Matt Gerega

Tag: Application Design

  • Building Software Longevity

    The “Ship of Theseus” thought experiment is an interesting way to start fights with historians, but in software, replacing old parts with new parts is required for building software longevity. Designing software in ways that every piece can be replaced is vital to building software for the future.

    The Question

    The Wikipedia article presents the experiment as follows:

    According to legend, Theseus, the mythical Greek founder-king of Athens, rescued the children of Athens from King Minos after slaying the minotaur and then escaped onto a ship going to Delos. Each year, the Athenians commemorated this legend by taking the ship on a pilgrimage to Delos to honor Apollo. A question was raised by ancient philosophers: After several centuries of maintenance, if each individual part of the Ship of Theseus was replaced, one at a time, was it still the same ship?

    Ship of Theseus – Wikipedia

    The Software Equivalent

    Consider Microsoft Word. Released in 1983, Word is approaching its 40th anniversary. And, while I do not have access into its internal workings, I am willing to bet that most, if not all of the 1983 code has since been replaced by updated modules. So, while it is still called Word, its parts are much newer than the original 1983 iteration. I am sure if I sat here long enough, I could identify other applications with similar histories. The branding does not change, the core functionality does not change, only the code changes.

    Like the wood on the Ship of Theseus, software rots. And it rots fast. Frameworks and languages evolve quickly to take advantage of hardware updates, and the software that uses those must do the same.

    Design for Replacement

    We use the term technical debt to categorize the conscious choices we make to prioritize time to market over perfect code. It is worthwhile to consider software has a “half life” or “depreciation factor” as well: while your code may work today, chances are, without appropriate maintenance, it will rot into something that is no longer able to serve the needs of your customers.

    If I had a “one sized fits all” solution to software rot, I would probably be a millionaire. The truth is, product managers, engineers, and architects must be aware of software rot. Not only must we invest the time into fixing the rot, but we must design our products to allow every piece of the application to be replaced, even as the software still stands.

    This is especially critical in Software as a Service (SaaS) offerings, where we do not have the luxury of large downtimes for upgrades or replacements. To our customers, we should operate continuously, with upgrades happening almost invisibly. This requires the foresight to build replaceable components and the commitment to fixing and replacing components regularly. If you cannot replace components of your software, there will come a day where your software will no longer function for your customers.

  • Designing for the public cloud without breaking the bank

    The ubiquity and convenience of cloud computing resources are a boon to companies who want to deliver digital services quickly. Companies can focus on delivering content to their consumers rather than investing in core competencies such as infrastructure provisioning, application hosting, and service maintenance. However, for those companies who have already made significant investment into these core competencies, is the cloud really better?

    The Push to (Public) Cloud

    The maturation of the Internet and the introduction of public cloud services has reduced the barrier of entry for companies who want to deliver in the digital space. What used to take a dedicated team of systems engineers and a full server/farm buildout can now be accomplished by a few well-trained folks and a cloud account. This allows companies, particularly those in their early growth phases, to focus more on delivering content rather than growing core technological competencies.

    Many companies with heavy investment in core competencies and private clouds are making decisions to move their products to the cloud. This move can offer established companies a chance to “act as a startup” by refining their focus and deliver content faster. However, when those companies look at their cloud bill, there can be an element of sticker shock. [1]

    Why Move

    For a company with a heavy investment in its own private cloud infrastructure, why would you move?

    Inadequate Skillsets for Innovative Technology

    While companies may have significant investments in IT resources, they may not have the capability or desire to train these resources to maintain and manage the latest technologies. For example, managing a production-level Kubernetes cluster requires skills that may not be present in the company today.

    Managed Services

    This is related to the first, but, in many cases, it is much easier to let the company that created the service host it themselves, rather than trying to host it on your own. Things like Elastic or Kafka can be hosted internally, but letting the experts run your instances as a managed service can save you money in the long run.

    Experimentation

    Cloud accounts can provide excellent sand box environments for senior engineers to prove their work quickly, focusing more on functionality than provisioning. Be careful, though, this can lead to skipping the steps between Proof of Concept and Production.

    Building for the future

    As architects/senior engineers, how can we reconcile this? While we want to iterate quickly and focus on delivering customer value, we must also be mindful of our systems’ design.

    Portability

    The folks at Andreessen Horowitz used the term “repatriation” to describe a move back to private clouds from public clouds. As you can imagine, this may be very easy or very difficult, depending on your architecture: repatriating a virtual machine is much easier than, say, repatriating an API Management service from the public cloud to a private offering.

    As engineers design solutions, it is important to think about the portability of the solution you are creating. Can the solution you are building be hosted anywhere (public or private cloud) or is it tailor made to a specific public cloud? The latter may allow for quick ramp up, but will lock you in to a single cloud with little you can do to improve your spend.

    Cost

    When designing a system for the cloud, you must think a lot harder about the pricing of the individual components. Every time you add another service, storage account, VM, or cluster on your design diagram, you are adding to the cost of your system.

    It is important to remember that some of these costs are consumption based, which means you will need to estimate your usage to get a true idea of the cost. I can think of nothing worst than a huge cloud bill on a new system because I forgot to estimate consumption charges

    SOLID Principles

    SOLID design principles are typically applied to object-oriented programming, however, some of those same principles should be applied to larger cloud architectures. In particular, Interface Segregation and Liskov substitution (or, more generally, design by contract) facilitate simpler changes to services by abstracting the implementation from the service definition. Objects that are easier to replace are easier to repatriate into private clouds when profit margins start to shrink.

    What is the Future?

    Do we need the public cloud? Most likely, yes. Initially, it will increase your time to market by removing some of the blockers and allowing your engineers to focus on content rather than core competencies. However, architects and systems engineers need to be aware of the trade offs in going to the cloud. While private clouds represent a large initial investment and monthly maintenance, public cloud costs, particularly those on consumption based pricing, can quickly spiral out of control if not carefully watched.

    If your company already has a good IT infrastructure and the knowledge in place to run their own private clouds, or if your cloud costs are slowly eating into your profit margins, it is probably a good time to consider repatriation of services into private infrastructure.

    As for the future: a mix of public cloud services and private infrastructure services (hybrid cloud) is most likely in my future, however, I believe the trend will be different depending on the maturity and technical competency of your staff.

    References

    1. “Cloud ‘sticker shock’ explored: We’re spending too much”
    2. “The Cost of Cloud, a Trillion Dollar Paradox”