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DevoxxBelgium_StatefulCloud.pptx
- 1. Exploring Stateful Microservices in a Cloud Native World DEVELOPER ADVOCATE, IBM @gracejansen27 GRACE, JANSEN
- 4. The 12 Factor Application • VII. Port binding • Export services via port binding • VIII. Concurrency • Scale out via the process model • IX. Disposability • Maximize robustness with fast startup and graceful shutdown • X. Dev/prod parity • Keep development, staging, and production as similar as possible • XI. Logs • Treat logs as event streams • XII. Admin processes • Run admin/management tasks as one- off processes • I. Codebase • One codebase tracked in revision control, many deploys • II. Dependencies • Explicitly declare and isolate dependencies • III. Config • Store config in the environment • IV. Backing services • Treat backing services as attached resources • V. Build, release, run • Strictly separate build and run stages • VI. Processes • Execute the app as one or more stateless processes
- 5. Cloud-Native == Stateless Microservices
- 6. Cloud-Native == Stateless Microservices
- 8. © 2021 IBM Corporation
- 9. Stateless Computing • State of the data does not get recorded between transactions A communication protocol that does not retain any session information • Scaling the system is easier • Recoverability from system failure is easier Architecture, design and implementation is complex
- 10. Stateful Computing • State of the data gets recorded at every step across all transactions A communication protocol that would retain all session information • Scaling the system is difficult • Recoverability from system failure involves a lot of efforts Architecture, design and implementation is complex
- 11. Realistically , we live in a Stateful world
- 12. “Statefullness” in the cloud- less days
- 13. Client-Server Systems Stateful database systems on the server side Database-styled transactions 2-Phase Commit (2PC) Java Enterprise Java Beans – Stateful EJB (Session vs Entity Beans) Servlet – HTTPSession Client-side caching of server responses Cookie-based authentication Token-based authentication (JWT)
- 14. What do we mean by ‘Transactions’? A transaction is a group of read and write operations that only succeeds if all the operations within it are succesfull. Transactions can impact a single record or multiple records. Holiday Request
- 15. ACID Transactions Atomic Consistent Isolated Durable A C I D All changes to the data must be performed or not at all Data must be in a consistent state before and after the transaction No other process can change the data while the transaction is running The changes made by a transaction must persist
- 16. What are ACID Transactions? • A set of properties of data transactions • Designed to be used as a set of guiding principles • Intended to guarantee data validity • Supports data integrity and security • Utilises consensus protocol • E.g. 2 phase commit (2PC)
- 17. ACID & 2PC Example 2PC Coordinator Holiday Request Flight booking microservice Hotel booking microservice Taxi booking microservice
- 18. ACID transactions & 2PC Issues!!
- 19. 2PC Coordinator Holiday Request Flight booking microservice Hotel booking microservice Taxi booking microservice Communication Failures
- 20. 2PC Coordinator Holiday Request Flight booking microservice Hotel booking microservice Taxi booking microservice Microservice Failures
- 21. Holiday Request Flight booking microservice Hotel booking microservice Taxi booking microservice Coordinator Failure
- 22. Flight booking microservice Hotel booking microservice Taxi booking microservice Coordinator Failure
- 23. Client-Server Systems Stateful database systems on the server side Database-styled transactions 2-Phase Commit (2PC) Java Enterprise Java Beans – Stateful EJB (Session vs Entity Beans) Servlet – HTTPSession Client-side caching of server responses Cookie-based authentication Token-based authentication (JWT)
- 24. Client-Server Systems Stateful database systems on the server side Database-styled transactions 2-Phase Commit (2PC) Java Enterprise Java Beans – Stateful EJB (Session vs Entity Beans) Servlet – HTTPSession Client-side caching of server responses Cookie-based authentication Token-based authentication (JWT)
- 27. Cloud Native Computing: An overarching approach ► “Extension” to Cloud Computing ► Address the ‘true needs’ of enterprise-level distributed business application systems. ► What are the true needs? ► Highly available ► Scalable ► Performant
- 28. The 12 Factor Application • VII. Port binding • Export services via port binding • VIII. Concurrency • Scale out via the process model • IX. Disposability • Maximize robustness with fast startup and graceful shutdown • X. Dev/prod parity • Keep development, staging, and production as similar as possible • XI. Logs • Treat logs as event streams • XII. Admin processes • Run admin/management tasks as one- off processes • I. Codebase • One codebase tracked in revision control, many deploys • II. Dependencies • Explicitly declare and isolate dependencies • III. Config • Store config in the environment • IV. Backing services • Treat backing services as attached resources • V. Build, release, run • Strictly separate build and run stages • VI. Processes • Execute the app as one or more stateless processes
- 29. HOW to preserve state across session, transaction, and network boundaries?
