Keynote session from the 2nd event of "Architecture Next 2018"

1. To Microservice
or Not to Microservice?
Eran Stiller
Chief Technology Officer
Azure MVP, MRD
erans@codevalue.net
http://stiller.blog
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2. Agenda
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3. Decomposition
Is this a good design?

4. Decomposition
Is this a good design?

5. Decomposition
Is this a good design?

6. Decomposition
Is this a good design?

7. The Cost of the Software Development Process
number of modules
Module
Integration
cost (complexity)
module
development
Cost (complexity)Cost

8. Microservices Platforms Benefits
Modern microservices platforms significantly reduce the cost of
module integration
Shifting the cost equilibrium towards more modules
Especially true when using proven PaaS platforms
Both public and private cloud based
The integration cost decreases with two factors:
Mature PaaS platform
Proven DevOps process
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9. Monoliths
Why are monoliths considered a bad thing?
They’re not
They all started with good intentions
They usually become convoluted over time
Features are added
People change
Deadlines happen
Technical debt accumulated
It’s very easy to fall
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10. Microservices
Are Microservices the solution?
They also start with good intentions
Will become convoluted with time as well
Without proper architecture and guidance
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11. Monoliths
Natural starting point
Easier to get started and deliver value
Simpler build and deployment
Simpler scalability
Simpler security
Low latency
Intra-process communication
Simpler testing
Simpler logging and monitoring
Simpler data and database
management
Simpler transaction management
Large code base
Simple change requires whole app
to be redeployed
Increased complexity as
functionality is coupled together
Single type of database doesn’t
meet all requirements
Tend to get difficult to work with
over time
Huge resource requirements
Reduced agility over time
Coarse-grain transactions
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Source: https://bit.ly/2vf6eov

12. Microservices
Smaller manageable functional units
Multiple smaller code bases
Single responsibility per service
Single service provides single
functionality
Clearer separation of concerns
Easier on-boarding process
Independently scalable services
Independently deployable
Polyglot technologies & frameworks
as applicable
Frequent functionality releases
Distributed System Architecture
Design, Development, Deployment, CAP
theorem
Handle Increased orchestration
Troubleshooting challenges
Data consistency issues
Eventual consistency
Compensatory & reconciliatory procedures
Increased latency due to remote calls
Distributed Configuration
Management
Organizational Maturity
Architectural complexity
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Source: https://bit.ly/2vf6eov

13. Microservices Drawbacks Solution
Plan ahead
DevOps
Use supporting platforms
Cloud
Containers
Architect
Low Coupling, High Cohesion
Schema/API Versioning
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14. Microservice Architecture
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15. Cohesion
The degree to which a module
performs one and only one function
Strive for high cohesion
A module can be:
Library (assembly, shared module, DLL)
File
Class
Method
COM/CORBA component
(Micro) Service
Any reusable element

16. Coupling
The degree to which each program module
relies on each of the other modules
Low coupling often correlates with
high cohesion, and vice versa
Low coupling is
A sign of a well-structured computer system
Good design
When combined with high cohesion
Supports high readability, maintainability, extendibility, and
reusability
Micro Service Architecture == High Cohesion & Low Coupling

17. Why Should I Care About Coupling
Tightly coupled systems tend to exhibit the following
developmental characteristics
A change in one module usually forces a ripple (cascading) effect
of changes in other modules
Assembly of modules might require more effort and/or time due
to the increased inter-module dependency
A particular module might be harder to reuse and/or test because
dependent modules must be included
The DevOps process becomes a nightmare!!!
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18. How to Decouple Microservices
Have a managed hosting environment
Cloud, Kubernetes, Service Fabric
Use messages (not types)
Use Queues
Or use Service Locators + Load Balancers
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19. So Should I Do Microservices?
YES, but only if you have:
Capable architects
Rapid compute provisioning
Mature CI/CD pipelines
Advanced DevOps culture
OR – get some experts to help 
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Source: https://bit.ly/2oro8Pi

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