AWS Loadbalancer and Autoscaling Flashcards

1
Q

What types of load balancers can you have in AWS?

A
  • Classic LB
  • Network NLB
  • Application ALB
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2
Q

Is an ELB, highly available?

A

Yes, it is created in a region and across multiple AZ’s in the region.

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3
Q

Dump this

A

Dump this

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4
Q

How does AWS create a logical ELB in AWS?

A

The logical LB is created from several nodes distributed into the available AZ’s. As you see each of these nodes has a separate public IP, to enable it to seems as if you are connecting to a single endpoint of the ELB, AWS creates a URL they you connect to when accessing the ELB, this URL will return all the ELBs of the ELBs to you. This causes an issue in that the load may not be distributed equally depending on how my instances you have in each AZ, to get around this the ELB has cross zones replication, in classic LB you had to enable it, newer LBs have it enabled by default.

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5
Q

When using an ELB with an autoscaling group, what has the autoscaling group to do as it adds and removes nodes?

A

The autoscaling group has to add and remove the registration of the nodes with the ELB target group.

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6
Q

Can you use an ELB without Autoscaling group?

A

Yes, you just have to register the instances with the ELB target group.

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7
Q

What is an ELB target group used for?

A

A target group is used to group instances the ELB will distribute traffic to.

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8
Q

Should, I use classic LB?

A

No, they are moving away from this LB, you should use NLB or ALB.

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9
Q

What transports do classic LB support?

A

TCP, SSL, HTTP, HTTS

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10
Q

In a classic LB do I get a security group for my ELB?

A

Yes, when you create an ELB you create or assign a security group.

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11
Q

What are ELB health checks?

A

ELB performs a check on the backend instance, by performing one of the following,

  • Checking the instance status
  • Sending an HTTP/HTTPs request and checking th response code.
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12
Q

If the software running on my webserver holds state and requires thet any returning request be sent to the same server node, is this possible with ELB

A

Use ELB client sticky session, you have two options,

  • LB generate cookies
  • Application generated cookies
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13
Q

I the classic ELB a layer 7 device?

A

No

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14
Q

What is an ALB?

A

It is an application load balancer and operates at layer 7 with a wider set of services,

  • EC2
  • Contaners
  • Lambda
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15
Q

I require the ability to route HTTP traffic based on the path, what LB should I use?

A

ALB

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16
Q

I require an LB that can route based on path and can be internal facing, what type of ELB should I choose?

A

ALB

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17
Q

I require an LB that will work for both IPv4 and IPv6, what ELB should I use?

A

ALB

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18
Q

What is the target group?

A

It is a collection of instances.

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19
Q

I am using a lambda function and I wnat to have an LB in front of it so I can control the traffic going to different function and also to enable blue/green deployments, what is my best option?

A

Use an AL, ALB support Lambda functions.

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20
Q

Does NLB support WebSockets?

A

No, you will need an ALB

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21
Q

I have a multiple application that needs an LB, what LB can I used the also can do rooting at L7?

A

You cna use the ALB, it enables you to route based on pat and domain.

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22
Q

Can I use multiple certs on an ALB?

A

Yes.

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23
Q

I want to understand who is hitting my LB, how and I architect this?

A

LB’s support access logs and enable you to capture th logs.

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24
Q

I want to understand who is hitting my LB, how and I architect this?

A

LB’s support access logs and enable you to capture the logs.

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25
Q

I wnat to redirect on my LB, is this possible?

A

Yes you can do it on your ALB

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26
Q

What is a network LB?

A

It is an LB that operates at L4 or the OSI model.

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27
Q

if I need extreme performance LB should I choose NLB or ALB?

A

NLB as it is not processing the incoming l7 traffic and operating at l4 they can deal with high volumes of traffic.

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28
Q

I need an LB to support static IP, will an ALB work for me?

A

No ALB only support DSN, you need an NLB for a static IP

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29
Q

I need an end to end encryption (TLS) but I need lB to load balance across my nodes, should I have an ALB?

A

No, ALBs do not pass through the connection a NLB is operating at the TCP layer and the encryption will be passed straight through to the host.

