Elastic Load Balancing

• Elastic Load Balancing automatically distributes your incoming traffic across multiple targets
• Such as EC2 instances, containers, and IP addresses, in one or more Availability Zones.
• EC2 > Load Balancing

Types of load balancers

• Application Load Balancers
• Network Load Balancers
• Gateway Load Balancers
• Classic Load Balancers (Deprecated)

Target Groups

• EC2 > Load Balancing > Target groups > Create target group
  • Choose a target type > Instances
  • Available instances > Select instance > include as pending below

Application Load Balancers

• Load Balancer type: Layer 7
• Protocol listeners: HTTP, HTTPS, gRPC
• EC2 > Load balancers > Create Application Load Balancer
  • Scheme > Internet-facing
  • Listeners and routing > add target group
    • Protol: HTTP
• Select load balancer > Listeners > View/edit rules
  • Add rules > Insert Rules
• Can be filtered(load-balance) based on
  • sub-domain
  • path
  • query string …

NOTE

• IP
  • IPv4 settings –> Assigned by AWS
• Target-group
  • Create it using HTTPs

Sticky sessions for your Application Load Balancer

• By default, an Application Load Balancer routes each request independently to a registered target based on the chosen load-balancing algorithm.
• The sticky session feature enable the load balancer to bind a user's session to a specific target
• Application Load Balancers support both
  • Duration-based cookies and
    • AWSALB is the only name used across all target groups.
  • Application-based cookies
    • Here cookie names have to be specified individually for each target group

Network Load Balancers

• Load Balancer type: Layer 4
• Protocol listeners: TCP, UDP, TLS
• EC2 > Load balancers > Create Network Load Balancer
  • Scheme > Internet-facing
  • Listeners and routing > add target group
    • Protol: TCP

NOTE

• IP
  • IPv4 settings –> Assigned by AWS or Assign Elastic IP
• Target-group
  • Create it using TCP

Amazon EC2 Auto Scaling

• It helps you ensure that you have the correct number of Amazon EC2 instances available to handle the load for your application.
• It launch or terminate instances as demand on your application increases or decreases.
• Scale in and Scale out
• Types
  • Vertical Scaling
    • Increase Compute power of current instance
  • Horizontal Scaling
    • Launch some paraller instances
    • By default profided by AWS
• EC2 > Auto Scaling > Auto Scaling Groups > Create
  • Launch template
  • Attach/Create Load balancer