# Creating Amazon ECS resources using AWS CLI commands for CloudFormation
<a name="ecs-cloudformation-cli"></a>

Another way to use Amazon ECS with CloudFormation is through the AWS CLI. You can use commands to create your CloudFormation stacks for Amazon ECS components like task definitions, clusters, and services and deploy them. The following tutorial shows how you can use the AWS CLI to create Amazon ECS resources using an CloudFormation template.

## Prerequisites
<a name="ecs-cloudformation-cli-prerequisite"></a>
+ The steps in [Set up to use Amazon ECS](get-set-up-for-amazon-ecs.md) have been completed.
+ Your IAM user has the required permissions specified in the [AmazonECS\$1FullAccess](security-iam-awsmanpol.md#security-iam-awsmanpol-AmazonECS_FullAccess) IAM policy example.

## Step 1: Create a stack
<a name="ecs-cloudformation-cli-create"></a>

To create a stack using the AWS CLI saved in a file called `ecs-tutorial-template.yaml`, run the following command.

```
cat << 'EOF' > ecs-tutorial-template.yaml
AWSTemplateFormatVersion: '2010-09-09'
Description: '[AWSDocs] ECS: load-balanced-web-application'
Parameters:
  VpcCidr:
    Type: String
    Default: '10.0.0.0/16'
    Description: CIDR block for the VPC
  ContainerImage:
    Type: String
    Default: 'public.ecr.aws/ecs-sample-image/amazon-ecs-sample:latest'
    Description: Container image to use in task definition

  PublicSubnet1Cidr:
    Type: String
    Default: '10.0.1.0/24'
    Description: CIDR block for public subnet 1
  
  PublicSubnet2Cidr:
    Type: String
    Default: '10.0.2.0/24'
    Description: CIDR block for public subnet 2
  
  PrivateSubnet1Cidr:
    Type: String
    Default: '10.0.3.0/24'
    Description: CIDR block for private subnet 1
  
  PrivateSubnet2Cidr:
    Type: String
    Default: '10.0.4.0/24'
    Description: CIDR block for private subnet 2
  
  ServiceName:
    Type: String
    Default: 'tutorial-app'
    Description: Name of the ECS service
  
  ContainerPort:
    Type: Number
    Default: 80
    Description: Port on which the container listens
  
  DesiredCount:
    Type: Number
    Default: 2
    Description: Desired number of tasks
  
  MinCapacity:
    Type: Number
    Default: 1
    Description: Minimum number of tasks for auto scaling
  
  MaxCapacity:
    Type: Number
    Default: 10
    Description: Maximum number of tasks for auto scaling

Resources:
  # VPC and Networking
  VPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: !Ref VpcCidr
      EnableDnsHostnames: true
      EnableDnsSupport: true
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-vpc'

  # Internet Gateway
  InternetGateway:
    Type: AWS::EC2::InternetGateway
    Properties:
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-igw'

  InternetGatewayAttachment:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      InternetGatewayId: !Ref InternetGateway
      VpcId: !Ref VPC

  # Public Subnets for ALB
  PublicSubnet1:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Select [0, !GetAZs '']
      CidrBlock: !Ref PublicSubnet1Cidr
      MapPublicIpOnLaunch: true
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-public-subnet-1'

  PublicSubnet2:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Select [1, !GetAZs '']
      CidrBlock: !Ref PublicSubnet2Cidr
      MapPublicIpOnLaunch: true
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-public-subnet-2'

  # Private Subnets for ECS Tasks
  PrivateSubnet1:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Select [0, !GetAZs '']
      CidrBlock: !Ref PrivateSubnet1Cidr
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-private-subnet-1'

  PrivateSubnet2:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Select [1, !GetAZs '']
      CidrBlock: !Ref PrivateSubnet2Cidr
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-private-subnet-2'

  # NAT Gateways for private subnet internet access
  NatGateway1EIP:
    Type: AWS::EC2::EIP
    DependsOn: InternetGatewayAttachment
    Properties:
      Domain: vpc
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-nat-eip-1'

  NatGateway2EIP:
    Type: AWS::EC2::EIP
    DependsOn: InternetGatewayAttachment
    Properties:
      Domain: vpc
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-nat-eip-2'

  NatGateway1:
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId: !GetAtt NatGateway1EIP.AllocationId
      SubnetId: !Ref PublicSubnet1
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-nat-1'

  NatGateway2:
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId: !GetAtt NatGateway2EIP.AllocationId