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30
Q

Can I have an NLB for internal load balancing?

A

Yes.

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31
Q

I wnat to authenticate users using OpenID for my application but I do not what to modify my application, how could i do this?.

A

You cna use an ALB, it supports authentication of users by OpenID.

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32
Q

I wnat to authenticate users using OpenID for my application but I do not what to modify my application, how could I do this?.

A

You cna use an ALB, it supports authentication of users by OpenID.

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33
Q

I wnat to authenticate users using IdP like FB, Amazon, Google and cognito, is it possible to auth using the ALB?

A

Yes

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34
Q

I wnat to authenticate users using IdP SAML, LDAP, MS AD, Google and cognito, is it possible to auth using the ALB?

A

Yes

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35
Q

Dose ALB or NLB support UDP

A

No

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36
Q

I need to create a load balancer with autoscaling in the backend, how cna I do this?

A
  • Create a Launch template
  • Create an autoscaling group and use Launch config
  • Create an ALB as this works best for our web type workload, we will also as part of this create a target group.
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37
Q

Do we create an ELB with a security group?

A

Yes, 100%, each ELB gets deployed as an ENI in the VPC and there is a security group applied to the interface.

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38
Q

I have deployed an ALB, do I get a single IP to send traffic to?

A

No, each LB is deployed in an AZ and depending on the number of AZs and the load, you will get back one IP for each LB making up the ELB.

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39
Q

What is an NLB used for?

A

L4 traffic (L7 traffic is passed through untouched.

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40
Q

How do health checks work on the ELB?

A

You set up the health check to be HTTP, TCP, HTTPS or SSL and the health checker will send out pings to make sure the node is working, If the node is not working it will be taken out of the pool of good node the ELB sends traffic to.

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41
Q

What are the two types of health checks you can set on an Autoscaling group?

A

ELB (Hecks are pinged)

EC2 (Checks are on the status of the instance)

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42
Q

I have nodes with issues of performance for HTTPS, I did not have these issues when I used HTTP, what options do I have?

A

HTTPs offload, ALB supports HTTPs offload.

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43
Q

I wnat to use HTTPs offloading with my LB, where can I store the cert?

A

AWS Cert Manager

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44
Q

What are the option available for giving an LB a cert?

A
  • Upload
  • IAM Cert
  • ACM cert
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45
Q

When the ELB is integrated with autoscaling group and the health check fails, what happens to the instance?

A

Instances are terminated and recreated if they fail the health check.

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46
Q

I wnat to add my own domain and subdomain to an ELB, how can I do this?

A

You need to set up a zone in Route53 and create a CNANE record to point to the ELB’s URL.

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47
Q

What services can the ALB support, traditionally it supported EC2?

A
  • Lambda

- EKS

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48
Q

For ALB’s what are the actions used for?

A

They allow you to define,

  • Redirect to
  • Forwared to
  • Return a fixed response
  • Authenticate
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49
Q

With an NLB can you have a static IP for the front-end?

A

Yes

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50
Q

Does an NLB support UDP?

A

No

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51
Q

With an NLB can I LB to IP’s outside the VPC?

A

Yes

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52
Q

What is WAF sandwich?

A

It is where you place a WAF between two LBs

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53
Q

What is dynamic scaling for an autoscaling group?

A

This is where AS adjusts the number of EC2 instances or ECS tasks to ensure the CPU is kept below 75%

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54
Q

What is predictive scaling?

A

This is where ML is used to predict/forecast the required capacity for EC2 and ECS and will adjust resources based on the forecast.

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55
Q

I want to use autoscaling and scale on a metric, is using 5m intervals OK?

A

No, you are better to use a finer resolution of 1min, scaling will react faster to changing workload.

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56
Q

What are the two configuration templates used by Autoscaling?

A
  • Launch config

- Launch template

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57
Q

My workload is variable and also can deal with been stopped at any point in time, I want to get to the lowest price point, how can I achieve this?

A

You can use spot instances

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58
Q

I have a steady baseline that I know will be there for up to 3 years for my instances, I also have a verable workload, how can I optimize for cost?

