AWS CloudFormation service was unable to place a task because no container instance met all of its requirements

Question

I am trying to create an ECS using a ci/cd pipeline. I have defined TaskDefination and ECSService along with VPC.

The cloudformation created the cluster and got stuck ECSService creation.

I went to the ECSService event, I found the error 'service my-service-name was unable to place a task because no container instance met all of its requirements. Reason: No Container Instances were found in your cluster. For more information, see the Troubleshooting section.'

Am I missing someting in my pipeline?

Here is my TaskDefination and ECSService

AWSTemplateFormatVersion: 2010-09-09
Description: The CloudFormation template for the Fargate ECS Cluster.

Parameters:
  Stage:
    Type: String
  ContainerPort:
    Type: Number
  ImageURI:
    Type: String

Resources:

  # Create an ECS Cluster
  Cluster:
    Type: AWS::ECS::Cluster
    Properties:
      ClusterName: !Join ['-', [!Ref Stage, !Ref 'AWS::AccountId', 'Cluster']]

  # Create a VPC
  VPC:
    Type: AWS::EC2::VPC
    Properties: 
      CidrBlock: 10.0.0.0/16
      EnableDnsHostnames: True
      EnableDnsSupport: True

  # Create a Subnet
  SubnetA:
    Type: AWS::EC2::Subnet
    Properties:
      CidrBlock: 10.0.0.0/24
      VpcId: !Ref VPC
      AvailabilityZone: !Join ['', [!Ref "AWS::Region", 'a']]

  # Create a Subnet
  SubnetB:
    Type: AWS::EC2::Subnet
    Properties:
      CidrBlock: 10.0.1.0/24
      VpcId: !Ref VPC
      AvailabilityZone: !Join ['', [!Ref "AWS::Region", 'b']]

  # Create Access Role for ECS-Tasks
  ExecutionRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Join ['-', [!Ref Stage, !Ref 'AWS::AccountId', 'ExecutionRole']]
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Principal:
              Service: ecs-tasks.amazonaws.com
            Action: 'sts:AssumeRole'
      ManagedPolicyArns:
        - 'arn:aws:iam::aws:policy/service-role/AmazonECSTaskExecutionRolePolicy'

  # Create a TaskDefinition with container details
  TaskDefinition:
    Type: AWS::ECS::TaskDefinition
    Properties:
      NetworkMode: awsvpc
      RequiresCompatibilities:
        - 'EC2'
      TaskRoleArn: !Ref ExecutionRole
      ExecutionRoleArn: !Ref ExecutionRole
      ContainerDefinitions:
        - Name: !Join ['-', [!Ref Stage, !Ref 'AWS::AccountId', 'Container']]
          Image: !Ref ImageURI
          Cpu: 1024
          Memory: 1024
          PortMappings:
            - ContainerPort: !Ref ContainerPort
              HostPort: !Ref ContainerPort

  # Create an ECS Service and add created Cluster, TaskDefintion, Subnets, TargetGroup and SecurityGroup
  ECSService:
    Type: AWS::ECS::Service
    Properties:
      ServiceName: !Join ['-', [!Ref Stage, !Ref 'AWS::AccountId', 'ECSService']]
      Cluster: !Ref Cluster
      TaskDefinition: !Ref TaskDefinition
      DesiredCount: 1
      LaunchType: EC2
      NetworkConfiguration: 
        AwsvpcConfiguration:
          Subnets:
            - !Ref SubnetA
            - !Ref SubnetB

I have tried answers of already posted questions. In most of cases people get this error on AWS web interface. For me ECS is working using Web interface. I am not able to get it working using my pipeline.

Answer 1

You have to explicitly provision EC2 container instances for your ECS tasks. Your current TF code does not create any EC2 instances for used by your ECS cluster and tasks.