Error with ECS assuming task role

问题

I have the following piece of code in Cloudformation template that defines role with policy for my task that need to pull an image from my ECR registry:

  TaskDefinition:
    Type: 'AWS::ECS::TaskDefinition'
    DependsOn:
      - TaskPolicy0
    Properties:
      Family: !Sub '${EcsTaskDefFamily}'
      TaskRoleArn: !Ref EcsTaskRole
      ContainerDefinitions:
        - Name: !Ref NodeContName
          Essential: 'true'
          Image: !Ref ImageFullName     ### PULLED IMAGE
          Memory: !Ref ContainerMemory
          MemoryReservation: !Ref ContainerMemoryReservation
          PortMappings:
            - ContainerPort: !Ref NodeContainerPort
              HostPort: !Ref NodeHostPort
              Protocol: tcp
  EcsTaskRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - ecs-tasks.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: !Ref EcsTaskRolePath
  TaskPolicy0:
    Type: 'AWS::IAM::Policy'
    Properties:
      PolicyName: ecr-readonly
      PolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Action:
              - 'ecr:GetAuthorizationToken'
              - 'ecr:BatchCheckLayerAvailability'
              - 'ecr:GetDownloadUrlForLayer'
              - 'ecr:GetRepositoryPolicy'
              - 'ecr:DescribeRepositories'
              - 'ecr:ListImages'
              - 'ecr:DescribeImages'
              - 'ecr:BatchGetImage'
            Resource: '*'
      Roles:
        - !Ref EcsTaskRole

But when I run my Cloudformation template I get the following error:

What is that? I have defined trust policy. I didn't defined IAM Role for Cloudformation but I am running this template from my Admin acc that has following permissions:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": "*",
            "Resource": "*"
        }
    ]
}

EDIT

When I change my EcsTaskRolePath from "ecs/services/tasks/" to "/" (the same path that my Admin user has which I use to start the stack creation) then the error disappears and everything is fine. What is the problem? And can someone give me some info about this IAM paths, because all I found is single page on docs?

来源：https://stackoverflow.com/questions/51810911/error-with-ecs-assuming-task-role