A

You can use Auto Scale Group, to scale your workload and use fleet too with reserved and spot.

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59
Q

What are lifecycle hooks?

A

In AustoScaling you can configure a lifecycle hook, it will pause the instance on start or terminate and triggered a CloudWatch event, with the CW event you can select to take many different actions using services like SNS, Lambda, etc.

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60
Q

I wnat to be notified when instances launch or terminate, how cna I do this?

A

Using notifications?

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61
Q

I need to take an action as an instance is launched, this action is to register the instances in a CDMB, the instance must not become active until it is registered, how can I do this?

A

You cna use AutoScaling Lifecycle hooks

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62
Q

How is CloudWatch used with AutoScaling?

A

You get to create CloudWatch alarms that get triggered by the metrics coming form ASG, this enables you to scale up or down your instances.

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63
Q

What is AMI baking?

A

This is where we bake in the AMI all software we need.

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64
Q

Can I change the launcher configuration?

A

No

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65
Q

By default how is an autoscaling group using its health checks?

A

By default, the autoscaling group will use the EC2 status to understand when it will terminate an instance.

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66
Q

By default how is an autoscaling group using its health checks?

A

By default, the autoscaling group will use the EC2 status to understand when it will terminate and replace an instance.

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67
Q

What is the health check grace period?

A

This is the amount of time given before health checks start, this enables the software on the EC2 instance to settle.

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68
Q

What are the scaling types?

A
  • Maintain: You maintain x number of instances
  • Manual: You set what you want
  • Schedule: You set a period you wnat to have x instances
  • Dynamic: You respond to the load.
69
Q

What is a scaling policy?

A

This is a policy that defines how to scale the instances, you have,

  • Target tracking, scale based on the predefined metric
  • Simple scaling,
  • Step scaling,
70
Q

Can you pause and autoscaling group form scaling?

A

Yes

71
Q

I have 3 AZ’s with each AZ having 3 instances, for my application to work correctly I need 9instances, I wnat to ensure if I lose an AZ that I still handle the workload, how can I do this?

A

Put all instance in a scale group across the 3 AZs and reserve 3 instances. The reserved instance will ensure you can spin up instances when needed.

72
Q

I am using a TLS with a network load balancer and I want to ensure the backend application will get the clients IP?

A

When TLS is terminated on the NLB, the client is preserved.

73
Q

What are the autoscaling group options for scaling?

A
  • ELB request could
  • CPU
  • IN bytes
  • OUT bytes
  • You can also set up cloudwatch alarms to trigger scaling policy.
74
Q

My application has a performance counter thet I wnat to use to scale up and down the number of instances, how can I do this?

A

You cna use cloudwatch to capture the performance counter, using custom metrics. Set up two clouds what alarms, up and down alarms and have the alarms trigger autoscaling policies in an autoscaling group.

75
Q

I have instances distributed across zones using an autoscaling group, how can I have an ELB send traffic to all instances?

A

Enable cross AZ

76
Q

Is the ELC controlling the autoscaling group?

A

No, the autoscaling group job is to scale, this cna be based on default value such as the CPU, ELB counted requests, bytes in/out.

77
Q

Is an ELB a single instance?

A

No, ELBs are created in the AZ used by your application, the number of ELB’s depend on the load, AWS scales up as required. You can only use DNS to access the ELB as there are many instances with many addressed, do the DNS ‘A’ record will contain all the IP’s of the ELBs.

78
Q

How is the incoming ELB load distributed to each of the single ELB nodes?

A

ELB used DNS round-robin.

79
Q

What is cross-zone loadbalacng?

A

This is where traffic is distributed to the backends evenly across all AZ’s

80
Q

Which of the two load balancer types support SSL offload, ALB, Network LB or both?

A

Both support SSL offload

81
Q

Which of the two load balancer types support query string parameter-based routing offload, ALB, Network LB or both?

A

ALB

82
Q

Explain what Server Name Indication (SNI) is and how it is used?

A

SNI is an extension to the TLS/SSL in 2003 and it enables the browser (client) to add the domain name in the request. This request is used by the server to identify and select the cert to use. In AWS NLB and ALB is used to select the correct cert to use.

