GopherCon UK 2018 - Orchestration of microservices
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The document discusses challenges with distributed systems and microservices including communication problems, network errors, message correlation, and consistency issues. It presents strategies for handling failures like retries, idempotent services, and stateful retries. While choreography with peer-to-peer communication is favored in microservices, it can lose sight of the larger workflow and lead to problems. Orchestration with a centralized workflow engine can help address these issues while still allowing services to operate independently. Complex workflows may require a balance of choreography and orchestration.
![The microservice community favours an
alternative approach: smart endpoints and
dumb pipes.
[… Microservices …] are choreographed using
simple RESTish protocols rather than complex
protocols such as WS-Choreography or BPEL or
orchestration by a central tool.
https://www.martinfowler.com/articles/microservices.html](https://image.slidesharecdn.com/orchestrationofmicroservices-180802143513/85/GopherCon-UK-2018-Orchestration-of-microservices-66-320.jpg)
GopherCon UK 2018 - Orchestration of microservices
- 3. Some boring groundwork* * incomplete and inacurate, but useful Blocking Non-blocking sync async
- 4. What is a good place to be? Blocking sync async Non-blocking
- 5. Synchronous communication is the crystal meth of distributed programming Todd Montgomery and Martin Thompson in “How did we end up here” at GOTO Chicago 2015
- 6. What is a good place to be? Blocking sync async Non-blocking
- 7. There will be challenges anyway! Blocking sync async Non-blocking
- 9. Berlin, Germany bernd.ruecker@camunda.com @berndruecker Bernd Ruecker Co-founder and Developer Advocate of Camunda
- 10. Some communication challenges can be solved by state machines aka workflow engines.
- 11. We will do coding with Other tools availabe (e.g. Uber Cadence)
- 12. Photo by pxhere, available under Creative Commons CC0 1.0 license.
- 18. Strategy: Ignore
- 23. Then you get this!
- 26. Requirement: Idempotency of services! Photo by pixabay, available under Creative Commons CC0 1.0 license.
- 27. Requirement: Idempotency of services! Photo by Chr.Späth, available under Public Domain.
- 28. Strategy: Retry Credit Card Payment Charge Credit Card cardNumber amount Charge Credit Card cardNumber Amount transactionId Not idempotent Idempotent
- 31. Persist thing (Entity, Document, Actor, …) State machine or workflow engine DIY = effort and accidental complexity Scheduling, Versioning, operating, visibility, scalability, … Handling State
- 33. Client Zeebe Zeebe Broker Your applicationModel defined here and executed here Workers subscribe (pub/sub) JVM Polyglott, e.g. Go, Java, C#, Node, …
- 35. Client Zeebe Zeebe Broker Your application Streaming / reactive Scale elastically and horizontally Event streaming Peer-to-peer cluster Single Writer Consensus via Raft Model defined here and executed here Workers subscribe
- 36. Workflow automation at scale! low latency, high-throughput low frequency, latency doesn‘t matter What people think workflow automation can do What we currently teach workflow automation to be able to do What workflow automation can already do today
- 38. Zeebes Role Blocking sync async Most often Zeebe is used from services Non-blocking
- 39. Zeebes Role Blocking Non-blocking sync async Some customers envision Zebe as work distribution
- 40. BPMN Business Process Model and Notation ISO Standard
- 41. BPMN Executable and mature Easy to understand* Widespread *(for Biz, Dev, and Ops)
- 43. Zeebe Status Working towards 1.0 end of the year
- 44. But back to concepts
- 47. What if stateful retry gives up? Credit Card Payment REST
- 48. It is impossible to differentiate certain failure scenarios. Independant of communication style! Service Provider Client
- 49. Stateful retry & cleanup Credit Card Payment REST
- 50. Know what‘s going on
- 51. Challenges around message correlation
- 52. Challenge: Timeout handling Credit Card Payment + Incident handling / alarming
- 53. Challenge: Timeout handling Credit Card Payment
- 54. Challenge: Correlation multiple messages
- 55. Challenge: Correlation multiple messages
- 56. Zeebe can buffer messages (if workflow not yet ready)
- 63. Similar when calling multiple services
- 64. Similar when calling multiple services
- 65. Orchestration
- 66. The microservice community favours an alternative approach: smart endpoints and dumb pipes. [… Microservices …] are choreographed using simple RESTish protocols rather than complex protocols such as WS-Choreography or BPEL or orchestration by a central tool. https://www.martinfowler.com/articles/microservices.html
- 70. The danger is that it's very easy to make nicely decoupled systems with event notification, without realizing that you're losing sight of that larger-scale flow, and thus set yourself up for trouble in future years. https://martinfowler.com/articles/201701-event-driven.html
- 71. The danger is that it's very easy to make nicely decoupled systems with event notification, without realizing that you're losing sight of that larger-scale flow, and thus set yourself up for trouble in future years. https://martinfowler.com/articles/201701-event-driven.html
- 72. The danger is that it's very easy to make nicely decoupled systems with event notification, without realizing that you're losing sight of that larger-scale flow, and thus set yourself up for trouble in future years. https://martinfowler.com/articles/201701-event-driven.html
- 73. Microservice pioneers have become aware
- 74. Peer-to-peer communication Checkout Payment Inventory Shipment Fetch the goods before the payment
- 75. Peer-to-peer communication Checkout Payment Inventory Shipment Fetch the goods before the payment
- 76. Order Extract the end-to-end responsibility Checkout Payment Inventory Shipment
- 79. Order Checkout Payment Inventory Shipment Workflow engine itself can run decentralized or centralized
- 80. # Every way of remote communication has challenges # Some challenges require stateful components # Complex peer-to-peer communication can lead to problems, balance choreography and orchestration
- 81. Thank you!