      SubnetId: !Ref PublicSubnet2
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-nat-2'

  # Route Tables
  PublicRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-public-routes'

  DefaultPublicRoute:
    Type: AWS::EC2::Route
    DependsOn: InternetGatewayAttachment
    Properties:
      RouteTableId: !Ref PublicRouteTable
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref InternetGateway

  PublicSubnet1RouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref PublicRouteTable
      SubnetId: !Ref PublicSubnet1

  PublicSubnet2RouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref PublicRouteTable
      SubnetId: !Ref PublicSubnet2

  PrivateRouteTable1:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-private-routes-1'

  DefaultPrivateRoute1:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref PrivateRouteTable1
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway1

  PrivateSubnet1RouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref PrivateRouteTable1
      SubnetId: !Ref PrivateSubnet1

  PrivateRouteTable2:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-private-routes-2'

  DefaultPrivateRoute2:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref PrivateRouteTable2
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway2

  PrivateSubnet2RouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref PrivateRouteTable2
      SubnetId: !Ref PrivateSubnet2

  # Security Groups
  ALBSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: !Sub '${AWS::StackName}-alb-sg'
      GroupDescription: Security group for Application Load Balancer
      VpcId: !Ref VPC
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: 80
          ToPort: 80
          CidrIp: 0.0.0.0/0
          Description: Allow HTTP traffic from internet
      SecurityGroupEgress:
        - IpProtocol: -1
          CidrIp: 0.0.0.0/0
          Description: Allow all outbound traffic
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-alb-sg'

  ECSSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: !Sub '${AWS::StackName}-ecs-sg'
      GroupDescription: Security group for ECS tasks
      VpcId: !Ref VPC
      SecurityGroupIngress:
        - IpProtocol: tcp
          FromPort: !Ref ContainerPort
          ToPort: !Ref ContainerPort
          SourceSecurityGroupId: !Ref ALBSecurityGroup
          Description: Allow traffic from ALB
      SecurityGroupEgress:
        - IpProtocol: -1
          CidrIp: 0.0.0.0/0
          Description: Allow all outbound traffic
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-ecs-sg'

  # Application Load Balancer
  ApplicationLoadBalancer:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Name: !Sub '${AWS::StackName}-alb'
      Scheme: internet-facing
      Type: application
      Subnets:
        - !Ref PublicSubnet1
        - !Ref PublicSubnet2
      SecurityGroups:
        - !Ref ALBSecurityGroup
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-alb'

  ALBTargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      Name: !Sub '${AWS::StackName}-tg'
      Port: !Ref ContainerPort
      Protocol: HTTP
      VpcId: !Ref VPC
      TargetType: ip
      HealthCheckIntervalSeconds: 30
      HealthCheckPath: /
      HealthCheckProtocol: HTTP
      HealthCheckTimeoutSeconds: 5
      HealthyThresholdCount: 2
      UnhealthyThresholdCount: 5
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-tg'

  ALBListener:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      DefaultActions:
        - Type: forward
          TargetGroupArn: !Ref ALBTargetGroup
      LoadBalancerArn: !Ref ApplicationLoadBalancer
      Port: 80
      Protocol: HTTP

  # ECS Cluster
  ECSCluster:
    Type: AWS::ECS::Cluster
    Properties:
      ClusterName: !Sub '${AWS::StackName}-cluster'
      CapacityProviders:
        - FARGATE
        - FARGATE_SPOT
      DefaultCapacityProviderStrategy:
        - CapacityProvider: FARGATE
          Weight: 1
        - CapacityProvider: FARGATE_SPOT
          Weight: 4
      ClusterSettings:
        - Name: containerInsights
          Value: enabled
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-cluster'

  # IAM Roles
  ECSTaskExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub '${AWS::StackName}-task-execution-role'
      AssumeRolePolicyDocument:
        Version: '2012-10-17		 	 	 '
        Statement:
          - Effect: Allow
            Principal:
              Service: ecs-tasks.amazonaws.com
            Action: sts:AssumeRole
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AmazonECSTaskExecutionRolePolicy
