[Openstack] Cross-zone instance identifiers in EC2 API - Is it worth the effort?

Soren Hansen soren at linux2go.dk
Fri Jul 8 12:13:06 UTC 2011


2011/7/8 Ewan Mellor <Ewan.Mellor at eu.citrix.com>:
>> From Thorsten von Eicken
>> FYI, there's nothing in the EC2 API that limits instance identifiers
>> (or other IDs) to 32 bits. The IDs are strings, so it's trivial for EC2 to
>> add another digit when running out of 32-bit IDs.
> If that's the case (and I believe you, that's always how I assumed it would be) why don't we just make the EC2 ID be ami-<uuid>?

Vish already explained it in this thread, but the problem is that
while the spec just says it's a string, most clients have much
stricter expectations.

ElasticFox (which Amazon develops themselves) requires e.g. an AMI id
to match ^ami-[0-9a-f]{8}$. I also expect most tools that use a
database store these ID's use a VARCHAR(XXX) (or perhaps even a
CHAR(XXX)). Having a max length at all is wrong according to the spec
(which says it's just a string).

The whole point of supporting the EC2 API is to support people's
existing tools and whatnot. If we follow the spec, but the clients
don't work, we're doing it wrong.


-- 
Soren Hansen        | http://linux2go.dk/
Ubuntu Developer    | http://www.ubuntu.com/
OpenStack Developer | http://www.openstack.org/




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