83
Q

Using Server Name Indication (SNI), what is the max number of certs you can use with ELB?

A

25

84
Q

Is HTTP/2 supported by ALB?

A

Yes

85
Q

What are the methods of routing supported by ALB?

A
  • Query string
  • Header based routing
  • Method based routing
  • Host-based routing
  • Path-based routing
  • IP/CIDR based routing
86
Q

Are lambda functions supported by ALB?

A

Yes, you can use the Lambda as a target for the ALB.

87
Q

Is private link supported for ALB?

A

No, privatelink is only supported by NLB.

88
Q

I have a service, presented through a web page using a web server, I want to privately share this with my customer and where my customer are using AWS VPC. What options do I have?

A

You can create an NLB and make the NLB available into your customer VPC using privatelink.

89
Q

I am using both ALB and ELBs and I wnat to improve my visibility into who and where my customers and possibly bad actors are accessing my services behind the ELBS, what options do I have?

A

Both ELB types support access logs, there can be pushed to S3 and Atena can Quicksight can be used to better understand using Atena queries and a quick sight to visualize.

90
Q

What is Connection draining?

A

It means that all request will be completed before deregistering happens.

91
Q

Are multiple listening ports supported on the ELB?

A

Yes

92
Q

Explain Host-Based routing in the context of ALB?

A

Host-based routing is when you want to deliver say api.keith.com and www.keith.com to the same server endpoint and have the server route the request to the appropriate app.

93
Q

Explain Path-Based routing in the context of ALB?

A

This is where you are routing incoming HTTP request based on for example /v1 and sat /v2 to different apps on the webserver.

94
Q

Explain Header-Based routing in the context of ALB?

A

This is where you are using values in the HTTP header to route incoming HTTP requests, for example, you may have a cookie in the header and you may be rooting based on the cookie.

95
Q

Are sticky sessions available in NLB’s?

A

No

96
Q

I have an IoT device and it talks to the set of web services behind a load balancer, currently running on-prem. I wnat to make to AWS and I need to select an ELB, each IoT device has a hard code dIP and can not resolve a DNS name, should I select an ALB?

A

You have to use an NLB as it can have static IP, this means the IoT device with it hardcoded IP can connect to this static IP.

97
Q

I need to select an ELB thet will preserve the source IP, what ELB will I select?

A

NLB as it supports the preservation of the source IP, ALB does not.

98
Q

I have an on-prem web server thet is public-facing, I wnat it to be load balanced by an ALB temporarily as part of a transition of the on-prem solution to AWS, is this possible?

A

Yes, ELB support using IP’s as a target, this means thet once the AWS ELB can see the ending IP ad in it is public-facing, you can load balance to it.

99
Q

What is Source IP address CIDR-based routing?

A

This is where the ELB will route the incoming request based on the IP or CIDR range.

100
Q

I am using Amazon EC2 Container Service (ECS) and I want to load balance for my containers, do I need a 3rd part load balancer for my solution?

A

No ALB supports Amazon EC2 Container Service (ECS) as a target.

101
Q

What is HTTP/2 Support, explain?

A

HTTP/2 is a new version of the HyperText Transfer Protocol (HTTP) that uses a single, multiplexed connection to allow multiple requests to be sent on the same connection. It also compresses header data before sending it out in binary format and supports SSL connections to clients.

102
Q

Can I used IPv6 on an NLB?

A

No, NLB does not support IPv6, ALB have support for IPv6.

103
Q

How cna I monitor the performance of my ELB?

A

Using cloud watch.

104
Q

I am using ALB and I need to be able to trace an incoming HTTP requets across service, what option do I have?

A

x-ray is one option, but as this is focused more on ELB, the answer would be ‘request tracing’. The Application Load Balancer injects a new custom identifier “X-Amzn-Trace-Id” HTTP header on all requests coming into the load balancer. Request tracing allows you to track a request by its unique ID as the request makes its way across various services that make up your websites and distributed applications. You can use the unique trace identifier to uncover any performance or timing issues in your application stack at the granularity of an individual request

105
Q

What is the target group?

