Sometimes CloudFormation stacks get stuck and report UPDATE_ROLLBACK_FAILED. You can ask AWS support to unstuck it but here is how to do it yourself through the command line.

# make sure you have AWS CLI 1.10+
aws --version
pip install --upgrade awscli
aws cloudformation continue-update-rollback --stack-name

Sources

• AWS Docs - Continue Rolling Back an Update
• AWS CLI Docs - continue-update-rollback