In previous posts, I shared how to use Ubuntu Cloud Images and eustore with Eucalyptus and AWS.  This blog entry will focus on how to use these assets to create EBS-backed EMIs in 12 steps.   These steps can be used on AWS as well, but instead of creating an instance store-backed AMI first, Ubuntu has already provided AMIs that can be used as the building block instance on AWS.  Let’s get started.

Prerequisites

On Eucalyptus and AWS, it is required the user has the appropriate IAM policy in order to perform these steps.  The policy should contain the following EC2 Actions at a minimum:

• RunInstances
• AttachVolume
• AuthorizeSecurityGroupEgress
• AuthorizeSecurityGroupIngress
• CreateKeyPair
• CreateSnapshot
• CreateVolume
• DescribeImages
• DescribeInstances
• DescribeInstanceStatus
• DescribeSnapshots
• DetachVolume
• RegisterImage

In addition, the user needs an access key ID and secret key.  For more information, check out the following resources:

• Administering Access Keys for IAM Users – AWS IAM Using IAM
• Working with User Credentials – Eucalyptus Administration Guide

This entry also assumes Eucalyptus euca2ools are installed on the client machine.

The 12 Steps

Although the Ubuntu Cloud Image used in this entry is Ubuntu Precise (12.04) LTS, any of of the maintained Ubuntu Cloud images can be used.

1. Use wget to download tar-gzipped precise-server-cloudimg:

   $ wget http://cloud-images.ubuntu.com/precise/current/precise-server-cloudimg-amd64.tar.gz

2. After setting the EC2_ACCESS_KEY, EC2_SECRET_KEY, and EC2_URL, use eustore-install-image to an instance stored-backed EMI:

   $ eustore-install-image -t precise-server-cloudimg-amd64.tar.gz \
   -b ubuntu-latest-precise-x86_64 --hypervisor universal \
   -s "Ubuntu Cloud Image - Precise Pangolin - 12.04 LTS"

3. Create a keypair using euca-create-keypair, then use euca-run-instances to launch an instance from the EMI returned from eustore-install-image. For example:

   $ euca-run-instances -t m1.medium \
   -k account1-user01 emi-5C8C3909

4. Use euca-create-volume to create a volume based upon the size of how big you want the root filesystem to be.  The availability zone (-z option) will be based on if you are using Eucalyptus or AWS:

   $ euca-create-volume -s 6 \
   -z LayinDaSmackDown

5. Using euca-attach-volume, attach the resulting volume to the running instance. For example:

   $ euca-attach-volume -d /dev/vdd \
   -i i-839E3FB0 vol-B5863B3B

6. Use euca-authorize to open SSH access to the instance, SSH into the instance, then use wget to download the Ubuntu Precise Cloud Image (qcow2 format):

   $ ssh -i account1-user01.priv ubuntu@euca-10-104-7-10.eucalyptus.euca-hasp.eucalyptus-systems.com
   # sudo -s
   # wget http://cloud-images.ubuntu.com/precise/current/precise-server-cloudimg-amd64-disk1.img

7. Install qemu-utils:

   # apt-get install -y qemu-utils

8. Use qemu-img to convert image from qcow2 to raw:

   # qemu-img convert \
   -O raw precise-server-cloudimg-amd64-disk1.img precise-server-cloudimg-amd64-disk1-raw.img

9. dd raw image to block device where volume is attached (use dmesg to figure that out easily):

   # dmesg | tail
   [ 7026.943212] virtio-pci 0000:00:05.0: using default PCI settings
   [ 7026.943249] pci 0000:00:07.0: no hotplug settings from platform
   [ 7026.943251] pci 0000:00:07.0: using default PCI settings
   [ 7026.945964] virtio-pci 0000:00:07.0: enabling device (0000 -> 0003)
   [ 7026.955143] virtio-pci 0000:00:07.0: PCI INT A -> Link[LNKC] -> GSI 10 (level, high) -> IRQ 10
   [ 7026.955180] virtio-pci 0000:00:07.0: setting latency timer to 64
   [ 7026.955429] virtio-pci 0000:00:07.0: irq 45 for MSI/MSI-X
   [ 7026.955456] virtio-pci 0000:00:07.0: irq 46 for MSI/MSI-X
   [ 7026.986990] vdb: unknown partition table
   [10447.093426] virtio-pci 0000:00:07.0: PCI INT A disabled
   # dd if=/mnt/precise-server-cloudimg-amd64-disk1-raw.img of=/dev/vdb bs=1M

10. Log out the instance, and use euca-detach-volume to detach the volume:

    $ euca-detach-volume vol-B5863B3B

11. Use euca-create-snapshot to create a snapshot of the volume:

    $ euca-create-snapshot vol-B5863B3B

12. Use euca-register to register the resulting snapshot to create the EBS-backed EMI:

    $ euca-register --name ebs-precise-x86_64-sda \
    --snapshot snap-EFDB40A1 --root-device-name /dev/sda

Thats it!  You have successfully created an EBS-backed EMI/AMI.  As mentioned earlier, these steps can be used on AWS just as well (just skip steps 1 & 2, and use one of the Ubuntu Cloud Images in the AWS region of your choice).  Enjoy!