Billing for Clouds

When considering the some of the issues related to building private clouds, the “Usage to Billing” problem was raised and I was reminded of Emlyn Pagden’s Blueprint, “The Utility Model PII” 2003. I had been consulting with a mid sized European Investment Bank, and discussed the architectural problem with them, and Emlyn. Its a while since I have read Emlyn’s paper, but he took the architectural decomposition,

  • Measurement, what are people using
  • Aggregation/Mediation – across the whole estate
  • Allocation – how many charges have they incurred
  • Invoicing – give us our money

and built a reference implementation using Solaris Resource Manager and accounting functionality and some third party products. At the time, he was working for a team that wanted to sell third party software, he had no engineering resources and thus a propensity to use 3rd Party software before building significant scripted functionality. With different resources and motivations, the reference implementation might look quite different, but the paper which was based in a real prototype exposes a working solution. I suspect that not all the companies he mention either still exist, or remain in the “Systems Management” business. However the decomposition should allow easy replacement and the advances in SOA may make this easier to do.

One of the key problems that inhibit adoption of these solutions is that end-user IT departments are cost centres and financially aim to spend or underspend their budgets. Their outgoing charging tariffs are based on cost recovery and they don’t care how busy what they supply is; they have to charge for what they supply. If they don’t do this they make a loss, and the CIO gets fired.

Neither he, nor I experimented with testing this on a grid, and it might involve having a global /etc/projects name space across the whole cloud, but with Virtual Box testing these things becomes easier. Sadly I have picked up enough projects from this trip already, but now I need to build a grid on a laptop.

We both agreed that the invoicing function was best left to the ERP system. Private cloud builders may not need to produce an invoice since they may not be using real money, they will have to make some entries into the Financials systems either cost relief transfers or something. Also new start ups of public clouds may wish to look at Open Bravo, an open source ERP package.


Originally posted on my sun/oracle blog, reposted here in July 2016.

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