own SSL certificate.

Section 7: AWS Fundamentals ELB + ASG

Question 41

Please review the following SNI / ALB / Target Group flow:

A client/user says “I would like to go to www.mysite.com”. They send that request to your Application Load Balaner. Your ALB uses the hostname of the target server that you provided (www.mysite.com) to idenfity the correct SSL certificate. Then the ALB uses that SSL certificate to route you to the correct target group (that is, the target group that contains www.mysite.com)

Answer 41

:)

Section 7: AWS Fundamentals ELB + ASG

Question 42

True or False:
Both Application Load Balancer (V2) and Network Load Balancer uses
* multiple listeners with mult SSL CERTS
* SNI

Answer 42

True

Section 7: AWS Fundamentals ELB + ASG

Question 43

What is Elastic Load Balancing and what are the three types of load balancers that ELB are really being talked about/used when people say “ELB”?

Answer 43

The distrubtion of traffic. It’s reffering to Application Load Balancers, Network Load Balancers, and Gateway Load Balancers.

Section 7: AWS Fundamentals ELB + ASG

Question 44

What would I search for (in these lectures, elsewhere on the internet, etc) if I wanted to make it so that people could use HTTPS to get to my application load balancer’s domain name (aka site url)?. I feel like you mark this card as answered correctly or incorrectly based on whether you come with and successfully use a query to address the issue in question.

Answer 44

In the lectures, you’d search for Elastic Load Balancer – SSL Certificates. The search “how to enable https on my application load balancer aws” returned promising results (ex: https://docs.aws.amazon.com/elasticloadbalancing/latest/application/create-https-listener.html, titled “Create an HTTPS listener for your Application Load Balancer”).

Section 7: AWS Fundamentals ELB + ASG

Question 45

Deregistration Delay (called connection draining when you’re talking about classic load balancers).

Deregistration (or draining) is like the process of deregistering your instance before you actually terminate it (or allow it to be terminated). Why would you want to wait before you terminated an unhealthy or unused instance? Well, say you had people currently trying to makae small or large requests (example, perhaps a GET or an UPLOAD) to an instance that you wanted to bring down. You’d want their requests to be able to complete before the instance was terminated. To get your instance to wait to existing connections/requests to complete, you set a deregistration delay. While an instance is de-registering, new traffic is sent to your non-deregistering instances (in other words, new traffic is sent to your other instances). The default deregistration delay is 300 seconds, but you can set the delay anywhere from 0 to 3600 seconds. So, here’s a question: Would you want to set the deregistration delay to 0 seconds if your site contained the ability for people to upload things? Would you want to set the deregistration delay to 1 second, in the same situation?

Can come up in the exam (I only started writing down when Steph says that just now. I may continue this practice.)

Answer 45

No. 0 seconds would turn the deregistration delay off. 1 second would not be long enough, people could potentially be in the middle of an upload when your EC2 instance started shutting down! You’d definitely want a longer deregistration delay for uploads. I have no idea how long would be needed though. Probably it would depend on the usual max size of the upload. If it usually takes 1000 seconds to do the upload, you’d probably want the deregistration delay to some bigger number than that.

Section 7: AWS Fundamentals ELB + ASG

Question 46

True / False:
The (or ‘a’) goal of an Auto Scaling Group is to:
* Scale out to match an increased load
* Scale in to match a decreased load
* Ensure the number of EC2 instances is at or above our min number, while also being at or below our max number.
* Automatically registers any new auto scaling group generated instances to your load balancer
* recreates an EC2 instance if a previous one is terminated due to being unhealthy.
* ASGs are free (you only pay for the underlying EC2 instances.)

Answer 46

True

Section 7: AWS Fundamentals ELB + ASG

Question 47

True / False
Auto Scaling Groups can work with a Load Balancer

Answer 47

True

Section 7: AWS Fundamentals ELB + ASG

Question 48

True / False
Elastic Load Balancers can check the health of your EC2 instances.

