CF Nested Stack example

A Nested stack of Cloudformation templates that creates the following resources:

• VPC
  • 3 Subnets (2 Private, 1 Public and their Route Tables)
  • NAT Gateway
  • Internet Gateway
  • Security Group
• EC2 Spot Fleet Request with Autoscaling
  • 3 IAM Roles and their policies (Fleet,Autoscaling,Instance)
  • Application AutoScaling Target
    • Scaling Policies (Up/Down)
  • Instance Profile
• S3 Bucket(s)
• EC2 instance(s)

Prerequisites

• Ensure all CloudFormation template files contained in this repository are uploaded to your desired S3 bucket.
• There is a sub-folder in this repository named prerequisites, it contains some CloudFormation template files that must be run prior to running the main (root) CloudFormation stack.
  • These CloudFormation template files define the creation of macros that extend the basic CloudFormation capabilities and these macros are required by our templates.
  • NOTE: These macros only need to be created once but FOR EACH REGION that you deploy these CloudFormation templates. These macros use created lambda functions which are region dependent.

For more information on these macros, see the README in the prerequisites sub-folder.

Uploading files to S3

To upload all the necessary files to your S3 bucket, you may use the AWS console or the aws cli with the provided command structure.

aws s3 sync . "s3://${S3_BUCKET}" --profile "${AWS_PROFILE}" --include '*.json' --exclude '.git/*' --exclude '*.md' --exclude '.*' --exclude '*.bak' --exclude 'tmp/*'

NOTE: If you update the code relating to the parameters (and perhaps others), you may need to hard reload your browser before creating a stack as the AWS console caches some information and will not render the changes from the code.

Assumptions

• The same KeyPair is used to access all machines created by that resource stack.
• A single security group with SSH access attached to all the machines.
  • The CIDR range for the security group is defined by the allowedCIDR parameter (The default is from anywhere).

Variables

Before creating a CloudFormation stack, ensure you've uploaded the required files to an S3 bucket.

Name	Description
templateBucketURL	URL to an S3 Bucket, joined with template filename

The correct URL format can be attained by locating the Object URL when viewing one of the files in your S3 bucket.

Make sure to exclude the path and file name after the .com/ of the Object URL.

Insert the Object URL of the root.json file as templateBucketURL without the file-name.

For example: https://my-bucket.s3-us-west-2.amazonaws.com/
NOTE: the url must end with a forward-slash /.

VPC

Name	Description
vpcCIDR	CIDR Range for the VPC
allowedCIDR	Allowed CIDR Range to be used in the security group

Spot Fleet

Name	Description
spotFleetInstanceType	Spot Fleet Instance type. See Accelerated Computing instance types
spotFleetAllocationStrategy	Indicates how to allocate the target Spot Instance capacity across the Spot Instance pools specified by the Spot Fleet request
spotFleetKeyPairName	EC2 KeyPair name for the Spot Fleet
spotFleetMaximumCapacity	The maximum number of units to request for the Spot Fleet
spotFleetTargetCapacity	The number of units to request for the Spot Fleet
spotFleetPrice	The maximum price per unit hour that you are willing to pay for a Spot Instance. The default is the On-Demand price
spotFleetRequestType	One of [instant | maintain | request]. Spot Fleet Requests
spotFleetS3BucketName	Allow Spot Fleet instances access to the specified S3 bucket
spotFleetUserData	Commands to execute after the instance starts

Debug

Here are a few tips when trying to monitor a deploying stack, or debugging a failed one.

Monitoring

• There are 2 components to the stack view in the AWS console after deploying; the left bar containing the stack-list and on the right, the stack-details with the selected stack's details. Both have their own refresh button and they do not refresh automatically.
• You can monitor the Events tab of the stack-details component.

Debugging

• Check for errors in the Events tab of the stack-details component.
• If a component fails without a detailed error, do the following:
  • Navigate to the Resources tab.
  • Follow the Physical ID link of the failed resource.
  • Check the Events tab of this stack and look for more detailed errors.
• Check to make sure templateURL parameter is pointing to the correct bucket uses the correct syntax.
• Make sure you approved each checkbox at the end of the last page of the stack creation.