Microservices are an antipattern

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Microservices are an antipattern Lindsay Holmwood

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Microservices are an antipattern Lindsay Holmwood

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Why microservices?

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Design strategy to manage complexity in our systems

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Design strategy to manage complexity in our systems

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If the system or team get too big, we: 1. Split the system

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If the system or team get too big, we: 1. Split the system

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If the system or team get too big, we: 2. Split the team

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Popularised by the devops movement

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Popularised by the devops movement

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CD + containers were the drivers

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CD + containers were the drivers

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In use at the big end of town

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“It works for Google, so we’ll scale it down and get the same beneﬁts!”

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We cargo culted a design strategy without understanding the tradeoffs

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Real talk: The smallest microservice at Google probably does more transactions than the largest service in your organisation.

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Real talk: We took a pattern for managing huge systems, extrapolated it down to our size, and hoped it worked.

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Real talk: Hope is not a strategy.

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Some downsides you should think about:

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Some downsides you should think about:

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You’re replacing function calls with network calls

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Source: “Systems Performance: Enterprise and the Cloud” by Brendan Gregg

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Is that latency worth it?

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What hard limits are you imposing to control unpredictability?

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Microservices are a systems multiplier for your shitty code

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No content

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How is your ◦ modularity? ◦ isolation? ◦ encapsulation?

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Refactor first

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Then scale when the performance impacts users

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1. Make it work 2. Make it right 3. Make it fast

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1. Make it work 2. Make it right 3. Make it fast Refactor

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1. Make it work 2. Make it right 3. Make it fast Refactor Microservice

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Microservices have a higher cost of ownership

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Operational requirements: ◦ CD pipelines ◦ Network & compute & storage ◦ Logging ◦ Monitoring ◦ Tracing & observability

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Security requirements: ◦ Authentication ◦ Identity ◦ Monitoring

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This costs more (both in systems bills and engineering time)

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But what if we just… didn’t?

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But what if we just… didn’t?

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Problems are harder to debug

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Incidents have > MTTD & MTTR

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Delivery slows

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Increased communication + coordination overhead between teams

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Sequencing of changes across multiple services

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Poor service boundaries? You have to get multiple teams moving in the same direction to deliver a change.

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Stakeholders for technical changes are rarely exclusively technical

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Requires coordination across disciplines like product, design, marketing, analytics, …

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You need established and understood communication paths

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You need established and understood change coordination

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You need established cultural norms for resolving conflict

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Microservices are an effective way to separate concerns in complex systems

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Microservices are an inefficient way of organising people in organisations < 1,000 people