Answer 48

True

Section 7: AWS Fundamentals ELB + ASG

Question 49

True / False, the following is a currently valid list of ASG attributes:
* A Launch template (AMI + Instance Type; EC2 User Data; EBS Volumes; Security Groups; SSH Key Pair; IAM Roles for your EC2 Instances; Network + Subnets info; load balancer info)
* Min size/ max size/ initial capacity

Answer 49

True. The reverse question is “what is the list of asg attributes” (things to consider/fill out when making an asg).

Section 7: AWS Fundamentals ELB + ASG

Question 50

True / False
* It’s possible to scale an ASG based on CloudWatch alarms.
* An Alarm monitors a metric (such as avg CPU)
* based on the alarm you can trigger the Auto Scaling Group to scale in or out using scale-out policies or scale-in policies.

Answer 50

True. The reverse questions are:
* What’s one aws way to determine when to scale an ASG?
* What does an alarm monitor?
* based on the alarm can you trigger the Auto Scaling Group to scale in or out using scale-out policies or scale-in policies?

Section 7: AWS Fundamentals ELB + ASG

Question 51

Auto Scaling Groups - Scaling Policies
Name the Scaling Policy Assocated with each bullet point. Also, idenfity which scaling policies are now considered dynamic (Now, as opposed to when the video tutorial was made. The video tutorial has a different version of which scaling policies are dynamic.)
* A) The simplest and easiest to set up. You would use this, for example, if you wanted the average CPU of the instances in your ASG to stay at around 40%.
* B) An example: When a CloudWatch alarm is triggered (example, CPU > 70%) then add two units (presumably, each unit is, or at least could be, an EC2 instance). When a CloudWatch alarm is triggered (example, CPU < 30%) then remove 1 unit.
* C) In this type of scaling, you anticipate scaling based on known usage patterns. For example: Increase the min capacity to 10 instances at 5pm on Fridays.
* D) Continuously forecast load and schedule scaling ahead based on built in analysis of historical usage trends.

Note, for this question Simple/Step is one answer, but AWS now seems to be considering Simple and Step as two different types of scaling policies.

Answer 51

A) Target Tracking Scaling
B) Simple / Step Scaling
C) Scheduled Actions
D) Predictive Scaling

Target Tracking scaling, Step scaling and Simple scaling are currently considered Dynamic Scaling Policies (that is, when you create a new Dynamic Scaling Policy, you have those three policy types as options. )

Section 7: AWS Fundamentals ELB + ASG

Question 52

The following are some good Metrics to scale on (when creating scaling policies for your auto scaling grou). What are the names/terms associated with each bullet pointed description:
* A) Average CPU usage accross instances
* B) make sure the number of requests per EC2 instances is stable

Answer 52

A) CPUUtiliziation (no idea if the space is supposed to be there. It’s missing (the space) in the slide)
B) RequestCountPerTarget (okay now I really think the spaces in CPUUtilization is supposed to be missing)

Section 7: AWS Fundamentals ELB + ASG.

Question 53

As it relates to Auto Scaling Groups and Scaling Cooldowns, when do you enter the cooldown period? What is the default length of time for a cooling period?

Answer 53

You enter the cooldown period after a scaling activity happens. The default cooling period is 300 seconds. During this time the ASG will not launch or terminate additional instances (this allows metrics to stabilize). Stephane’s advice is to use a ready-to-use AMI to reduce config time in order to serve requests more quickly and reduce the cooldown period (I suppose the implimication is that ready to use AMIs have smaller cooldown periods?)

