Amazon web services – How to launch EC2 instance via CLI in any availability zone?

Create a VPC:
If you don’t already have a VPC, you’ll need to create one. This is the network environment where your EC2 instances and ELB will reside.

Create Private Subnets:
Create one or more private subnets within your VPC. These subnets should not have a direct route to the internet, which means they should not have a route table with an internet gateway attached.

Launch EC2 Instances:
Launch your EC2 instances in the private subnets. Make sure they are properly configured with your application and any necessary software.

Create a Security Group:
Create a security group for your EC2 instances to control inbound traffic. Ensure that the security group allows traffic from the ELB on the required ports.

Create an Application Load Balancer (ALB):
In the AWS Management Console, go to the EC2 service, and under "Load Balancers," create an Application Load Balancer (ALB). During the setup process, configure it to use the private subnets and create a listener for the application’s protocol and port.

Configure Target Groups:
Create one or more target groups to group your EC2 instances. Associate the target groups with your ALB. The target group defines the health check settings and which instances should receive traffic from the ALB.

Register EC2 Instances:
Register your EC2 instances with the target groups. The ALB will route traffic to these instances based on the rules you define.

Configure Health Checks:
Set up health checks within your target group to ensure that the ALB only directs traffic to healthy instances.

Create Security Groups for the ALB:
Create a security group for the ALB and configure it to allow incoming traffic on the required ports (e.g., 80 for HTTP or 443 for HTTPS) from clients. You can limit the allowed source IP ranges.

Update Route Tables:
Ensure that the route tables for your private subnets include a route to the ALB via the VPC’s local route. This allows the private instances to route their response traffic to the ALB.

Update DNS Records:
Update your DNS records to point to the DNS name of your ALB.

Testing and Monitoring:
Test the setup to ensure that traffic is properly balanced and that instances are healthy. Use CloudWatch and ALB logs to monitor the performance and health of your application.