fargate错误:无法从专用子网中提取ECR中承载的容器

我试图创建一个如下的体系结构:一个拥有两个子网的VPC(一个子网是公共的,包含一个natgateway和一个internetgateway,另一个子网是私有的)。

我在一个私有子网中启动了一个fargate服务,它失败并出现以下错误:

CanNotPullContainerError:API错误(500):获取 https://XYZ.dkr.ecr.us-east-1.amazonaws.com/v2/ :NET/HTTP: 等待连接时请求被取消(超过了client.timeout 等待邮件头时)

这是我的CloudInformation模板(服务被故意注释掉,ECR图像URL被置乱):

Resources:
#Network resources: VPC 
  WorkflowVpc:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: "10.0.0.0/16"
      EnableDnsSupport: false
      Tags:
        - Key: Project
          Value: Workflow
#PublicSubnet
  WorkflowPublicSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      CidrBlock: "10.0.0.0/24"
      VpcId: 
        Ref: WorkflowVpc
  WorkflowInternetGateway:
    Type: AWS::EC2::InternetGateway
  WorkflowVCPGatewayAttachment:
    DependsOn: 
      - WorkflowInternetGateway
      - WorkflowVpc
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      InternetGatewayId:
        Ref: WorkflowInternetGateway
      VpcId:
        Ref: WorkflowVpc
  WorkflowElasticIp:
    Type: AWS::EC2::EIP
    Properties:
      Domain: vpc
  WorkflowPublicSubnetRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: 
        Ref: WorkflowVpc
  PublicSubnetToRouteTable:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId:
        Ref: WorkflowPublicSubnetRouteTable
      SubnetId: 
        Ref: WorkflowPublicSubnet
  WorkflowInternetRoute:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId:
        Ref: WorkflowPublicSubnetRouteTable
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: 
        Ref: WorkflowInternetGateway
  WorkflowNat:
    DependsOn: 
      - WorkflowVCPGatewayAttachment
      - WorkflowElasticIp
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId: 
        Fn::GetAtt:
          - WorkflowElasticIp
          - AllocationId
      SubnetId:
        Ref: WorkflowPublicSubnet
#Private subnet          
  WorkflowPrivateSubnet:
    Type: AWS::EC2::Subnet
    Properties:
      CidrBlock: "10.0.1.0/24"
      VpcId: 
        Ref: WorkflowVpc
  WorkflowPrivateSubnetRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: 
        Ref: WorkflowVpc
  PrivateSubnetToRouteTable:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId:
        Ref: WorkflowPrivateSubnetRouteTable
      SubnetId: 
        Ref: WorkflowPrivateSubnet
  WorkflowNatRoute:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId:
        Ref: WorkflowPrivateSubnetRouteTable
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: 
        Ref: WorkflowNat
#Fargate:
  WorkflowFargateTask:
    Type: AWS::ECS::TaskDefinition
    Properties:
      RequiresCompatibilities: 
        - "FARGATE"
      Cpu: "256"
      Memory: "0.5GB"
      ContainerDefinitions:
        - Name: WorkflowFargateContainer
          Image: "XYZ.dkr.ecr.us-east-1.amazonaws.com/workflow:latest"
      NetworkMode: awsvpc
      ExecutionRoleArn: "arn:aws:iam::XXX:role/ecsTaskExecutionRole"

  WorkflowCluster:
    Type: AWS::ECS::Cluster
    Properties:
      ClusterName: WorkflowServiceCluster

#  WorkflowService:
#    DependsOn: 
#      - WorkflowNatRoute
#    Type: AWS::ECS::Service
#    Properties:
#      Cluster: 
#        Ref: WorkflowCluster
#      DesiredCount: 1
#      TaskDefinition:
#        Ref: WorkflowFargateTask
#      NetworkConfiguration:
#        AwsvpcConfiguration: 
#          AssignPublicIp: DISABLED
#          Subnets: 
#            - Ref: WorkflowPrivateSubnet
#      LaunchType: FARGATE

我还尝试在公用子网中设置assignpublicip:enabled,它工作得很好,但这不是我的目标。

所以,我的问题是:我的模板可以吗?这是Fargate/ECR的问题吗?

另外,调试这种行为的最佳方法是什么?似乎CloudWatch没有关于此错误的日志…