[ec2-beta] Can I retrieve the current cost of a running instance?

[Eric Hammond]

Dustin:

The EC2 instance type calculation is a bit more complex than number of 
CPUs.  Both c1.medium($0.20/hr) and m1.large($0.40/hr) have 2 processors.

The accurate instance type for the current instance is available at:

   http://169.254.169.254/latest/meta-data/instance-type/

With the current instance types, you might be able to guess the correct 
one based on the processors, memory, and architecture.  More info:

   http://ec2types.notlong.com

Keep in mind that Amazon will surely be adding more instance types in 
the future.

--
Eric Hammond
ehammond at thinksome.com



Dustin Kirkland wrote:
> On Tue, Feb 3, 2009 at 3:44 PM, Dustin Kirkland <kirkland at ubuntu.com> wrote:
>> Is it possible from a command line within a currently running ec2
>> instance to call out to AWS and retrieve the current cost in dollars
>> of this instance?
>>
>> I suppose it might be roughly calc-able by measuring uptime and
>> network traffic, multiplying by the cost basis, etc.  But that seems
>> really complicated.
> 
> Okay, so I've hacked up a fast-running script (attached) that is
> intended to provide a realistic upper-bound estimated cost of a
> currently running system.
> 
> It computes...
> 
>  * Network charge
>   * Estimate both sent and received network traffic by looking at
> *current* ifconfig statistics
>   * Caveat: this does not account for any no-charge internal traffic
>   * Caveat: it currently lacks logic for the multi-TB price breaks
> (shouldn't be hard to add)
> 
>  * Uptime charge
>   * Estimate your usage charge based on your *current* system uptime
>   * Caveat: It guesses your price bracket based on the number of cpu's
> on the system (is this correct?)
>   * Caveat: I don't have the logic to determine US vs. European prices
> yet (anyone?)
> 
> Finally, all of these are very minor and fast operations on the local
> system (a lot of awk for math, actually), so it runs in like 1/10th of
> a second (which is much faster than any curl call).
> 
> I've browsed the meta-data, but unless I'm missing some good stuff, I
> haven't found much info there that would help me with this.
> 
> In the guests that I've tested, ec2-cost is accurate withing $0.01.
> ec2-cost says $2.51, and Amazon's web interface tells me $2.52.
> 
> Anyone care to run the script and validate/invalidate its accuracy?
> Improvements/contributions would be appreciated.  I am including it as
> part of the screen-profiles package I'm working on, whereby this
> running total could be shown in as a status item at the bottom of
> screen.
> 
> For a screenshot, note the ~$2.51 item in:
>  * http://people.ubuntu.com/~kirkland/Screenshot-ec2-cost.png
> 
> Thanks,
>