A

This is a set of instances the ELB is going to route to.

106
Q

I have a web site with ALB, I need to add the ability to log in using OpenID, what is my best option?

A

ALB has the ability to enable you to auth users using a number of different methods. OpenID is one such method.

107
Q

What authentication methods does ALB support?

A
  • OpenID
  • Socail, FB, Google, Amazon, Cognito
  • SAML
  • LDAP
  • Microsoft AD
108
Q

I have a web site with ALB, I need to add the ability to log in using Mic Microsoft AD to auth, what is my best option?

A

ALB has the ability to enable you to auth users using a number of different methods. Microsoft AD is one such method.

109
Q

I need an internal load balancer on my VPC that is not external facing, what are my options?

A

You can use ELB (ALB, NLB), both support internal VPC support.

110
Q

I have tow ALB in two VPC in tow different regions, how can I load balance between the regions, is this an option on the ALB or is there other AWS service options available?

A

You would use Route53 and weighted routing.

111
Q

When I am using an ALB and Route 53, what is the record type I need to be using to reference the ALB?

A

A CANONICAL record, this record type points at the ALB DNS name.

112
Q

I require IPv6 load balancing, what is the correct ELB type to select?

A

ALB supports IPv6 in a dual-stack mode

113
Q

I am using an ELB and what to ensure only port 80 and 443 are open, what options do I have?

A

You can use a security group with the ALB to ensure only 80 and 443 are open.

114
Q

I have deployed a new version of my application on new EC2 servers instances. This new application is under the path /v2 the existing application was under the path v1. Current /v1 app is behind an AWS ALB. How can I send 50% of the traffic to the new /v2 application?

A
  • Add a new target group to the existing ALB

- Add a new listener rule to split traffic by 50% to a new target group.

115
Q

How can I secure the traffic coming to the ELB from DDOS attacks?

A
  • Shield basic is already in place when you use the ALB, you can add shield advance and this will add L7 protection.
116
Q

How can I secure the traffic coming to the ELB from SQL Injection attacks?

A

You can add a WAF.

117
Q

How can I further increase the security of my ELB?

A

Use GuardDuty, GD will analyse the VPC flow logs for threats,

118
Q

My team has just started deploying their application on EKS and one of the requirements is to use an application load balancer, what options do I have?

A

The AWS application load balancer (ALB) can be used with AKS

119
Q

Is it the ELB or the Aust Scaling Group that adds instances into the target group?

A

It is the AutoScaling group, you register the target group with the autoscaling group and it adds the instances to the target.

120
Q

I have two versions of my application behind an ALB, can I add two certs to the ALB?

A

Yes you can add many certs

121
Q

Do NLB support HTTP/2?

A

No, but an ALB dose?

122
Q

The ALB supports HTTP/2, explain the features of HTTP/2?

A
  • Multiplexed requests, the ability to open a single connection and send many requests at the same time.
123
Q

I need an L4 (TCP) load balancer, what is my best option?

A

Use a network load balancer, this is operating at L4 (TCP).

124
Q

I require a static IP to be used with my load balancer, should I use an ALB?

A

ALB only support DNS, Network load balancer can have static IP’s.

125
Q

When would I have a Network load balancer?

A
  • Ultra-low latency
  • L4
  • App need to have direct access by client
  • Preserving client IP.
126
Q

For NLB’s what type of listeners so they use?

A

TCP,

127
Q

For NLB’s is the connection terminated at the NLB?

A

No, the connection is terminated at the web application.

128
Q

I require an uninterrupted end to end encryption when used a load balancer, what is my bets option, I am thinking of using an ALB?

A

ALB is not suitable as it will terminalte the encrypted connection at the ALB, the option is to use an NLB where the conenction is terminated at the server application.

129
Q

I require an uninterrupted end to end encryption when used a load balancer, what is my best option, I am thinking of using an ALB?

A

ALB is not suitable as it will terminate the encrypted connection at the ALB, the option is to use an NLB where the connection is terminated at the server application.

130
Q

I am using autoscaling and I what to launch instances as fast a possible, what is my best option?