Section 7: AWS Fundamentals ELB + ASG

Question 54

About Dynamic Scaling Policies, provide the name of each of the scaling policies described below:
* A) simplest and easiest to set up; example is that you want the average Auto Scaling Group CPU to stay around 40%
* B) When a CloudWatch alarm is triggered (ex CPU > 70%) then add 2 units; when a CloudWatch alarm is triggered (ex CPU < 30%), then remove 1 unit. You have to set up the CloudWatch alarms and how many units are impacted (and whether they’re added or removed)
* C) Anticipate a scaling based on known usage patterns; example is to increase the min capacity to 10 (units) at 5pm on Fridays
* D) use historical load data to continuously forecast and schedule scaling ahead

Answer 54

A) Target Tracking Scaling
B) Simple / Step Scaling
C) Scheduled Actions
D) Predicitive Scaling

Section 7: AWS Fundamentals ELB + ASG. Yes, just noticed this card is sort of a duplicate, but I might just keep both. Or remove the other card, as I might like this one better.

Question 55

On the subject of Auto Scaling Groups and Scaling Policies, what are three good metrics to scale on (list excludes custom metrics that you push using CloudWatch).

Answer 55

• CPU utilization (avg CPU utilization accross instances)
• RequestCountPerTarget: to make sure the number of requests per EC2 instance is stable
• Average Network In/Out (ex you know you’re going to get a lot of uploads or downloads happening, like so many that it’ll cause issues, so you scale in or out based on the average network in (upload, I assume) or out (download, I assume))

Section 7: AWS Fundamentals ELB + ASG. Yes, just noticed this card is sort of a duplicate, but I might just keep both. Or remove the other card, as I might like this one better.

Question 56

What Auto Scaling Group feature do you call it when you update the launch template (say the user data or the AMI (Amazon Machine Image)) and then re-create all the EC2 instances?

Answer 56

Instance Refresh. Setting of minimum healthy percentage. Specify warm up time.

Section 7: AWS Fundamentals ELB + ASG

Question 57

Scaling an EC2 instance from r4.large to r4.xlarge is called _____?
A) Horizontal Scalability
B) Vertical Scalability

End of Section Quiz Questions

Answer 57

B) Vertical Scalability

Section 7: AWS Fundamentals ELB + ASG

Question 58

Running an pplication on an Auto Scaling Group that sclaes the number of EC2 instances in and out is called ____?
A) Vertical Scalability
B) Horizontal Scalability

End of Section Quiz Questions

Answer 58

B) Horizontal Scalability

Section 7: AWS Fundamentals ELB + ASG

Question 59

Elastic Load Balancers provide a …….?
A) static IPv4 we can use in our application
B) static DNS name we can use in our application
C) static IPV6 we can use in our application

End of Section Quiz Questions

Answer 59

B) Elastic Load Balancers provide a static DNS name we can use in our application.

Clarifying Note: Only Network Load Balanacers provide both static DNS name and static IP. Application Load Balancers provide a static DNS name but do NOT provide a static IP. The reason DNSes are static is because AWS wants your ELB to be accessible using a statuc endpoint, even if the underlying AWS managed infrastrcuture is changed.

Section 7: AWS Fundamentals ELB + ASG

Question 60

You are running a ebsite on 10 EC2 instances fronted by an Elastic Load Balancer. Your users are complaining about the fact that the website always asks them to re-authenticate when they are moving between website pages. You are puzzled because it’s working just fine on your machine and in the dev env. with 1EC2 instance. What could be the reason?
A) The ELB does not have Sticky Sessions enabled.
B) Your website must have an issue when hosted on multiple EC2 instances.
C) The EC2 instances log out users as they can’t see their IP addresses, instead, they receive ELB IP addresses.

End of Section Quiz Questions

Answer 60

A) The ELB does not have Sticky Sessions enabled.

Clarifying Note: ELB Sticky Session feature ensures traffic for the same client is always redirected to the same target (e.g., EC2 instance). This helps ensure that the client does not lose their session data.

