maas-devel team mailing list archive

[Robert Collins <robert.collins@xxxxxxxxxxxxx>]

On Fri, Jul 20, 2012 at 9:48 AM, Clint Byrum <clint@xxxxxxxxxx> wrote:
> Excerpts from Gavin Panella's message of 2012-07-19 05:26:38 -0700:
>> On 19 July 2012 10:52, Julian Edwards <julian.edwards@xxxxxxxxxxxxx> wrote:
>> ...
>> >  * Write the entire zone file when adding/updating node groups by generating
>> > hostnames based on IP (like ec2 does).
>>
>> Something I hadn't thought about before: what is the benefit of this
>> over just using IP addresses?
>>
>
> Without this level of indirection, machines will be cemented in one
> place on a network. While MaaS doesn't want a machine to be a special
> snowflake, it doesn't want to require re-deploying everything just to
> change the routing on your network.

!cite - seriously, in a cloud focused approach, I don't see how you
get from A to B. We're anticipating RFC1918 addresses, so public
routable changes should be of little or no consequence. And changes to
RFC1918 space stuff is extremely rare. Add to that that graceful moves
usually involve rotating services to avoid downtime, and my conclusion
is that network renumbering isn't an interesting use case for us.
(Also see again with EC2, the largest and most mature cloud around -
they don't support network renumbering either).

> DNS is still important even when you are the ones controlling the
> addresses. In fact, it should be a lot simpler to get right given that
> position.

Simpler than if we didn't, yes. Simpler than not doing it at all: no.

I think we need to go back to the archetypical users and their needs -
the seed cloud, the production + staging clouds, the hyperscale
clouds, and investigate what jobs they are doing that DNS offers them
value on. I suspect its approximately nothing, particularly as we
scale and memorability diminishes in importance.

-Rob