dmelo.github.io

Export Amazon EC2 instance to VirtualBox

Let’s say that you want/need to export your running EC2 instance to another platform. It may be a VirtualBox, VMWare, QEmu virtual machine or perhaps a physical machine. The tool provided by Amazon to do a job like this is very restricted:

• the EC2 instance may have only one EBS volume attached to it;
• there is no way to do it using only the Web console, you have to use the cli tool;
• you can only export instances you have previously imported.

The approach proposed on this post doesn’t rely on that Amazon tool and, therefore is not bound by those restrictions. The basic idea is:

• attach the EBS volume of the target machine on another instance;
• use dd to dump the volume into a file;
• download/transfer that file to a more convenient place;
• reconfigure the image so that it works outside of the cloud;
• convert the raw image to the desired VM.

The following sections go in details about how to accomplish each described step.

Before executing the procedure

Bear in mind that the end result will be the EC2 instance running on VirtualBox (or something similar). You will probably want to log on the tty console. By default, you access your EC2 instance through ssh, using certificates, so the standard user (in my case fedora) doen’t have a password. Log into your machine and set a password for that user:

sudo passwd fedora

Dump the EBS volume into a downloadable file

On the Amazon console, do the following steps:

1. turn off the machine that will be cloned;
2. detach the root volume from that machine;
3. attach the volume on another (auxiliary) machine (it must be attached as a secondary volume);
4. install lzma (some distros doesn’t include it by default);
5. log into the auxiliary machine and dump the EBS volume into a file.

Considering it is attached as /dev/xvdf, you can use the following command to accomplish that last step.

dd if=/dev/xvdf | lzma -z -0 > /opt/ec2.img.lzma

This command might take a while. After it is done, you can copy /opt/ec2.img.lzma to your local machine or any other convenient place.

• Obs.: If you rather not turn off the EC2 instance, during this procedure, you can try to make a snapshot of the root EBS and create another EBS from it. Then, perform the steps on this section on that cloned EBS.

Reconfigure the image so that it works outside of the cloud

This step ended up being easier than I had expected. Start by uncompressing the image

lzma -cd ec2.img.lzma > ec2.img

We need to know the offset for the beginning of the root partition, inside the block file. Use fdisk:

fdisk -l ec2.img

The offset is equal to Start times sector size. In my case 2048 times 512, which equals 1048576. Now, I can mount the img file as a partition:

sudo mount -o loop,offset=1048576 ec2.img /mnt/disk

As root, use chroot to change the base to the ec2 system. It is also necessary to disable the cloud specific services. The last thing I had to do was to include a line on /etc/security/access to enable login through the tty console.

chroot /mnt/disk;
rm /etc/systemd/system/multi-user.target.wants/cloud*;
echo "+ : ALL : ALL" >> /etc/security/access.conf;

It is also a good idea to review your /etc/fstab to remove entries about partitions that won’t be there (at least at first). Now, get off chroot and unmount the partition:

exit;
umount /mnt/disk;

Convert the raw image to the desired VM

In this post, I show how to make a VirtualBox VM out of it. So, this last section varies accordingly with your goal. To make the VirtualBox VM, start by converting from raw to VDI using VBoxManage:

VBoxManage convertfromraw ec2.img ec2.vdi --format VDI

Now you can use the VirtualBox GUI to create a new VirtualBox machine. Instead of asking to create a new disk, use the newly created ec2.vdi.

And it is done!! Now you can start your VM and have fun with it.