Section 7: AWS Fundamentals ELB + ASG

Question 61

You are using an Application Load Balancer to distribute traffic to your website hosted on EC2 instances. If turns out that your website only sees traffic cmoing from private IPv4 addresses which are in fact your ALB’s IP addresses. What should you do to get the IP address of clients connected to your website?
A) Modify your website’s frontend so that users send their IP in every request
B) Modify your website’s backend to get the client IP address from X-Forwarded-For header
C) Modify your website’s backend to get the client IP address from X-Forwarded-Port header
D) Modify your website’s backend to get the client IP address from X-Forwarded-Proto header

End of Section Quiz Questions

Answer 61

B) Modify your website’s backend to get the client IP address from X-Forwarded-For header.

Clarifying Note: When using an Applicatin Load Balancer to distribute traffic to your EC2 instances, the IP address you’ll receive requests from will be the ALB’s private IP address. To get the client’s IP address, ALB adds an additional header called X-Forwarded-For that contains the client’s IP address.

Section 7: AWS Fundamentals ELB + ASG

Question 62

You hosted an application on aset of EC2 instances fronted by an Elastic Load Balancer. A wek later, users begin complaining that sometimes the application just doesn’t work. You investigate the isssue and found that some EC2 instances crash from time to time. What should you do to protect users from connecting to the EC2 instances that are crashing?
A) Enable ELB Stickiness
B) Enable SSL Termination
C) Enable ELB Health Checks
D) Enable Cross-Zone Load Balancing

End of Section Quiz Questions

Answer 62

C) Enable ELB Health Checks

Section 7: AWS Fundamentals ELB + ASG

Question 63

You are working as a Solutions Architect for a company and you are required to design an architecture for a high-performance, low-latency application that will receive millions of requests per second Which type of Elastic Load Balancer should you choose?
A) Application Load Balancer
B) Classic Load Balancer
C) Network Load Balancer

End of Section Quiz Questions

Answer 63

C) Network Load Balancer

Section 7: AWS Fundamentals ELB + ASG

Question 64

Application Load Balancers support the following protocols, EXCEPT:
A) HTTP
B) HTTPS
C) WebSocket
D) TCP

End of Section Quiz Questions

Answer 64

D) TCP

Clarifying Note: Network Load Balancers support both TCP and UDP protocols.

Anna’s clarifying note: After trying to ask the internet, here’s what it sounds like. All (probably all) HTTP/HTTPS uses TCP. It’s kind of like the HTTP connection is created and then closed with TCP. However, it seems as though it is possible to want to create/use a TCP client that does not contain any HTTP usage. (see ni.com/docs/en-US/bundle/labview/page/creating-a-tcp-client.html)

Section 7: AWS Fundamentals ELB + ASG

Question 65

Application Load Balancers can route traffic to different Target Groups based on the following, EXCEPT:
A) Hostname
B) Client’s Location (Geography)
C) Request URL Path
D) Source IP Address

End of Section Quiz Questions

Answer 65

B) Client’s Location (Geography)

Clarifying Note: ALBs can route traffic to different Target Groups based on URL Path, Hostname, HTTP Headers (of which, Source IP Address is one, though it’s often called X-Forwarded-For by the time it gets to the target (target example: EC2 instance)) and Query Strings

Section 7: AWS Fundamentals ELB + ASG

Question 66

Registered targets in a Target Group for an Application Load Balancer can be one of the following, EXCEPT:
A) Network Load Balancer
B) Lambda Functions
C) Private IP Addresses
D) EC2 Instances

End of Section Quiz Questions

Answer 66

A) Network Load Balancer

Section 7: AWS Fundamentals ELB + ASG

Question 67

For compliance purposes, you would like to expose a fixed static IP address to your end-users so that they can write firewall rules that will be stable and approved by regulators. What type of Elastic Load Balancer would you choose?
A) Application Load Balancer with an Elastic IP attached to it
B) Network Load Balancer
C) Classic Load Balancer

End of Section Quiz Questions

Answer 67

B) Network Load Balancer

Clarifying Note: Netowrk Load Balancer has one static IP address per AZ and you can attach an Elastic IP address to it. Application Load Balancers and Classic Load Blaancers have a static DNS name.

