The document discusses microservices architecture. It defines microservices as small, independent services that work together to build applications. The benefits of microservices include rapid development and deployment cycles, independent scalability, and flexibility in programming languages used. Challenges include coordinating transactions across services and managing distributed system complexity. The document also discusses testing microservices through unit, integration, UI, and manual testing. It outlines different approaches to development environments, including fully local or remote options, or routing services between local and cloud.

1. Ali BAKAN
Software Engineer
10.11.2017
ali.bakan@cloudnesil.com
www.cluoudnesil.com
MICRO SERVICES ARCHITECTURE
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2. MICRO SERVICES ARCHITECTURE
AGENDA
1. What are microservices?
2. Reasons for using microservices
3. Challenges
4. Testing microservice based systems
5. Development environments
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3. MICRO SERVICES ARCHITECTURE - WHAT ARE MICROSERVICES?
DEFINITIONS
‣ The microservice architectural style is an approach to
developing a single application as a suite of small services,
each running in its own process and communicating with
lightweight mechanisms, often an HTTP resource API.
‣ These services are built around business capabilities and
independently deployable by fully automated deployment
machinery.
- Martin Fowler
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4. MICRO SERVICES ARCHITECTURE - WHAT ARE MICROSERVICES?
DEFINITIONS
‣ Small autonomous services that work together, modeled
around a business domain.
- Sam Newman, Thoughtworks Inc. (from building
microservices book)
‣ Microservices - also known as the microservice
architecture - is an architectural style that structures an
application as a collection of loosely coupled services,
which implement business capabilities
- Chris Richardson - CloudFoundry
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5. MICRO SERVICES ARCHITECTURE - WHAT ARE MICROSERVICES?
DEFINITIONS
‣ Microservices is a variant of the SOA 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.
It also parallelizes development by enabling small
autonomous teams to develop, deploy and scale services
independently. Microservices-based architectures enable
continuous delivery and deployment
- Wikipedia
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6. MICRO SERVICES ARCHITECTURE - WHAT ARE MICROSERVICES?
CHALLENGES WITH MONOLITHIC SOFTWARE
1. Difficult to scale (Lack of agility)
2. Long build/test/release cycles (Lack of innovation)
3. Long time to add new features (Frustrated customers)
4. Too much software coupling
5. Large Codebase
6. Many Components, no clear ownership
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7. MICRO SERVICES ARCHITECTURE - WHAT ARE MICROSERVICES?
MONOLITHIC VS. MICROSERVICES
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8. MICRO SERVICES ARCHITECTURE - WHAT ARE MICROSERVICES?
MONOLITHIC VS. MICROSERVICES
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9. MICRO SERVICES ARCHITECTURE - REASONS FOR USING MICROSERVICES
WHY SHOULD WE USE?
‣ Rapid build/test/release cycles
‣ Strong modularization ensures that dependencies between
microservices can not easily creep in
‣ Microservices can be easily replaced
‣ The strong modularization and the replaceability of
microservices leads to a sustained speed of development the
architecture remains stable, and micro services that cannot be
maintained any longer can be replaced. Thus, the quality of
the system remains high in the long run, so that the system
stays maintainable
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10. MICRO SERVICES ARCHITECTURE - REASONS FOR USING MICROSERVICES
WHY SHOULD WE USE?
‣ Strong modularization ensures that dependencies
between microservices can not easily creep in
‣ Microservices can be easily replaced
‣ The strong modularization and the replaceability of
microservices leads to a sustained speed of development
the architecture remains stable, and micro services that
cannot be maintained any longer can be replaced. Thus,
the quality of the system remains high in the long run, so
that the system stays maintainable
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11. MICRO SERVICES ARCHITECTURE - REASONS FOR USING MICROSERVICES
WHY SHOULD WE USE?
‣ Legacy systems can be supplemented with microservices
without the need to carry around all the ballast that has
accumulated in the legacy system. Therefore,
microservices are good to use when dealing with legacy
systems.
‣ Microservices can be scaled independently
‣ Each microservice can be implemented in a different
programming language and with a different technology
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12. MICRO SERVICES ARCHITECTURE - REASONS FOR USING MICROSERVICES
WHY SHOULD WE USE?
‣ Smaller Projects
‣ Smaller Teams
‣ Clear ownership and accountability
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13. MICRO SERVICES ARCHITECTURE - CHALLENGES
OR SHOULDN’T WE USE :)
‣ There is no silver bullet in software design!
