We have some servers on Amazon EC2, and we back up the entire file system using cumulus. I'm wondering how to restore the entire file system from cumulus on to an EC2 instance - we need to do a test restore. Some ways I can imagine:
- Amazon has some way of filling the root filesystem before boot.
- Set up an instance and restore the files to /tmp. To copy it all to root I'd have to stop the instance running, otherwise there would be problems with open files, but I'm not sure how to access the filesystem of a stopped instance.
And, yes, I am new to EC2, so I may be missing some obvious tools.
First of all, backing up the root file system of an EC2 instance should be done with the EC2 tools of bundling for ephemeral AMI's and snapshoting for EBS backed AMI's. Cumulus only makes sense for file systems not already in the cloud. Since EC2 instances have built in tools for backing up to S3 that are well integrated with launching the backups as instances, those are the tools of choice.
For conceptual reference, your restore from cumulus would have to be like setting up a new AMI from scratch, say of a new distro. You would create a volume and attach it to an instance, restore the file system to that mount, then detach and snapshot the mount and turn the snapshot into an instance by registering it as a root file system. Alternatively for an ephemeral backed instance you would use the bundle tools to create the AMI from the restored file structure.