- 30. Techniques / Mechanisms Cache Database-style transactions Cookies Sessions Tokens
- 31. Leader Election (etcd) StatefulSets PersistentVolume Cookie/Session affinity (sticky session) Cloud Native Infrastructure: Containers/Kubernetes This Photo by Unknown Author is licensed under CC BY This Photo by Unknown Author is licensed under CC BY-SA-NC This Photo by Unknown Author is licensed under CC BY-SA This Photo by Unknown Author is licensed under CC BY-SA-NC
- 32. Programming Design Patterns SAGA Long-Running Action / SAGA Interaction Pattern
- 33. SAGA
- 34. What is the SAGA Pattern? • Failure management pattern • Helps to establish consistency in distributed applications • Coordinates transactions between multiple microservices to maintain data consistency • It is a sequence of local transactions where each transaction updates data within a single service
- 35. ACID vs SAGA (BASE) Atomicity Consistency Isolation Durability Basically Available Soft State Eventual Consistency A C I D BA S E
- 36. CAP Theorem SAGA is more aligned with an AP system (eventually consistent)
- 37. Compensating actions Make Payment (T2) Book Seat (T1) Allocate Seat (T3) Start End Unblock Seat Reserve Payment Move Seat back to pool Compensating Transaction
- 38. SAGA Pattern Approach 1 - Choreography
- 39. SAGA Pattern – Approach 1 Microservice 1 Microservice 2 Microservice 3 SAGA SAGA SAGA Each microservices that is part of the transaction publishes an event that is processed by the next microservice
- 40. SAGA Pattern Approach 2 - Orchestration
- 41. SAGA Pattern – Approach 2 Microservice 1 Microservice 2 Microservice 3 SAGA Coordinator SAGA SAGA SAGA SAGA
- 43. 43 What is MicroProfile? ● Eclipse MicroProfile is an open-source community specification for Enterprise Java microservices ● A community of individuals, organizations, and vendors collaborating within an open source (Eclipse) project to bring microservices to the Enterprise Java community microprofile.io
- 46. 46 Open Liberty
- 47. 47 MicroProfile 5.0 Reactive Streams Operators 2.0 Reactive Messaging 2.0 GraphQL 1.1 Context Propagation 1.3 Standalone Projects LRA 1.0 https://developer.ibm.com/components/open-liberty/series/what-is-microprofile/ Jakarta EE JSON-B 2.0 Jakarta EE JSON-P 2.0 Jakatra EE CDI 3.0 Config 3.0 Fault Tolerance 4.0 JWT Propagation 2.0 Health 4.0 Metrics 4.0 Open Tracing 3.0 Open API 3.0 Jakatra EE JAX-RS 3.0 Rest Client 3.0
- 48. Open Liberty and LRA Consists of two parts: 1. LRA participants 2. The LRA coordinator *Beta driver needed
- 49. LRA Coordinator https://openliberty.io/blog/2021/01/27/microprofile-long-running-actions-beta.html
- 50. Single LRA Participant • @LRA • A join/create LRA method that handles any required business logic • @Complete • Used by complete methods, to be called after the LRA completes successfully and handles any required business logic • @Compensate • Used by compensate methods, to be called if the LRA fails for any reason and includes any logic that is required to revert any changes that were made by the join/create method. https://openliberty.io/blog/2021/01/27/microprofile-long-running-actions-beta.html
- 54. Demo Apps
- 55. Open Liberty and LRA https://github.com/yongja79/lr a-blog-example
- 57. Open Liberty session persistence using JCache & Hazelcast Interactive Lab version: https://openliberty.io/guides/sessions.html
- 58. Summary: • Stateful microservices are still needed in this cloud-native world • Traditional mechanisms aren’t always suitable/best for cloud-native • Utilising mechanisms and tools designed and built for the cloud as well as cloud-native infrastructure can enable us to still build effective stateful cloud-native apps • OSS tools and technologies are available to try these out • E.g. MicroProfile LRA, Hazelcast, JCache, etc
- 60. Other Useful Resources • https://openliberty.io/blog/2021/01/27/microprofile-long-running-actions- beta.html • https://github.com/mgrygles/stateful-kube-demo • https://microservices.io/patterns/data/saga.html • https://download.eclipse.org/microprofile/microprofile-lra-1.0- M1/microprofile-lra-spec.html • https://developer.ibm.com/articles/use-saga-to-solve-distributed- transaction-management-problems-in-a-microservices-architecture/
- 61. Links and Materials MicroProfile • MicroProfile Starter: https://start.microprofile.io/ • What is MicroProfile? https://developer.ibm.com/components/open- liberty/series/what-is-microprofile/ • MicroProfile Homepage: https://projects.eclipse.org/proposals/eclipse-microprofile Open Liberty • Open Liberty Starter: https://openliberty.io/start/ • Open Liberty Site: https://openliberty.io/ • Open Liberty Guides: https://openliberty.io/guides • Open Liberty Docs: https://openliberty.io/docs All Open Source! © 2022 IBM Corporation
- 63. Slides