A

Use AMI baking as bootstrapping is slower

131
Q

Which is fastest and why when booting instance in an autoscaling group?

A

Use AMI baking as it bakes in the software and apps and no need to deploy at software and config at boot, unlike bootstrapping that will install and configure the software at boot time.

132
Q

I am using the AWS AustoScaling Group with a load balancer, my application can be terminated without any issues at any point. I wnat to get the lowest price possible. What is my best option?

A

Create an autoscaling group with a launch configuration where you use spot instances.

133
Q

I need to edit a launch configuration, what are the steps involved?

A

You can not change a launch configuration

134
Q

I need to edit a launch template, is this possible and if so explain?

A

You can edit a launch template when you do the version id increments and you can reference any of the previous or current version of the launch template.

135
Q

What is the health check grate period in reference to the auto-scaling group?

A

It is the period of time an autoscaling group will what after instances are launched before health checks are sent to the instance.

136
Q

What an instance terminates for some reason, what action will the Autoscaling group take for thet instance?

A

It will replace the instance.

137
Q

What are Austscaling group scaling policies?

A

They control how the autoscaling group scales,

  • Step scaling enables you to react more aggressively to larger changes
  • The simple scaling policy enables you to track say CPU and the ASG will try to add instance to keep the CPU at say 50%
138
Q

Each day between 6aqm and 9 am we see a large load on our auto-scaled instance group, one issue we have is the reaction time to getting new instances is slow to start with. What option do we have?

A

With auto-scaling, you can have scheduled scaling where we can up the number of instances for the time period required.

139
Q

I what to stop the auto-scaling group from making any further changed during a maintenance window, is this possible and if so how?

A

You can edit the auto-scaling group and set the suspend processes to stop the ASG from changing during the maintenance window.

140
Q

I always need a min of 66% of my instances running for my application to work properly. what is the best option?

  • 9 instances in 3 AZs
  • 6 instances in 2 AZs
  • 9 instances in 1 AZs
A
You need to think about two things here,
- Capacity when running at normal
- Min capacity the app cna run on
Answer is,
- 9 instances in 3 AZs
141
Q

I have 9 instances split into 3 instances in 3 AZ’s, my app cna run on 66% of the overall capacity. what would I need to do to ensure application stays running?

A

You have to reserve instance capacity in all 3 AZs as when the auto-scaling group terminates an instance with my not be able to create one without capacity been reserved.

142
Q

My application can never have a situation where eis is below 9 instances, what is my best option,

  • 9 instances in 3 AZs
  • 6 instances in 2 AZs
  • 9 instances in 1 AZs
  • 12 instance in 4 AZ’s
A

Here you need to focus on again what is the min capacity needed, it is 9 instance but in this case, you need 9 instances s100% of the time and if an AZ was to fail with just 9 instances you would drop below the 9 for a small period and this would not meet the requirement so you have to OVER PROVISION capacity. so 12 instances in 4 AZ’s is the correct answer.

143
Q

My application can never have a situation where eis is below 6 instances, what is my best option,

  • 2 instances in 3 AZs
  • 3 instances in 2 AZs
  • 1 instance in 6 AZs
  • 1 instance in 7 AZ’s
A

Here you need to focus on again what is the min capacity needed, it is 9 instance but in this case, you need 9 instances s100% of the time and if an AZ was to fail with just 9 instances you would drop below the 9 for a small period and this would not meet the requirement so you have to OVER PROVISION capacity. But we also need to look at the lowest cost too, this would be 1 instance in 7 AZs, this way you only have an extra instance over an above the 100% requires. It would also be important to factor in reservation here so in the event of a single instance or Az failure you are guaranteed to be able to restart the instance.

144
Q

I am using an NLB, can I terminate TLS at the NLB?

A

Yes, you used not be able able to terminate at the NLB, this was added as a feature. Also when you terminate at the NLB the IP is preserved.

145
Q

When using an NLB and terminating TLS, is the IP preserved?

A

Yes, when AWS added the ability to terminate TLS at the NLB, they added the ability to keep the client IP.

146
Q

I am using an NLB and terminating TLS, do I need the proxy protocol to preserve the client IP?