Section 7: AWS Fundamentals ELB + ASG

Question 68

You want to create a custom application-based cookie in your APplicatiorn Load Balancer. Which of the following can you use as a cookie name?
A) AWSALBAPP
B) AWSALBTG
C) APPUSERC
D) AWSALB

End of Section Quiz Questions

Answer 68

C) APPUSERC

Clarifying Note: AWSALB, AWSALBAPP and AWSALBTG are cookie names reserved by the ELB.

Section 7: AWS Fundamentals ELB + ASG

Question 69

You have a Network Load Balancer that distributes traffic across a set of EC2 instances in us-east-1. You have 2 EC2 instances in us-east-1b AZ and 5 EC2 instances in us-east-1e AZ. You have noticed that the CPU utilization is higher in teh EC2 instances in us-east-1b AZ. After more investigation, you noticed that hte traffic is equally distributed across the two AZs. How would you solve the problem?
A) Enable Sticky Sessions
B) Enable Cross-Zone Load Balancing
C) Enable ELB Health Checks
D) Enable SSL Termination

End of Section Quiz Questions

Answer 69

B) Enable Cross-Zone Load Balancing

Clarifying Note: When Cross-Zone Load Balancing is enabled, ELB distrubutes traffic evenly across all registered EC2 instances in all AZs.

Section 7: AWS Fundamentals ELB + ASG

Question 70

Which feature in both Application Load Balancers and Netwoek Load Balancers allows you to loda multiple SSL certificates on one listener?
A) Server Name Indication (SNI)
B) TLS Termination
C) Host Headers
D) SSL Security Policies

End of Section Quiz Questions

Answer 70

A) Server Name Inidication (SNI)

Section 7: AWS Fundamentals ELB + ASG

Question 71

You have an Application Load Balancer that is configured to redirect traffic to 3 Target Groups based on teh following hostnames: users.example.com, api.external.example.com, and checkout.example.com. You would like to configure HTTPS for each of these hostnames. How do you configure the ALB to make this work?
A) Use an HTTP to HTTPS redirect rule
B) User a security group SSL certificate
C) Use Server Name Indication (SNI)

End of Section Quiz Questions

Answer 71

C) Use Server Name Indication (SNI)

Clarifying Note: Server Name Indication (SNI) allows you to expose multiple HTTPS applications each with its own SSL certificate on the same listener. Read more here: https://aws.amazon.com/blogs/aws/new-application-load-balancer-sni/

Section 7: AWS Fundamentals ELB + ASG

Question 72

You have an application on a set of EC2 instances managed by an Auto Scaling Group for which you configured both a desired and a maximum capacity of 3. Also, you ahve created a CloudWatch Alarm that is configured to scale out your ASG when CPU Utiliziation reaches 60%. Your application suddenly received huge traffic and is now running at 80% CPU Utiliziation. What will happen?
A) The desired capacity will go up to 4 and the maximum capacity will stay at 3
B) Nothing
C) The desired capacity will go up to 4 and the maximum capacity will stay at 4

End of Section Quiz Questions

Answer 72

B) Nothing.

Clarifying Note: The Auto Scaling Group can’t go over the maximum capacity (you configured) during scale-out events.

Section 7: AWS Fundamentals ELB + ASG

Question 73

You have an Auto Scaling Group fronted by an Application Load Balancer. You have configured the ASG to use ALB Health Checks, then one EC2 instance has just been reported unhealthy. What will happen to the EC2 instance.
A) The ASG will keep the instance running and re-start the application
B) The ASG will detach the EC2 instance and leave it running
C) The ASG will terminate the EC2 instance

End of Section Quiz Questions

Answer 73

C) The ASG will terminate the EC2 instance

Clarifying Note: You can configure the Auto Scaling Group to determine the EC2 instance’s health based on Application Load Balancer Health Checks instead of EC2 Status Checks (default). When an EC2 instance fails the ALB Health Checks, it’s marked unhealthy and will be terminated while the ASG launches a new EC2 instance.

