AWS Classroomnotes 12/Feb/2023

AWS Networking Workshop – Part 1

Enabling DNS Names in VPC

Create a VPC with atleast one public subnet.
Create an ec2 instance in public subnet, ensure the security group rule is open for 22 and 80
By default in vpc the Public DNS Names are not enabled
To enable public DNS names

DHCP Options Set

DHCP Options set is used to set the DNS Servers in VPC

Create an ec2 instance with some predefined private ip.

Create a Network interface in the subnet (zone) where your ec2 instance is running.
Choose Custom for private ip address.
Attach this network interface to your ec2 instance

Lab Prep

Create an ec2 instance and ensure you execute the following steps

sudo apt update
sudo apt install apache2 stress -y
sudo apt install php libapache2-mod-php php-mysql -y
sudo -i 
echo "<?php phpinfo(); ?>" > /var/www/html/info.php

Navigate to http://publicip/info.php
Create an AMI
Wait till the AMI creation is completed
Delete the ec2 instance

Load Balancing

OSI Model of Networking

Layers
Layers & Protocols

Layer 4 and Layer 7 LoadBalancing

Load Balancing can be done at Layer 4 and Layer 7
Layer 4:
- Aware: IP, Port, TCP/UDP, MAC
Layer 7:
- Aware: IP, Port, TCP/UDP, MAC, HTTP, SSL/TLS (security)

Load Balancers in AWS

In AWS we have following load balancers
- AWS classic Load Balancer:
  - Both L4 and L7 loadbalancing
- AWS Network Load Balancer:
  - Works on Layer 4
- AWS Application Load Balancer
  - Works on Layer 7

Layer 4 load balancing

Create a VPC with two subnets in two different zones
Create an ec2 instance in subnet 1 and subnet2
Ensure 80 and 22 ports are opened in securty group for all.
Create a Layer 4 load balancer using Network Load Balancer
Now access by using `http:///info.php

Layer 7 loadbalancing

AWS has Application Load Balancer which can perform layer 7 load balancing
login into web1 and execute the following

# web1
# root
mkdir -p /var/www/html/images
echo "<h1>images</h1>" > /var/www/html/images/index.html

access the application by using http://publicip/images/index.html
login into web2 and execute the following

# web2
# root
mkdir -p /var/www/html/music
echo "<h1>music</h1>" > /var/www/html/music/index.html

access the application by using http://publicip/music/index.html
http health checks:
- Status Codes
- Interval: how frequently load balancer will perform health checks?
- Healthy threshold: How many consecutive health checks should be passed to consider the instance healthy
- UnHeathy threshold: How many consecutive health checks should be failed to consider the instance unhealthy
Target Group for every application component running independently i.e. we will be creating two target groups images and music
Lets create a Application Load Balancer
Select the default target group for now
Complete the creation
Path Based Routing: Refer Here
Now lets manage rules in listener