‣ Understanding of business domain
‣ Coordinating transactions across multiple services
‣ Complexity of testing/deploying/operating a distributed
system
‣ Development environment setup
‣ Log monitoring
‣ Cultural transformation
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14. MICRO SERVICES ARCHITECTURE - TESTING MICROSERVICE BASED SYSTEMS
BASICS
‣ The division of a system into microservices has an impact
on testing
‣ In a microservice-based system the entire system
consisting of all microservices has to be tested
‣ This can be difficult when there are a large number of
microservices
‣ Microservices provide technology freedom; nevertheless,
there have to be certain standards, and tests can help to
enforce the technical standards
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15. MICRO SERVICES ARCHITECTURE - TESTING MICROSERVICE BASED SYSTEMS
UNIT TESTS
‣ Unit tests examine the individual units that compose a
system just as their name suggests
‣ They minimize the risk that an individual unit contain errors
‣ Unit tests are intended to check small units, such as
individual methods or functions
‣ In order to achieve this, any dependencies that exist in the
unit have to replaced so that only the unit under test is
being exercised and not all its dependencies (Mock or
Stub)
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16. MICRO SERVICES ARCHITECTURE - TESTING MICROSERVICE BASED SYSTEMS
INTEGRATION TESTS
‣ Integration tests check the interplay of the components
‣ This is to minimize the risk that the integration of the
components contain errors
‣ They do not use stubs or mocks
‣ The components can be tested as applications via the UI
or via special test frameworks
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17. MICRO SERVICES ARCHITECTURE - TESTING MICROSERVICE BASED SYSTEMS
UI TESTS
‣ UI tests check the application via the user interface
‣ In principle, they only have to test whether the user
interface works correctly
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18. MICRO SERVICES ARCHITECTURE - TESTING MICROSERVICE BASED SYSTEMS
MANUAL TESTS
‣ Check certain aspects like security, performance, or
features that have caused quality problems
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19. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
BASICS
‣ In particular, setting up a productive development
environment for microservices can be considerably more
complex than a traditional web application
‣ Your service might rely on other services that either you or
your coworkers maintain
‣ External dependencies add complexity to creating and
maintaining a development environment
‣ There are various approaches to setting up a development
environment. (from 100% local to 100% remote)
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20. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS 20

21. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
SPIN UP THE FULL SYSTEM LOCALLY
‣ Using tools like Minikube or Docker Compose, you can spin up
multiple services locally
‣ Pros:
- Fast, local development
‣ Cons:
- Need a way to set up and run all your services locally and keep
this setup in sync with how you run services in production
- Need to spin up the whole system locally, which will become
difficult once you have a large enough number of services and
resources
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22. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
SPIN UP THE FULL SYSTEM LOCALLY
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23. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
SPIN UP THE FULL SYSTEM IN THE CLOUD
‣ You spin up a realistic cluster in the cloud, a staging/testing environment
‣ It might not have as many nodes as the production system since load will be much
lower
‣ Pros:
- Very realistic
‣ Cons:
- Development is slower since you need to push code to cloud after every change
in order to try it out
- Using tools like debuggers is more difficult since the code all runs remotely
- Getting log data for development is considerably more complex.
- Need to pay for additional cloud resources
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24. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
SPIN UP THE FULL SYSTEM IN THE CLOUD
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25. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
SPIN UP ALL BUSINESS LOGIC LOCALLY, ROUTE CLOUD SERVICES TO LAPTOP
‣ Spin Up All Business Logic Locally, Route Cloud Services to Laptop
‣ As with option 1, all services run locally. However, cloud resources are made available
locally on your development machine via some sort of tunneling or proxying, e.g., a
VPN
‣ Pros:
‣ Fast, local development
‣ Very realistic.
‣ Cons:
‣ You need a way to set up and run all your services locally and keep this setup in sync
with how you run services in production
‣ Need to pay for additional cloud resources, and spinning up new cloud resources is
slow.
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26. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
SPIN UP ALL BUSINESS LOGIC LOCALLY, ROUTE CLOUD SERVICES TO LAPTOP
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27. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
MAKE LOCAL CODE FOR SINGLE SERVICE AVAILABLE IN REMOTE CLUSTER
‣ You spin up a realistic cluster in the cloud, a staging/testing environment, but
your service runs locally and is proxied/VPNed into the remote cluster
‣ Pros:
- Fast, local development.
- Very realistic.
- Simple local setup
‣ Cons:
- Need to pay for additional cloud resources, and spinning up new cloud
resources is slow
- Configuring a proxy or VPN that works with your cluster can be complex
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28. MICRO SERVICES ARCHITECTURE - DEVELOPMENT ENVIRONMENTS
MAKE LOCAL CODE FOR SINGLE SERVICE AVAILABLE IN REMOTE CLUSTER
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29. MICRO SERVICES ARCHITECTURE
Conway's Law
"Any organization that designs a system will inevitably
produce a design whose structure is a copy of the
organization's communication structure"
Melvin E. Conway, 1967
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30. MICRO SERVICES ARCHITECTURE
SOURCES
‣ https://martinfowler.com/articles/microservices.html
‣ https://en.wikipedia.org/wiki/Microservices
‣ https://dzone.com/articles/development-environments-
for-microservices
‣ https://smartbear.com/blog/test-and-monitor/4-essential-
strategies-for-testing-microservices/
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