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-task-execution-role'

  ECSTaskRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub '${AWS::StackName}-task-role'
      AssumeRolePolicyDocument:
        Version: '2012-10-17		 	 	 '
        Statement:
          - Effect: Allow
            Principal:
              Service: ecs-tasks.amazonaws.com
            Action: sts:AssumeRole
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-task-role'

  # CloudWatch Log Group
  LogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Sub '/ecs/${AWS::StackName}'
      RetentionInDays: 7

  # ECS Task Definition
  TaskDefinition:
    Type: AWS::ECS::TaskDefinition
    Properties:
      Family: !Sub '${AWS::StackName}-task'
      Cpu: '256'
      Memory: '512'
      NetworkMode: awsvpc
      RequiresCompatibilities:
        - FARGATE
      ExecutionRoleArn: !GetAtt ECSTaskExecutionRole.Arn
      TaskRoleArn: !GetAtt ECSTaskRole.Arn
      ContainerDefinitions:
        - Name: !Ref ServiceName
          Image: !Ref ContainerImage
          PortMappings:
            - ContainerPort: !Ref ContainerPort
              Protocol: tcp
          Essential: true
          LogConfiguration:
            LogDriver: awslogs
            Options:
              awslogs-group: !Ref LogGroup
              awslogs-region: !Ref AWS::Region
              awslogs-stream-prefix: ecs
          HealthCheck:
            Command:
              - CMD-SHELL
              - curl -f http://localhost/ || exit 1
            Interval: 30
            Timeout: 5
            Retries: 3
            StartPeriod: 60
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-task'

  # ECS Service
  ECSService:
    Type: AWS::ECS::Service
    DependsOn: ALBListener
    Properties:
      ServiceName: !Sub '${AWS::StackName}-service'
      Cluster: !Ref ECSCluster
      TaskDefinition: !Ref TaskDefinition
      DesiredCount: !Ref DesiredCount
      LaunchType: FARGATE
      PlatformVersion: LATEST
      NetworkConfiguration:
        AwsvpcConfiguration:
          AssignPublicIp: DISABLED 
          SecurityGroups:
            - !Ref ECSSecurityGroup
          Subnets:
            - !Ref PrivateSubnet1
            - !Ref PrivateSubnet2
      LoadBalancers:
        - ContainerName: !Ref ServiceName
          ContainerPort: !Ref ContainerPort
          TargetGroupArn: !Ref ALBTargetGroup
      DeploymentConfiguration:
        MaximumPercent: 200
        MinimumHealthyPercent: 50
        DeploymentCircuitBreaker:
          Enable: true
          Rollback: true
      EnableExecuteCommand: true  # For debugging
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-service'

  # Auto Scaling Target
  ServiceScalingTarget:
    Type: AWS::ApplicationAutoScaling::ScalableTarget
    Properties:
      MaxCapacity: !Ref MaxCapacity
      MinCapacity: !Ref MinCapacity
      ResourceId: !Sub 'service/${ECSCluster}/${ECSService.Name}'
      RoleARN: !Sub 'arn:aws:iam::${AWS::AccountId}:role/aws-service-role/ecs.application-autoscaling.amazonaws.com/AWSServiceRoleForApplicationAutoScaling_ECSService'
      ScalableDimension: ecs:service:DesiredCount
      ServiceNamespace: ecs

  # Auto Scaling Policy - CPU Utilization
  ServiceScalingPolicy:
    Type: AWS::ApplicationAutoScaling::ScalingPolicy
    Properties:
      PolicyName: !Sub '${AWS::StackName}-cpu-scaling-policy'
      PolicyType: TargetTrackingScaling
      ScalingTargetId: !Ref ServiceScalingTarget
      TargetTrackingScalingPolicyConfiguration:
        PredefinedMetricSpecification:
          PredefinedMetricType: ECSServiceAverageCPUUtilization
        TargetValue: 70.0
        ScaleOutCooldown: 300
        ScaleInCooldown: 300

Outputs:
  VPCId:
    Description: VPC ID
    Value: !Ref VPC
    Export:
      Name: !Sub '${AWS::StackName}-VPC-ID'

  LoadBalancerURL:
    Description: URL of the Application Load Balancer
    Value: !Sub 'http://${ApplicationLoadBalancer.DNSName}'
    Export:
      Name: !Sub '${AWS::StackName}-ALB-URL'

  ECSClusterName:
    Description: Name of the ECS Cluster
    Value: !Ref ECSCluster
    Export:
      Name: !Sub '${AWS::StackName}-ECS-Cluster'

  ECSServiceName:
    Description: Name of the ECS Service
    Value: !GetAtt ECSService.Name
    Export:
      Name: !Sub '${AWS::StackName}-ECS-Service'

  PrivateSubnet1:
    Description: Private Subnet 1 ID
    Value: !Ref PrivateSubnet1
    Export:
      Name: !Sub '${AWS::StackName}-Private-Subnet-1'

  PrivateSubnet2:
    Description: Private Subnet 2 ID
    Value: !Ref PrivateSubnet2
    Export:
      Name: !Sub '${AWS::StackName}-Private-Subnet-2'
EOF
```