A

No, the NLB will preserve the client IP without the need for proxy protocol.

147
Q

Does the classic load balancer preserve the client IP?

A

No, you can use the proxy protocol to get the client IP when using classic LB. Also, the classic LB is not recommended to be used by AWS any more.

148
Q

How does the proxy protocol work and is it used in the NLB?

A

The proxy protocol is not used with the NLB, it is used with the classic Load balancer. The proxy protocol works by saving the client IP and when the connection is created to the server, the first lines sent to the server is the contains the client IP, it is in ASCII format, looks like this, PROXY TCP4 198.51.100.22 203.0.113.7 35646 80\r\n

149
Q

With NLB can I create it in a single AZ?

A

Yes, just include a single subnet.

150
Q

Can I use WebSockets with the NLB?

A

Yes, NLB is an L4 so not special handlines will take place?

151
Q

Can I use UDP with an NLB?

A

Yes

152
Q

I am using NLB with TLS, how do I use certs?

A

Certs can be created or uploaded to IAM or ACM

153
Q

For NLB is back end auth supported?

A

No, unlike ALB where backend auth is supported.

154
Q

What is a TCP Load Balancer Capacity Unit (LCU)?

A

The LCU metrics for the TCP traffic is as follows:

800 new TCP connections per second.
100,000 active TCP connections (sampled per minute).
1 GB per hour for EC2 instances, containers and IP addresses as targets.

155
Q

I have a load balancer where sticky sessions are used, there is an uneven distribution across my instances, why is this?

A

This is possible because of the sticky session is holding the session to the instance for long periods and over time you may get inbalance across instances.

156
Q

I have a load balancer where sticky sessions are used, there is an uneven distribution across my instances, how cna I fix this?

A

Disable sticky sessions and start using an elastic cache where we session information is not needed by the application on the instance. This way we can now free the LB to distribute the request to any instance.

157
Q

What tracing functionality has the ALB?

A

Request tracing, where the X-Amzn-Trace-Id is automatically added to incoming requests and if access logs are enabled the content of this header is captured.

158
Q

How cna I load balance for UDP?

A

The NLB is a layer4 load balancer and supports UDP

159
Q

Dose the ALB support HTTP/2?

A

Yes

160
Q

I wnat to ensure the ELB can not be deleted, how can I do this?

A

You can enable ELB deletion protection.

161
Q

What do you pay for with the ELB?

A

You pay 0.0225 per ALB per month ($16)

You pay for the Loadbalancer capacity unity (LCU)

162
Q

I am using a VPN connecting to a VPC with an ELB, how can I load balance ot VM on my on-prem?

A

You can use the ELB with IP as a target to send traffic to on-prem through the VPN.

163
Q

How can I set up redirecting customers from HTTP to https?

A

You set up redirects on the routing rules, normally this is forwared but you can also select redirect.

164
Q

I wnat to send a fixed response to the client, how can i do this?

A

You can use fixed responses.

165
Q

I have a set of targets that my ELB is sending traffic to, when I add a new target it takes time for the target to start up the application, this is causing errors as traffic form the ELB is sent before the app is ready to receive it, how cna I fix this?

A

You can use the ELB slow start feature to delay the ELB form sending traffic to the target.

166
Q

We know the ELB supports IPv4 and IPv6, is IPv6 supported on the backend?

A

No, it means HTTP/s arives on the front end for IPv6 but is sent to the backend s IPv4.

167
Q

I wnat to add authentication to my application using OICD, how cna I do this without changing my application, my application is using an ALB?

A

ALB supports authentication using social identities, SAML and an IdP. You cna use OICD

168
Q

I wnat to add authentication to my application using OICD, how cna I do this without changing my application, my application is using an ALB?

A

ALB supports authentication using social identities, SAML and an IdP. You cna use OECD. This is even better in it integrates with Cognito and where Cognito identity provider pool can be used.

169
Q

What is an LCU?

A
  • 25 new connection per second
  • 3K active connections
    2.22mbs (1GB per HR)
    1K rules evaluation
    You are billed for the max of theses