Using Ubuntu Images on AWS "Free Tier"

[Update 2011-01-20]

There are now official Ubuntu AMIs that fit into the Free Tier disk requirements. You can get a list of the AMIs for 10.04 or 10.10.

This article is still useful as documentation, but is not necessary if you only want to use Ubuntu on Amazon's Free Tier.

Amazon AWS recently announced an AWS Free Usage Tier. The summary of which is that new AWS customers can run a t1.micro instance 24x7 for the next year and pay nothing (or at least very little).

There are various restrictions on what you get for free, but the most interesting to the Ubuntu images is:

10 GB of Amazon Elastic Block Storage, plus 1 million I/Os, 1 GB of snapshot storage, 10,000 snapshot Get Requests and 1,000 snapshot Put Requests*

The Official Ubuntu Images have a 15GB root filesystem. What that means is if you're using any of our official images (10.04, 10.10), then you will be charged for 5GB of provisioned storage per month. In the us-east-1 region that would be $0.50/month. In other regions, that would be $0.55/month.

This issue has been raised on the AWS Discussion Forums, but it seems like Amazon is not willing to budge.

Similarly, bug 670161 was opened requesting "10GB root partition for EBS boot AMIs on EC2". If you're interested in following this discussion, subscribe yourself to that bug. I will make sure that it is kept up to date.

I don't want to comment right now on whether or not we will release future EBS root AMIs of 10.04 and and 10.10 with a 10GB filesystem instead of a 15G filesystem. What I do want to discuss is how you can create your own AMI that has a 10G (or smaller) root filesystem, which will perform otherwise identically to the official images.

If you want to use Ubuntu on the Amazon Free Tier *right now*, then you can follow these instructions, which assume you have the ec2-api-tools correctly configured on your laptop. And you have a keypair named "mykey" available in the target region.

In the code (shell prompt) snippits below, '$' prompt indicates command run on my laptop. '%' prompt indicates command run on the ec2 instance. lines beginning with a '#' are comments.

Launch an instance to work with:

# us-east-1 ami-548c783d canonical ebs/ubuntu-maverick-10.10-amd64-server-20101007.1
$ ec2-run-instances --region us-east-1 --instance-type t1.micro \
--key mykey ami-548c783d
$ iid=i-1855ea75
$ zone=$(ec2-describe-instances $iid |
awk '-F\t' '$2 == iid { print $12 }' iid=${iid} )
$ echo ${zone}
us-east-1d
$ host=$(ec2-describe-instances $iid |
awk '-F\t' '$2 == iid { print $4 }' iid=${iid} )
$ echo ${host}
ec2-174-129-61-12.compute-1.amazonaws.com


create a volume in correct zone of the desired size to attach to the instance. Change '10' to '5' if you wanted a 5GB root filesystem.

$ ec2-create-volume --size 10 --availability-zone ${zone}
$ vol=vol-c64d55af
$ ec2-attach-volume --instance ${iid} --device /dev/sdh ${vol}


Then, ssh to ubuntu@${host}, and download the uec reference image and extract it. Below, I've downloaded the i386 image for maverick. You could browse through at http://uec-images.ubuntu.com/releases/10.10/release/ and find an amd64 image or a 10.04 base image.

% sudo chown ubuntu:ubuntu /mnt
% cd /mnt
% url=http://uec-images.ubuntu.com/releases/10.10/release/ubuntu-10.10-server-uec-i386.tar.gz
% tarball=${url##*/}
% wget ${url} -O ${tarball}
% tar -Sxvzf ${tarball}
maverick-server-uec-i386.img
maverick-server-uec-i386-vmlinuz-virtual
maverick-server-uec-i386-loader
maverick-server-uec-i386-floppy
README.files
% img=maverick-server-uec-i386.img
% mkdir src target


create target filesystem, mount the attached volume, and copy source filesystem contents to target filesystem using rsync.

% sudo mount -o loop,ro ${img} /mnt/src
% sudo mkfs.ext4 -L uec-rootfs /dev/sdh
% sudo mount /dev/sdh /mnt/target
# the rsync could take quite a while. for me it took 22 seconds.
% sudo rsync -aXHAS /mnt/src/ /mnt/target
% sudo umount /mnt/target
% sudo umount /mnt/src


Now, back on the laptop, snapshot the volume.

$ ec2-create-snapshot ${vol}
$ snap=snap-b97dfdd3
# now you have to wait for snapshot to be 'completed'
$ ec2-describe-snapshots ${snap}
SNAPSHOT snap-b97dfdd3 vol-c64d55af completed 2010-11-03T17:31:52+0000 100% 950047163771 10


Turn the contents of that volume into an AMI. Note, you must set 'arch', 'rel', and 'region' correctly. Then, we use that information to get the aki associated with the most recent released Ubuntu image.


$ rel=maverick; region=us-east-1; arch=i386; # arch=amd64
$ [ $arch = amd64 ] && xarch=x86_64 || xarch=${arch}
$ qurl=http://uec-images.ubuntu.com/query/${rel}/server/released.current.txt
$ aki=$(curl --silent "${qurl}" |
awk '-F\t' '$5 == "ebs" && $6 == arch && $7 == region { print $9 }' \
arch=$arch region=$region )
$ echo ${aki}
aki-407d9529
$ ec2-register --snapshot ${snap} \
--architecture=${xarch} --kernel=${aki} \
--name "my-ubuntu-${rel}" --description "my-ubuntu-${rel}"
IMAGE ami-4483742d
$ ami=ami-4483742d


Clean up your instance and volume

$ ec2-detach-volume ${vol}
$ ec2-terminate-instances ${iid}
$ ec2-delete-volume ${vol}


And now run your instance

$ ec2-run-instances --instance-type t1.micro ${ami}
$ ssh ubuntu@
% sudo apt-get update && sudo apt-get dist-upgrade
# if you got a new kernel (linux-virtual package), then you will
# need to reboot
% sudo reboot


Now, your newly created image has filesystem contents that are identical to those of the official Ubuntu images, but with a 10G filesystem.

Once you've launched your image, you can actually clean up the snapshot and the AMI id that you launched. To do that:

ec2-deregister ${ami}
ec2-delete-snapshot ${snap}


The cost of the above operations will probably be on the order of pennies, and will remove the costs you would have incurred due to having 15G root volume.