Provisioning ECS via EC2 infrastructure using Terraform

Execution Steps to create infrastructure

1. clone
2. cd terraform-learning-example
3. Create an EC2 Key Pair (Optional)
4. Add your container image url in "container-definitions.json" file.
5. terraform init
6. terraform plan
7. terraform apply

Execution Steps to delete infrastructure

1. Scale down EC2 auto scaling group
2. Terminate EC2 instances
3. Run terraform destroy

Details

alb.tf - also known as "Application Load Balancer". This is a load balancer configured for EC2 instances. It consists of 3 main parts:

1. aws_lb - main load balancer configuration.
2. aws_lb_target_group - load balancer security target group using region VPC as subnets.
3. aws_lb_listener - the route request enabled to be recieved by load balancer.

ami.tf - also known as "Amazon Machine Images". This is an image configuration for running EC2 instances via launch configuration on autoscaling group.
asg.tf - also known as "Autoscaling Group". This enables scale out configuration of EC2 instances and requires the load balancer arn.
Details:

1. aws_launch_configuration - resource configuration to launch auto scale for EC2 instances via Load Balancer.
2. aws_autoscaling_group - main configuration for auto scaling EC2 instances.

ecs.tf - also known as "Elastic Container Service". A service holding out container instances.
Details:

1. aws_ecs_capacity_provider - provides scaling of ECS instances.
2. aws_ecs_cluster - main resource that holds ECS tasks and instances.
3. aws_ecs_cluster_capacity_providers - defines the capacity provider used in the cluster.
4. aws_ecs_task_definition - configurations for the containers.
5. aws_ecs_service - main resource to run ECS instances.
6. aws_cloudwatch_log_group - cloudwatch resource attached to our ecs instances for log tracing.

iam.tf - also known as "Identity and Access Management". This provides role accesses for certain resources.
main.tf - declare providers.
outputs.tf - get outputs from resources and print it once you run the terraform command.
security-group.tf - declare security groups that is required by other resources.
variables.tf - setup for input items that can be provided inside terraform execution.
vpc.tf - also known as "Virtual Private Cloud". Using a terraform vpc module, creation of private network with high availability can be achieved and be used by other resources that requires it.