Deploying Blue/Green and Service Scaling with Backend

Creating ECS Service

Now, we need to create an ECS service to run our containers.

• Search for the keyword ECS in the AWS Console.
• Select the Cluster that you’ve created.
• Scroll down to the Service section and choose Create.

We’ll configure FARGATE for easier usage.

• Choose Launch type as FARGATE.
• Version select LATEST.

• Choose type as Service.
• Family select the Task definition created for the backend and choose the latest version.
• Enter name: backend

• Choose type as Replica and select 1 task to launch.
• Select deployment type as Blue/Green.
• Select deployment configuration as CodeDeployDefault.ECSCanary10Percent5Minutes.
• In the Role section, choose the role created in the preparation step: CodeDeployServiceRole.

Service Discovery

This part is important. For the Frontend Service and Backend Service to communicate, we need to configure Service discovery for the Backend Service with the namespace and service created in Cloud Map (configured with Terraform).

• Select Use service discovery.
• Choose Select an existing namespace and select the namespace fcjresbar.internal that was created previously.
• Choose Select an existing service discovery service and select the backend service.
• Leave other configurations as default.

Networking

Now, we’ll assign this Service and its containers to the network and subnet that we previously created using Terraform.

• VPC: Choose the VPC that we created earlier.
• Subnet: Choose the private subnet (DoAn-network-subnet-private4) created in the preparation step.
• Security group: Select DoAn-network-sg-private.
• Public IP: This option will be disabled to enhance security as traffic is already routed through the Load Balancer.

Load Balancing

Configure some information for the Load Balancer as follows:

• Load balancing type: Choose Application Load Balancer.
• Container: backend 5000:5000 (this port is for both the host and the container).
• Choose Use an existing load balancer.
• Select Doan-alb load balancer.
• Health Check: Keep it as default.

In the Listener section, we’ll create 2 new Listeners.

• Production listener: port 5000, protocol HTTP.
• Test listener: port 8080, protocol HTTP.

The target group section can be kept as default or configured as desired.

Service Auto Scaling

Now, we’ll configure scaling for the container.

• Minimum: 1
• Maximum: 2
• Scaling policy type: Target tracking

Configure the scaling policy:

• Name: ScaleAtThreshold75Percent
• ECS service metric: ECSServiceAverageCPUUtilization
• Target value: 75
• Scale-out cooldown period: 120
• Scale-in cooldown period: 120
• Then click Create to finish.

We need to wait about 5 minutes for the Service to be fully created.