I'm new to AWS and trying to navigate my way through some challenges. I have an application that's running off a Docker image sourced from GitHub. The URL for the image remains the same, so I can't create a changeset in my CloudFormation template, but the actual Docker build has been updated. I'm looking for guidance on how to effectively update my web app under these circumstances. It seems like I need a way to notify EC2 that the app has changed, even when it can't detect any changes on its own. Would simply rebooting the EC2 instance be the correct approach? I'm trying to get a better grasp of web app terminology and appreciate any help!
3 Answers
To start with, you should tag your Docker images with a version number. That way, CloudFormation can recognize the updated images. If you're using EC2, simply changing the image in the user data won't do the trick because CloudFormation will see no difference and won't trigger an update. You might look into using cfn-hup to handle updates. Plus, remember that just updating the image version won't automatically restart your instance either—it's a bit more complex!
Rebooting the EC2 instance alone won't pull the new Docker image; it'll just restart the current instance setup. You need to log into your EC2 instance, pull the latest image, and restart your container. Here’s what you’d typically do: `docker pull :latest`, `docker-compose down`, then `docker-compose up -d`. For automation, consider using AWS CodeDeploy or a script that will pull and restart whenever you push changes to your GitHub repo.
Without knowing your exact setup, but based on your experience level, it seems like you might want to think about how your architecture ties into CloudFormation. Remember, CloudFormation is primarily for managing infrastructure, not directly for application updates. If you find it too convoluted, AWS Elastic Beanstalk might be a simpler way to manage your application and its infrastructure. AWS documentation is very comprehensive, so diving into that might also help you find a clearer path forward!
Thanks for the tip! So if I were to change my command to include a version like `ghcr.io//:v2`, I still have to manually restart it?