Watching AWS CloudFormation Stack Status

live display of current event status for each stack resource

Would you like to be able to watch the progress of your new CloudFormation stack resources like this? (press play)

That’s what the output of the newaws-cloudformation-stack-status command looks like when I launch a new AWS Git-backed Static Website CloudFormation stack.

It shows me in real time which resources have completed, which are still in progress, and which, if any, have experienced problems.

Background

AWS provides a few ways to look at the status of resources in a CloudFormation stack including the stream of stack events in the Web console and in the aws-cli.

Unfortunately, these displays show multiple events for each resource (e.g., CREATE_IN_PROGRESS, CREATE_COMPLETE) and it’s difficult to match up all of the resource events by hand to figure out which resources are incomplete and still in progress.

Solution

I created a bit of wrapper code that goes around the aws cloudformation describe-stack-events command. It performs these operations:

1. Cuts the output down to the few fields that matter: status, resource name, type, event time.

2. Removes all but the ost recent status event for each stack resource.

3. Sorts the output to put the resources with the most recent status changes at the top.

4. Repeatedly runs this command so that you can see the stack progress live and know exactly which resource is taking the longest.

I tossed the simple script up here in case you’d like to try it out:

GitHub: aws-cloudformation-stack-status

You can run it to monitor your CloudFormation stack with this command:

aws-cloudformation-stack-status --watch --region $region --stack-name $stack

Interrupt with Ctrl-C to exit.

Note: You will probably need to start your terminal out wider than 80 columns for a clean presentation.

Note: This does use the aws-cli, so installing and configuring that is a prerequisite.

Stack Delete Example

Here’s another example terminal session watching a stack-delete operation, including some skipped deletions (because of a retention policy). It finally ends with a “stack not found error” which is exactly what we hope for after a stack has been deleted successfully. Again, the resources with the most recent state change events are at the top.

Note: These sample terminal replays cut out almost 40 minutes of waiting for the creation and deletion of the CloudFront distributions. You can see the real timestamps in the rightmost columns.

Original article and comments: https://alestic.com/2016/11/aws-cloudformation-stack-status/