 The template used in this tutorial creates an Amazon ECS service with two tasks that run on Fargate. The tasks each run a sample Amazon ECS application. The template also creates an Application Load Balancer that distributes application traffic and an Application Auto Scaling policy that scales the application based on CPU utilization. The template also creates the networking resources necessary to deploy the application, the logging resources for container logs, and an Amazon ECS task execution IAM role. For more information about the task execution role, see [Amazon ECS task execution IAM role](task_execution_IAM_role.md). For more information about auto scaling, see [Automatically scale your Amazon ECS service](service-auto-scaling.md).

After creating a template file, use the following command to create a stack. The `--capabilities` flag is required to create an Amazon ECS task execution role as specified in the template. You can also specify the `--parameters` flag to customize the template parameters.

```
aws cloudformation create-stack \
      --stack-name ecs-tutorial-stack \
      --template-body file://ecs-tutorial-template.yaml \
      --region aws-region \
      --capabilities CAPABILITY_NAMED_IAM
```

After running the `create-stack` command, you can use `describe-stacks` to check the status of stack creation.

```
aws cloudformation describe-stacks \
      --stack-name ecs-tutorial-stack \
      --region aws-region
```

## Step 2: Verify Amazon ECS resource creation
<a name="ecs-cloudformation-cli-verify"></a>

To ensure that Amazon ECS resources are created correctly, follow these steps.

1. Run the following command to list all task definitions in an AWS Region.

   ```
   aws ecs list-task-definitions
   ```

   The command returns a list of task definition Amazon Resource Name (ARN)s. The ARN of the task definition that you created using the template will be displayed in the following format.

   ```
   {
       "taskDefinitionArns": [
        .....
           "arn:aws:ecs:aws-region:111122223333:task-definition/ecs-tutorial-stack-task:1",
        .....   
       ]
   }
   ```

1. Run the following command to list all clusters in an AWS Region.

   ```
   aws ecs list-clusters
   ```

   The command returns a list of cluster ARNs. The ARN of the cluster that you created using the template will be displayed in the following format.

   ```
   {
       "clusterArns": [
           .....
           "arn:aws:ecs:aws-region:111122223333:cluster/ecs-tutorial-stack-cluster",
           .....
       ]
   }
   ```

1. Run the following command to list all services in the cluster `ecs-tutorial-stack-cluster`.

   ```
   aws ecs list-services \
         --cluster ecs-tutorial-stack-cluster
   ```

   The command returns a list of service ARNs. The ARN of the service that you created using the template will be displayed in the following format.

   ```
   {
       "serviceArns": [
           "arn:aws:ecs:aws-region:111122223333:service/ecs-tutorial-stack-cluster/ecs-tutorial-stack-service"
       ]
   }
   ```

You can also obtain the DNS name of the Application Load Balancer that was created and use it to verify the creation of resources. To obtain the DNS name, run the following command:

 Run the following command to retrieve outputs of the created stack. 

```
aws cloudformation describe-stacks \
  --stack-name ecs-tutorial-stack \
  --region aws-region \
  --query 'Stacks[0].Outputs[?OutputKey==`LoadBalancerURL`].OutputValue' \
  --output  text
```

Output:

```
http://ecs-tutorial-stack-alb-0123456789.aws-region.elb.amazonaws.com
```

Paste the DNS name into a browser to view a webpage that displays a sample Amazon ECS application.

## Step 3: Clean up
<a name="ecs-cloudformation-cli-cleanup"></a>

To clean up the resources you created, run the following command.

```
aws cloudformation delete-stack \
      --stack-name ecs-stack
```

The `delete-stack` command initiates deletion of the CloudFormation stack that was created in this tutorial, deleting all the resources in the stack. To verify deletion, you can repeat the procedure in [Step 2: Verify Amazon ECS resource creation](#ecs-cloudformation-cli-verify). The list of ARNs in the outputs will no longer include a task definition called `ecs-tutorial-stack-task` or a cluster called `ecs-tutorial-stack-cluster`. The `list-services` call will fail.