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Avoid the microservice fallacy put your domain back into the mighty monolith

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Avoid the microservice fallacy put your domain back into the mighty monolith

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Avoid the microservice fallacy put your domain back into the mighty majestic monolith

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Hi, I’m Jakob • Danish immigrant • Father of 3 • Brewer • Rookie surfer • Pragmatist • Curious kind-a-guy • Consultant at Readify • @hgaard • https://blog.hgaard.dk

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Why are we here? • You have a feeling microservices might be a bit hyped and you are curious and want to hear more • You think microservices are awesome and should be used everywhere (and you are here to heckle)

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What are microservices “Service-Oriented Architecture (SOA) is a very broad term and practically meaningless. Microservices is a subset of SOA with the value being that it allows us to put a label on this useful subset of SOA terminology” Martin Fowler

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What are microservices “Microservices is a variant of the service-oriented architecture (SOA) architectural style that structures an application as a collection of loosely coupled services. In a microservices architecture, services should be fine-grained and the protocols should be lightweight” Wikipedia

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Microservice promises • Forces you to improve modularity • Enables parallelized development • Scales on a module level • Improves time to delivery • Makes you get your product to market faster

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All we need to do then is to... “sprinkle a bit of DevOps on top”

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Over-emphasizing benefits • Microservices are distributed computing • Distributed computing is hard • 1st rule of distributed computing

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Fallacies of distributed computing • The network is reliable • Latency is zero • Bandwidth is infinite • The network is secure • Topology doesn't change • There is one administrator • Transport cost is zero • The network is homogeneous

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The microservice premium • Fault tolerance • Dealing with eventual consistency • Multiple deployment pipelines • Elaborate monitoring

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Docker will solve this for us • Yes • It lowers the operational cost of running microservices • But • It does not solve fault tolerance or eventual consistency

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“If you can't build a Monolith, what makes you think you can build distributed microservices” Simon Brown

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• You are not Google, Facebook or Netflix • Don't solve their problems • Chances are that you will never gain the benefits of microservices

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What are you trying to solve? • Scaling vs availability • Breaking system into (the right) components • Independent deployment • Test components independently • It fits your existing organizational silos

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Apply a broader perspective • The DRY obsession • This leads to premature generalization

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“Beware of the Turing tar-pit in which everything is possible but nothing of interest is easy.” Alan Perlis

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We are a hype industry "The hype is driving people to lose focus of what really matters: Customer.” Duncan Bradford

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We are problem solvers

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Put your domain back into the Majestic Monolith

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Monolith or microservice first • Fowler vs Tilkov • Think hard about the costs related to operating a microservice environment • Microservices might enable you to move faster

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The Majestic Monolith • An integrated system that collapses as many unnecessary conceptual models as possible • Encourages the campsite rule • Create a culture that reflects that • Run small teams

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Brown field projects • Safest decision you can make is to solve the business problem first • Your system will never be done • Refactor to Monolith • Once you have a coherent monolith it will be easier to discover its actual components

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Identify what your system is

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Write test on system edges • And refactor like a boss • Understand and appreciate that these tests help specify your domain

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Insist that no service boundary should be left behind • Collapses as many unnecessary conceptual models as possible • Question any attempt of generalization • Rule of 3 • Avoid any internal service boundary like the plague

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Apply all the good principles that are prerequisites for microservices • Apply the discipline required to operate a microservice • Break your domain into well defined components • Mature deployment pipeline • Apply elaborate monitoring

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“Simplicity is prerequisite for reliability.” Edsgar W. Dijkstra

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• Understand that your prime goal is to deliver business value • Microservices are probably more expensive than you think – be sure you want to pay the price • Microservices require a lot of discipline – instead adopt this discipline in your monolith • Know the problem you are solving – don't let potential problems dictate your solution

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So should I use microservices? “It depends…”

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“probably not”