Could not create AWS::ECS::Service via cloudformation yaml, got Model validation failed

Question

During creation of AWS::ECS::Service via cloudformation i got the error: Model validation failed

The error is related to #HealthCheckGracePeriodSeconds and some other properties. Error detail is: expected type: Number, found: String.

In yaml it is already a number. It's not clear to me whats going wrong. Already tried to desclare it as string or as parameter with type Number.

I need some hint because i am stuck in the muck at this point.

Error is:

Model validation failed 
    (
    #/HealthCheckGracePeriodSeconds: expected type: Number, found: String 
    #/DesiredCount: expected type: Number, found: String 
    #/DeploymentConfiguration/MaximumPercent: expected type: Number, found: String 
    #/DeploymentConfiguration/MinimumHealthyPercent: expected type: Number, found: String
    )

Definition in template.yaml is:

ServiceDefinition:
  Type: AWS::ECS::Service
  Properties:
    ServiceName: !Ref ServiceName
    Cluster: !Ref ClusterName
    TaskDefinition: !Ref TaskDefinition
    DeploymentConfiguration:
      MinimumHealthyPercent: 100
      MaximumPercent: 200
    DesiredCount: 1
    HealthCheckGracePeriodSeconds: 60
    LaunchType: FARGATE
    NetworkConfiguration:
      AwsVpcConfiguration:
        AssignPublicIP: ENABLED
        SecurityGroups: !FindInMap [Env2SecurityGroups, !Ref AWS::AccountId, securitygroup]
        Subnets: !FindInMap [Env2PublicSubnets, !Ref AWS::AccountId, subnets]

Answer 1

The error was caused because SecurityGroups and Subnets resulted in a wrong format.

To extract subnets and securitygroups the FindInMap function was used. It is necessary that this result is a list. This can be achieved using the Split function.

The wrong format unfortunately leads to a completely misleading error message.

Declare mappings like this:

Mappings
  Env2SecurityGroups:
    '111111111111':
      securitygroup: 'sg-1111111111111111'
    '222222222222':
      securitygroup: 'sg-2222222222222222'
    '333333333333':
      securitygroup: 'sg-3333333333333333'

  Env2PublicSubnets:
    '111111111111':
      subnets: subnet-1111111111111111,subnet-22222222222222222,subnet-33333333333333333
    '222222222222':
      subnets: subnet-1111111111111111,subnet-22222222222222222,subnet-33333333333333333
    '333333333333':
      subnets: subnet-1111111111111111,subnet-22222222222222222,subnet-33333333333333333

Use !Split combined with !FindInMap to get a list:

SecurityGroups: !Split [",", !FindInMap [ Env2SecurityGroups, !Ref AWS::AccountId, securitygroup] ]
Subnets: !Split [",", !FindInMap [ Env2PublicSubnets, !Ref AWS::AccountId, subnets] ]