Create AMI image as part of a cloudformation stack

Question

I want to create an EC2 cloudformation stack which basically can be described in the following steps:

1.- Launch instance

2.- Provision the instance

Answer 1

While @wjdordan's solution is good for simple use cases, updating the User Data will not update the AMI.

(DISCLAIMER: I am the original author) cloudformation-ami aims at allowing you to declare AMIs in CloudFormation that can be reliably created, updated and deleted. Using cloudformation-ami You can declare custom AMIs like this:

MyAMI:
  Type: Custom::AMI
  Properties:
    ServiceToken: !ImportValue AMILambdaFunctionArn
    Image:
      Name: my-image
      Description: some description for the image
    TemplateInstance:
      ImageId: ami-467ca739
      IamInstanceProfile:
        Arn: arn:aws:iam::1234567890:instance-profile/MyProfile-ASDNSDLKJ
      UserData:
        Fn::Base64: !Sub |
          #!/bin/bash -x
          yum -y install mysql # provisioning example
          # Signal that the instance is ready
          INSTANCE_ID=`wget -q -O - http://169.254.169.254/latest/meta-data/instance-id`
          aws ec2 create-tags --resources $INSTANCE_ID --tags Key=UserDataFinished,Value=true --region ${AWS::Region}
      KeyName: my-key
      InstanceType: t2.nano
      SecurityGroupIds:
      - sg-d7bf78b0
      SubnetId: subnet-ba03aa91
      BlockDeviceMappings:
      - DeviceName: "/dev/xvda"
        Ebs:
          VolumeSize: '10'
          VolumeType: gp2