Deployment of SpringBoot Services on AWS Elastic Container Services: Part 4 Configure Application Load Balancer Target Groups and Application Load Balancer Listener

For the third part of this thread, please click on Part 3

The Application Load Balancer (ALB) lets your service accept incoming traffic. The ALB automatically routes 

traffic to container instances running on your cluster using them as a target group.

Check your VPC Name: If this is not your first time using this AWS account, you may have multiple VPCs. 

It is important to configure your Target Group with the correct VPC.

• Navigate to the Load Balancer section of the EC2 Console.
• Locate the appropriate load balancer.
  
  
• Select the checkbox next to the appropriate load balancer to see the Load Balancer details.
• In the Description tab, locate the VPC attribute (in this format: vpc-xxxxxxxxxxxxxxxxx).Configure the ALB 
• Target Group

A target group tells a load balancer where to direct traffic to : EC2 instances, fixed IP addresses; or AWS Lambda functions, amongst others. When creating a load balancer, you create one or more listeners and configure listener rules to direct the traffic to one target group.

• Navigate to the Target Group section of the EC2 Console.
• Select Create target group.
• Configure the following Target Group parameters (for the parameters not listed below,
•  keep the default values):
  
  • For the Target group name, enter api.
    
  • For the Protocol, select HTTP.
    
  • For the Port, enter 80.
    
  • For the VPC, select the value that matches the one from the Load Balancer description. 
  • This is most likely NOT your default VPC.
    
  • Access the Advanced health check settings and edit the following parameters as needed: 
    • For Healthy threshold, enter 2.
    • For Unhealthy threshold, enter 2.
    • For Timeout, enter 5.
    • For Interval, enter 6.
• Select Create.

The ALB listener checks for incoming connection requests to your ALB.

Add a Listener to the ALB

• Navigate to the Load Balancer section of the EC2 Console.
• Select the checkbox next to the appropriate load balancer to see the Load Balancer details.
• Select the Listeners tab.

• Select Add listener and edit the following parameters as needed:
  
• For Protocol:port, select HTTP and enter 80.
• For Default action(s), select Forward to and in the Target group field, enter api.
• Select Save.