Using cfn-modules outside docker env

Rapid Docker on AWS
#1

Hi,

following on from the book I am trying to run some of the cfn-modules examples up, with a view to customising them for our application. I have cloned the repo and followed the example commands but they all seem to fail on VPC creation, specifically on creating the subnets, with the message

 {
            "StackId": "arn:aws:cloudformation:eu-west-2:496345731537:stack/fargate-alb-single-container-example/62a382d0-62e4-11ea-8ae8-0a7f7081acf8",
            "EventId": "Vpc-CREATE_FAILED-2020-03-10T15:34:17.790Z",
            "StackName": "fargate-alb-single-container-example",
            "LogicalResourceId": "Vpc",
            "PhysicalResourceId": "arn:aws:cloudformation:eu-west-2:496345731537:stack/fargate-alb-single-container-example-Vpc-1N3C7PEEZ486L/762eb720-62e4-11ea-b835-060395953c4e",
            "ResourceType": "AWS::CloudFormation::Stack",
            "Timestamp": "2020-03-10T15:34:17.790000+00:00",
            "ResourceStatus": "CREATE_FAILED",
            "ResourceStatusReason": "Embedded stack arn:aws:cloudformation:eu-west-2:496345731537:stack/fargate-alb-single-container-example-Vpc-1N3C7PEEZ486L/762eb720-62e4-11ea-b835-060395953c4e was not successfully created: The following resource(s) failed to create: [SubnetBPrivate, SubnetAPrivate, SubnetAPublic, SubnetCPublic, SubnetCPrivate, SubnetBPublic]. ",
            "ResourceProperties": "{\"TemplateURL\":\"https://s3.eu-west-2.amazonaws.com/docker-on-aws-derbex/7f02bffc978183451b50c5619681ce0c.template\",\"Parameters\":{\"AlertingModule\":\"fargate-alb-single-container-example-Alerting-18SXWEM5M6PBL\",\"FlowLog\":\"false\",\"S3Endpoint\":\"false\",\"DynamoDBEndpoint\":\"false\",\"NatGateways\":\"false\"}}"
        },

my account has admin privileges, any ideas gratefully accepted.

#2

hi!

could you check the error messages of the nested cloudformation stacks whre the subnets are created? there might be an issue with a missing availability zone.

Thanks
Michael

#3

Hi Michael,

thanks for the reply, this seems to be error in the VPC stack

    {
        "StackId": "arn:aws:cloudformation:eu-west-2:496345731537:stack/fargate-alb-single-container-example-Vpc-11ZHK47JKFWKJ/8c234f40-6371-11ea-9cf3-02949b77ae4a",
        "EventId": "SubnetBPrivate-CREATE_FAILED-2020-03-11T08:24:05.808Z",
        "StackName": "fargate-alb-single-container-example-Vpc-11ZHK47JKFWKJ",
        "LogicalResourceId": "SubnetBPrivate",
        "PhysicalResourceId": "",
        "ResourceType": "AWS::CloudFormation::Stack",
        "Timestamp": "2020-03-11T08:24:05.808000+00:00",
        "ResourceStatus": "CREATE_FAILED",
        "ResourceStatusReason": "Template format error: YAML not well-formed. (line 62, column 16)",
        "ResourceProperties": "{\"TemplateURL\":\"https://s3.eu-west-2.amazonaws.com/docker-on-aws-derbex/b84a6b41a26a8a221609cb61eb28c45d.template\",\"Parameters\":{\"AZChar\":\"B\",\"Reach\":\"private\",\"SubnetCount\":\"6\",\"AZIndex\":\"1\",\"VpcPlainModule\":\"fargate-alb-single-container-example-Vpc-11ZHK47JKFWKJ-VpcPlain-NM0IAYHK0MQ0\",\"SubnetIndex\":\"3\"}}"
    },

I had a look in the template that was pushed to S3 and the offending section seems to be in the CIDR block here

Resources:

Subnet:
Type: AWS::EC2::Subnet
Properties:
AvailabilityZone:
Fn::Select:
- Ref: AZIndex
- Fn::GetAZs: ‘’
CidrBlock:
Fn::Select:
- Ref: SubnetIndex
- Fn::Cidr:
- {Fn::ImportValue: {Fn::Sub: ‘${VpcPlainModule}-CidrBlock’}}
- Ref: SubnetCount
- 12

#4

What#s the version of AWS CLI you are using? Could you post the output of aws --version?

This might be related to https://github.com/cfn-modules/vpc-subnet/issues/1

#5

It is version 2

aws-cli/2.0.2 Python/3.7.3 Linux/4.15.0-88-generic botocore/2.0.0dev6

#6

Are you able to downgrade to v1 to see if that fixes the issue?

#7

That fixes it.

I downgraded to aws-cli/1.18.18 Python/3.6.9 Linux/4.15.0-88-generic botocore/1.15.18

I have a couple of other questions, if you don’t mind, but I will raise them in new topics.

#8