13. Application Load Balancer (ALB)

Creating an Application Load Balancer (ALB) and configuring it with multiple target groups can significantly enhance your application's scalability and reliability. Here's a step-by-step guide along with a diagram:

Steps:

1. Instance Setup:

   • Launch four EC2 instances with private subnets, placing two instances in subnet 1A and the remaining two in subnets 1B and 1C.

   • Ensure proper userdata configuration for each instance.

2. Target Group Creation:

   • Create three target groups:

     • Home Page: HTTP 80, health check /homepage/, add all instances.

     • Movies: HTTP 80, health check /movies/, add movies server only.

     • Shows: HTTP 80, health check /shows/, add shows server only.

3. Load Balancer Configuration:

   • Create an ALB (Internet-facing) in your VPC, selecting the public subnets and appropriate security group.

   • Configure two listeners: HTTP (80) and HTTPS (443).

   • Select the SSL certificate for your domain (e.g., www.cloudvishwakarma.in).

4. Route 53 Setup:

   • Create a Route 53 record pointing to the ALB.

5. HTTP to HTTPS Redirection:

   • Configure HTTP to HTTPS redirection:

     • Create a rule to redirect HTTP (80) traffic to HTTPS (443).

     • Ensure proper HTTPS redirection for all incoming traffic.

6. Path-Based Routing:

   • Implement path-based routing for different content:

     • Create rules to direct traffic based on paths (e.g., /movies/*, /shows/*).

     • Ensure each rule forwards traffic to the corresponding target group.

7. Error Handling:

   • Set up error handling rules:

     • Define rules for specific paths (e.g., /google/*) and provide appropriate responses (e.g., 503 error with a message).

8. Virtual Hosting:

   • Optionally, configure virtual hosting for multiple hosts:

     • Utilize host headers to direct traffic to different backend services based on the requested host.

Diagram:

                  +---------+
                  |  ALB    |
                  |         |
                  +----+----+
                       |
          +------------+------------+
          |                         |
    +-----v-----+             +-----v-----+
    | Target    |             | Target    |
    | Group:    |             | Group:    |
    | Homepage  |             | Movies    |
    |           |             |           |
    +-----+-----+             +-----+-----+
          |                         |
          |                         |
    +-----v-----+             +-----v-----+
    | Target    |             | Target    |
    | Group:    |             | Group:    |
    | Shows     |             | ...       |
    |           |             |           |
    +-----------+             +-----------+

By following these steps and configuring your ALB accordingly, you can efficiently distribute incoming traffic across your EC2 instances and provide a seamless experience for your users.