Creating an exactly similar snapshot of your existing running EC2 ami instance

Some rights reserved by Martin Fisch

Everything was going pretty well on the existing EC2 instance, when the developers offshore came up with another version of the existing CMS, which needed to be tested along with the existing CMS. One way was to have another virtual host created for the new CMS but there were some existing resources that could not be shared between the two CMSs.

The only way out of this was to have another instance with the new CMS version. Installing the same applications in the new instance was surely time consuming, this would take another day for sure. So we came up with the idea of creating a snapshot of the existing instance.

Caution: If you only try to create a copy of the existing instance you will only get the Instance along with the OS not the applications along with it. To create the exact similar copy of the instance the steps are slightly different.

Steps to create an exact similar copy are as follows:

1. Create an EBS volume using the web interface. You may use Amazon Documentation for this.
2. Attach this volume to your existing instance. note down the volume and the device id. (Vol -123456, /dev/sdg) Documentation
3. Next you would need is a file system to work on, on the attached volume. Log in to your instance, and use the commands below
• mkfs.ext3 /dev/sdg
• tune2fs -c 0 /dev/sdg
4. Now mount this disk
• mkdir /mnt/data
• mount /dev/sdg /mnt/ebs
5. Now you can copy all the data to your EBS volume but before you do that, shutdown the running services that may harm the data, I stopped MySQL Apache, ElasticSearch etc on my instance. To copy all data use rsync : This will sync all the data in your present volume to the new volume.
• rsync -avx --exclude /mnt / /mnt/ebs //you may use --exclude <directory name> to exclude any directories
6. This should take long time depending on how big the data is. Once the copying is done, Unmount the volume by:
• umount /dev/sdg
• You may want to check the volume space by df -h
7. Detach the volume for the present instance from the console. Documentation
8. Right click on the volume and click on create AMI image. When the image is created. Right click on it and click on Launch Instance.

You now have an exact copy of your old instance running.