Instance Store AMI from a customized EBS-backed instance

Question

Sorry if this supposed to be easily understood from the docs, but I didn't - if I spin up an EC2 instance using one of the easily available Ubuntu EBS-boot AMI's, install a bunch of stuff and move some files around under "/", and then I create an Instance-Store AMI using ec2-bundle-vol, will the data that was actually residing on the EBS volume mounted at "/" make it into the AMI?

Considering that from a user point-of-view, I would expect to find the same things under "/" in a future spin-up of my custom AMI, that I had in the original instance. It would also kind of make sense for Amazon to take a snapshot of the "/" folder to create my AMI (otherwise, what would one take a snapshot of?!), even though the AMI itself is Instance Store based while the original instance was EBS-backed.

Please help me understand this.

What I'm referring to:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/creating-snapshot-s3-linux.html
http://docs.aws.amazon.com/AWSEC2/latest/CommandLineReference/CLTRG-ami-bundle-vol.html

Thanks.

Answer 1

Yes, the data on the EBS volume residing on the root volume will make it to the AMI.

From AWS documentation : "By default, the AMI bundling process creates a compressed, encrypted collection of files in the /tmp directory that represent your root volume." http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/creating-an-ami-instance-store.html

It will of course exclude the private keys and bash history... unless you use the --no-filter option : http://docs.aws.amazon.com/AWSEC2/latest/CommandLineReference/CLTRG-ami-bundle-vol.html

Procedure for the conversion:

It’s basically the procedure to create an instance store-backed AMI that needs to be followed. You will have to indicate a compatible kernel when registering the AMI though.

1. set up the EC2 CLI tools on the instance you want to convert (if not already installed)

2. get a X.509 certificate and private key (it can be self signed: openssl req -x509 -newkey rsa:2048 -keyout private-key.pem -out cert.pem -days 385 -nodes)

3. connect to the instance you want to convert

4. move your X.509 certificate and private key to /tmp/ mv private-key.pem cert.pem /tmp/

5. create the folder /tmp/out/ mkdir /tmp/out

6. create your bundle: ec2-bundle-vol -k /tmp/private-key.pem -c /tmp/cert.pem -u <account_id> -r x86_64 -d /mnt/out See the documentation for more details http://docs.aws.amazon.com/AWSEC2/latest/CommandLineReference/CLTRG-ami-upload-bundle.html You may need to hange the block device mapping (e.g. -B root=/dev/sda1)

7. upload the bundle to a S3 bucket: ec2-upload-bundle -b <bucket_name>/<bundle_folder>/<bundle_name> -a <access_key> -s <secret_key> -m /tmp/out/image.manifest.xml --region <aws_region>

8. register the AMI: ec2-register --kernel <kernel_id> --region <aws_region> --name “<ami_name>" --description “<ami_description>" <bucket_name>/<bundle_folder>/<bundle_name>/image.manifest.xml -O <access_key> -W <secret_key> See the documentation for more details: http://docs.aws.amazon.com/AWSEC2/latest/CommandLineReference/ApiReference-cmd-RegisterImage.html (see --root-device-name and -b options)

The devices mapping and volumes organisation are different between ebs-backed and instance store-backed instances so you need to make sure everything is where the system expects it to be