Batch and UserData synths ok but fails deploy with: "Operation failed, ComputeEnvironment went INVALID with error: CLIENT_ERROR - Launch Template UserData is not MIME multipart format"

The context for this issue is well described in the Gitter aws-cdk channel over here, along with the tests performed by @skinny85, @reisingerf and myself:

https://gitter.im/awslabs/aws-cdk?at=5e54579d9aeef6523217b25f

Reproduction Steps

Given the following snippet, as described in the Gitter thread:

const vpc = ec2.Vpc.fromLookup(this, 'Vpc', {
            isDefault: true,
        });

        const batch_instance_role = new iam.Role(this, 'BatchInstanceRole', {
            roleName: 'UmccriseBatchInstanceRole',
            assumedBy: new iam.CompositePrincipal(
                new iam.ServicePrincipal('ec2.amazonaws.com'),
                new iam.ServicePrincipal('ecs.amazonaws.com'),
            ),
            managedPolicies: [
                iam.ManagedPolicy.fromAwsManagedPolicyName('service-role/AmazonEC2RoleforSSM'),
                iam.ManagedPolicy.fromAwsManagedPolicyName('service-role/AmazonEC2ContainerServiceforEC2Role')
            ],
        });
        const spotfleet_role = new iam.Role(this, 'AmazonEC2SpotFleetRole', {
            assumedBy: new iam.ServicePrincipal('spotfleet.amazonaws.com'),
            managedPolicies: [
                iam.ManagedPolicy.fromAwsManagedPolicyName('service-role/AmazonEC2SpotFleetTaggingRole'),
            ],
        });
        const batch_service_role = new iam.Role(this, 'BatchServiceRole', {
            assumedBy: new iam.ServicePrincipal('batch.amazonaws.com'),
            managedPolicies: [
                iam.ManagedPolicy.fromAwsManagedPolicyName('service-role/AWSBatchServiceRole'),
            ],
        });
        const batch_instance_profile = new iam.CfnInstanceProfile(this, 'BatchInstanceProfile', {
            instanceProfileName: 'UmccriseBatchInstanceProfile',
            roles: [batch_instance_role.roleName],
        });

        const launch_template = new ec2.CfnLaunchTemplate(this, 'LaunchTemplate', {
            launchTemplateData: {
                userData: core.Fn.base64(`
                    MIME-Version: 1.0
                    Content-Type: multipart/mixed; boundary="==MYBOUNDARY=="

                    --==MYBOUNDARY==
                    Content-Type: text/x-shellscript; charset="us-ascii"

                    #!/bin/bash          
                    echo Hello

                    --==MYBOUNDARY==--
                `),
            },
            launchTemplateName: 'UmccriseBatchComputeLaunchTemplate',
        });
        new batch.CfnComputeEnvironment(this, 'UmccriseBatchComputeEnv', {
            type: 'MANAGED',
            serviceRole: batch_service_role.roleArn,
            computeResources: {
                type: 'SPOT',
                maxvCpus: 128,
                minvCpus: 0,
                desiredvCpus: 0,
                imageId: 'ami-05c621ca32de56e7a',
                launchTemplate: {
                    launchTemplateId: launch_template.ref,
                    version: launch_template.attrLatestVersionNumber,
                },
                spotIamFleetRole: spotfleet_role.roleArn,
                instanceRole: batch_instance_profile.instanceProfileName!,
                instanceTypes: ['optimal'],
                subnets: [vpc.publicSubnets[0].subnetId],
                securityGroupIds: ['sg-0a5cf974'],
                tags: { 'Creator': 'Batch' },
            }
        });

For more context, there’s this other working example too:

https://github.com/awslabs/aws-batch-helpers/issues/5#issue-425133706

Error Log

This:

Operation failed, ComputeEnvironment went INVALID with error: CLIENT_ERROR - Launch Template UserData is not MIME multipart format

Coupled with the deploy time error (in Python, ask @skinny85 for the TypeScript counterpart):

 6/10 | 10:01:20 AM | UPDATE_FAILED        | AWS::Batch::ComputeEnvironment        | UmccriseBatchComputeEnv Operation failed, ComputeEnvironment went INVALID with error: CLIENT_ERROR - Launch Template UserData is not MIME multipart format
        /Users/romanvg/.miniconda3/envs/cdk/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7838:49
        \_ Kernel._wrapSandboxCode (/Users/romanvg/.miniconda3/envs/cdk/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:8298:20)
        \_ Kernel._create (/Users/romanvg/.miniconda3/envs/cdk/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7838:26)
        \_ Kernel.create (/Users/romanvg/.miniconda3/envs/cdk/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7585:21)
        \_ KernelHost.processRequest (/Users/romanvg/.miniconda3/envs/cdk/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7372:28)
        \_ KernelHost.run (/Users/romanvg/.miniconda3/envs/cdk/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7312:14)
        \_ Immediate._onImmediate (/Users/romanvg/.miniconda3/envs/cdk/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7315:37)
        \_ processImmediate (internal/timers.js:456:21)

Environment

• CLI Version : 1.25.0 (build 5ced526)
• Framework Version: 1.25.0 (build 5ced526)
• OS : MacOS Catalina 10.15.3
• Language : Python and Typescript

This is 🐛 Bug Report

[alexiswl]

After much playing around I’ve managed to see a workaround for a python deployment. Reading in the user data from a file is better than using a multi-line string.

Part 1: Read in the user data

with open("user_data/user_data.txt", 'r') as user_data_h:
            user_data = user_data_h.read()

Part 2: Assign as a Userdata object with the custom method

user_init = ec2.UserData.custom(user_data)

Part 3: Add to launch_template_data dict

The render magically gets rid of the lines attribute in the stack and the base64 re-encodes it as appropriate

launch_template_data = {
     "UserData": core.Fn.base64(user_init.render())
}

Part 4: Initialise the launch template

launch_template = ec2.CfnLaunchTemplate(self, "LaunchTemplate", launch_template_name="UmccriseBatchComputeLaunchTemplateDev")

Part 5: Override the launch template property

Adding in userdata in the previous step under the kwarg launch_template_data doesn’t seem to work so we override the property using the add_property_override instead

launch_template.add_property_override("LaunchTemplateData", launch_template_data)

Part 6: Validate

Our launch template should look like this after running cdk synth

LaunchTemplate:
    Type: AWS::EC2::LaunchTemplate
    Properties:
      LaunchTemplateData:
        UserData:
          Fn::Base64: >-
            MIME-Version: 1.0

            Content-Type: multipart/mixed; boundary="==MYBOUNDARY=="


            --==MYBOUNDARY==

            Content-Type: text/x-shellscript; charset="us-ascii"


            #!/bin/bash

            echo Hello


            --==MYBOUNDARY==--

[stephenhibbert]

@brainstorm - I believe the CLIENT_ERROR issue is in the UserData is to do with whitespace. My advice is to copy exactly one of the examples here: https://docs.aws.amazon.com/batch/latest/userguide/launch-templates.html and just modify the commands, leaving the whitespace exactly the same.