[ec2] Call for testing: Lucid EBS Root Images

[Eric Hammond]

Scott:

When you fix the fstab problem, do you still plan to mount ephemeral0 as
/mnt ?

I lean in this direction to keep the EBS boot AMIs consistent with the
S3 based AMIs.

I still think Amazon made a suboptimal choice in mounting ephemeral
storage directly on /mnt instead of something like /mnt/ephemeral0, but
as I regularly say, "It's often better to be consistent than to be better."

I considered a few cases:

- Users and software may depend on the fact that /mnt has a ton of free
space.

- Users have become accustomed to, and tutorials and software depend on,
/mnt not being bundled when new AMIs are created from a running
instance.  This means that users and software may put private files
there which should not be in the new image.

- Users who read the EC2 documentation (hah!) may wonder and ask where
their 160 GB of "local storage" is if it isn't mounted by default.

Keeping things consistent may make it easier for users to switch from S3
based AMIs to EBS boot AMIs.

There are arguments on the other side including the fact that Amazon
decided to leave the ephemeral storage not mounted on their EBS boot
AMIs.  I think this may have been to reduce confusion for new EC2 users
so that by default the entire local file system is on persistent storage
and will survive through a stop/start cycle.

Flip a coin and then move forward.  The user base will eventually be big
enough that your way will be the right way :)

--
Eric Hammond



Scott Moser wrote:
> Hello all,
>    I've been working on creating EBS root images on ec2 [1].  These are
> being populated with an identical filesystem to our existing UEC images.
> The tools [2] copy the published filesystem images from [3] to a EBS
> volume, snapshot that,  and then register it.
> 
>    I'd love for anyone to give these images a whirl and see what falls on
> the floor.  Without further ado, the following are registered using the
> latest daily lucid build (20100305):
> 
> us-east-1 i386  ami-8bec03e2
> us-east-1 amd64 ami-99ec03f0
> eu-west-1 i386  ami-85b49ff1
> eu-west-1 amd64 ami-87b49ff3
> us-west-1 i386  ami-0971204c
> us-west-1 amd64 ami-15712050
> 
>    Thanks in advance for any testing you can offer.  I've not done much
> more than sniff initial boot, and rely on [4] for the general procedure.
> 
>    I'm aware of one bug in these images that blocks reboot.  Its now fixed
> in cloud-init's trunk and I'll get a package for it soon.  The fix is to
> run the following before reboot:
>    sudo sed -i 's,^ephemeral0,#ephemeral0,' /etc/fstab
> 
> --
> [1] https://blueprints.launchpad.net/ubuntu/+spec/server-lucid-ec2-ebsroot
> [2] https://code.edge.launchpad.net/~ubuntu-on-ec2/ubuntu-on-ec2/ec2-publishing-scripts
> [3] http://uec-images.ubuntu.com/lucid/
> [4] http://alestic.com/2010/01/ec2-ebs-boot-ubuntu
>