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From Jerry Chen <>
Subject Re: [libcloud] pricing update thoughts
Date Thu, 03 Jun 2010 04:39:52 GMT

On Jun 2, 2010, at 11:34 PM, Solomon Hykes wrote:

> On Wed, Jun 2, 2010 at 9:24 PM, Dan Di Spaltro <> wrote:
>> I don't know enough about the DNS protocol, but are there limitations.  This
>> seems like a weird way to do it... Are we just doing it to be novel, or I
>> don't see why a typical webserver serving JSON (pretty well tested) set up
>> isn't good enough.
> The 2 things you get for free with DNS are 1. caching and 2. virtually
> unlimited scalability.
> I would evaluate how much work and money would be spent on
> implementing a cache system in libcloud and hosting a json file
> reliably. Depending on the answer, using DNS will make sense or not.
> Definitely no point in doing it for the sake of novelty.

To add to that, this is how I understand this approach in general:

* Pros for DNS
** Stable
** Existing infrastructure
** Replication/caching is "free"
** Trust/validity (ownership of domain)
** Lends to discovery

* Cons for DNS
** Propagation delay/limitation
** Records have a finite length limitation, e.g. SPF needs indirection
** Different protocol than Provider APIs (DNS v. HTTP)
** Discovery not usually needed, as a lot of other things are already hard-coded, viz. URL
** Non-core library or additional module needed for DNS TXT queries

It definitely would be novel to use DNS, but after writing this all out, perhaps hot potatoes
are still the way to go.
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