Advanced Networking

Question 1

ELB

Answer 1

Load balancing is a common method used for distributing incoming traffic among servers.
highly available and fault tolerant architecture.

Question 2

important facts

Answer 2

when used within a VPC, ELB can act as an internal load balancer and load balance to internal EC2 instances on private subnets.
automatically stop serving traffic to an unhealthy instance.
help reduce compute power on an EC2 instance by allowing for an SSL certificate to be applied directly to the elastic load balancer.

Question 3

Auto Scaling

Answer 3

automates the process of increasing or decreasing the number of provisioned on-demand instances available for your application.

Question 4

auto scaling components

Answer 4

Lauch configuration;

auto scaling group

Question 5

Launch Configuration

Answer 5

EC2 template used when the auto scaling group needs to provision an additional instance.

Question 6

Auto scaling group

Answer 6

all the rules and settings that govern if/when an EC2 instance is automatically provisioned to terminated.

• • Number of MIN and MAX allows instances
• • VPC &AZa to launch instances into
• • if provisioned instances should receive traffic from a ELB
• • Scaling policies
• • SNS notifications.

Question 7

Classic vs Application ELB

Answer 7

classic is designed for simple balancing of traffic to multiple EC2 instances.

Question 8

Classic ELB

Answer 8

classic is designed for simple balancing of traffic to multiple EC2 instances.

• • no granular routing “rules”
• • best when all instances contain the same data.

Question 9

APPLICATION ELB

Answer 9

FOR COMPLEX
– CONTENT-BASED RULES Host based rules (based on the host field of the HTTP header) and path based rule(URL path of the HTTP header).
Support ECS Containers, HTTPS, HTTP/2, WebSockets, Access Logs, Sticky Sessions, and AWS WAF(web application firewall).

Question 10

if your application is continually crashing due to high demand, you should make sure the Elastic Load Balancer has the proper scaling polices for adding new instances when needed.

Answer 10

False. It is auto scaling group that contains scaling policies(which dictate the cloudwatch thresholds for adding/removing instances).

Question 11

What is the proper solution you should enact to prevent your application from crashing due to a sudden increase in demand?

Answer 11

Auto Scaling is what provides your architecture with the ability to automate the process of adding more instances to avoid crashes (if the case of sudden increase in demand). Scaling policies are PART of Auto Scaling but are not the overall solution.

Question 12

Target Groups

Answer 12

are where we assign different sets of EC2 instances to receive traffic in an Application Load Balancer. Launch configurations and Auto Scaling groups can be used with either load balancing type, and CloudWatch events are not used in the Application Load Balancer configuration.

Question 13

What best describes the purpose of an Elastic Load Balancer?

Answer 13

To evenly distribute traffic among multiple EC2 instances in separate Availability Zones.

Question 14

Bastion Host

Answer 14

an EC2 instance that lives in a public subnet and is used as a "gateway" for traffic that is destined for instances that live in private subnets.
"critical strong point" of the network - as all traffic must pass through it first.
tight security(usually with extra 3rd party security and monitoring software installed).
access point to "ssh" into an internal network without a VPN.

Question 15

NAT Gateway

Answer 15

• -is designed to provide EC2 instances that live in a private subnet with a route to the internet.
• -prevent any hosts located outside of the VPC from initiating a connection with instances that are associated with it.
• • will only allow incoming traffic through if a request for it originated from an instance in a private subnet.
• • is need for private subnets communicate with the open internet.
• • placing instances in a private subnet creates a higher level of security but also creates the limitation of the instances not being able to download software and software updates.
• must be created in a public Subnet
• be part of the private subnets route table.

Question 16

NAT Instance:

Answer 16

• is identical to a NAT gateway in its purpose.
• it is executed differently by configuring an actual EC2 instance to do the same job.
• is starting to become more of legacy feature in AWS.

Question 17

Bastion Host vs NAT Gateway

Answer 17

A bastion host is used is used as a “gateway” for traffic that is destined for instances located in a private subnet, whereas a NAT gateway provides instances in a private subnet with a route to the internet. A NAT does provide protection for instances in a private subnet, but its primary goal is to allow instances in the private subnet a route to the internet (to download software packages).