Section 7: AWS Fundamentals ELB + ASG

Question 74

Your boss asked you to scale your Auto Scaling Group based on the number of requests per minute your application makes to your database. What should you do?
A) You politely tell him it’s impossible
B) Create a CloudWatch custom metric then create a CloudWatch Alarm on this metric to scale your ASG
C) Enable Detailed Monitoring then create a CloudWatch Alarm to scale your ASG

End of Section Quiz Questions

Answer 74

B) Create a CloudWatch custom metric then create a CloudWatch Alarm on this metric to scale your ASG

Clarifying Note: There’s no CloudWatch metric for “requests per minute” for backend-to-database connections. You need to create a CloudWatch Custom Metric, then create a CloudWatch Alarm.

Section 7: AWS Fundamentals ELB + ASG

Question 75

An application is deployed with an Application Load Balancer and an Auto Scaling Group. Currently, you manually scale the ASG and you would like to define a Scaling Policy that will ensure the average number of connections to your EC2 instances is around 1000. Which Scaling Policy should you use?
A) Simple Scaling Policy
B) Step Scaling Policy
C) Scheduled Scaling Policy
D) Target Tracking Policy

End of Section Quiz Questions

Answer 75

D) Target Tracking Policy

Section 7: AWS Fundamentals ELB + ASG

Question 76

Your application hosted on EC2 instances managed by an Auto Scaling Group suddenly receives a spike in traffic which triggers your ASG to scale out and a new EC2 instance has been luanched. The traffic continuously increases but the ASG doesn’t launch any new EC2 instance immediately but after 5 minutes. What is a possible cause for this behavior?
A) Cooldown Period
B) Lifecycle Hooks
C) Target Tracking Policy
D) Launch Template

End of Section Quiz Questions

Answer 76

A) Cooldown Period

Clarifying Note: For each Auto Scaling Group, there’s a Cooldown Period after each scaling activity. In this period, the ASG doesn’t luanch or terminate EC2 instances. This gives time for metrics to stabilize. The default value for the Cooldown Period is 300 seconds (5 minutes).

Section 7: AWS Fundamentals ELB + ASG

Question 77

Auto Scaling Group Predictive Scaling Policy Metrics:
* A) Uses the total CPU to create the load forecast and the average CPU to define your target utilization
* B) Uses the total number of butes received to create the laod forecast and the average number of bytes received to define your target utilization
* C) Uses the total number of butes sent to create the load forecast and the average number of bytes send to define your target utilization
* D) Uses the total request count to create the laod forecast and theaverage number of requests per target to define your target utilization
* E) Choose your own load and scaling metrics. For predictive scaling to work effectively, the scaling metric and load metric must be strongly correlated.

Answer 77

• A) CPU Utilization
• B) Network in (bytes)
• C) Network out (bytes)
• D) Application Load Balancer request count
• E) Custom metric pair

Section 7: AWS Fundamentals ELB + ASG

Question 78

You have an app for which you want a zonal static IP address (ex: 12.333.444.555) (static IP address per availability zone, which might go towards explaining why aws.com might be showing as us.aws.com or aus.aws.com). You also want PrivateLink. You also want advanced request routing features based on parameters like HTTP headers and methods, query string, host and path based routing. What load balancer(s) do you use?

Answer 78

Application load balancer behind a network load balancer. That is, your nlb has as it’s target an alb. Traffic goes from clients to your nlb which routes traffic to your alb (don’t know if you’d ever want more than one). The nlb gets you PrivateLink and the static IP address (btw, I think those can only be zonal, so if someone says zonal they just mean regular static IP addresses and it turns out those are zone specific, at least with aws idk I could be wrong)