Zero-Downtime Deployment with Kubernetes, SpringBoot & Flyway
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The document discusses zero-downtime deployment using Kubernetes, Flyway, and Spring Boot, emphasizing its importance for company reputation and user expectations. It highlights deployment strategies like blue-green and rolling updates while addressing challenges related to database management and version compatibility. The document also details the integration of Flyway for database migrations within Spring Boot applications to ensure schema compatibility during updates.
Zero-Downtime Deployment with Kubernetes, SpringBoot & Flyway
- 1. @nicolas_frankel ZERO-DOWNTIME DEPLOYMENT With Kubernetes, Flyway and Spring Boot
- 2. @nicolas_frankel Me, myself and I ● Developer Advocate ● Former dev/architect ● DevOps and Cloud curious
- 3. @nicolas_frankel European alternative to the “big” cloud-computing players ● Privacy-minded ● Great support
- 4. @nicolas_frankel Why zero-downtime? 1. Company’s reputation 2. Users’ expectations 3. Missing revenue
- 8. @nicolas_frankel Issues with Blue-Green deployment ● Routing latency ● “Lagging” users ● Database management ○ Migration ○ Or compatibility
- 9. @nicolas_frankel Rolling updates principle 1.0 1.01.02.0 2.0 2.0
- 10. @nicolas_frankel Kubernetes to the rescue! apiVersion: apps/v1 kind: Deployment spec: replicas: 3 strategy: rollingUpdate: maxSurge: 0 maxUnavailable: 1 type: RollingUpdate
- 11. @nicolas_frankel Rolling update options ● maxSurge: ○ Number of extra pods ● maxUnavalaible: ○ Number of down pods allowed
- 12. @nicolas_frankel
- 13. @nicolas_frankel
- 14. @nicolas_frankel
- 15. @nicolas_frankel ● Kubernetes need to know the application’s state ○ To mark the pod ready ● Spring Boot offers the actuator ○ With the /health endpoint Apps don’t start instantly
- 16. @nicolas_frankel Kubernetes-Spring Boot integration magic spec: containers: - name: spring-boot-app image: zerodowntime:1.0 readinessProbe: httpGet: path: /actuator/health port: 8080
- 17. @nicolas_frankel Most talks stop there... ● Let’s pat ourselves on the shoulder ● Hello world apps FTW!
- 18. @nicolas_frankel It’s the database, stupid! 1.0 1.01.02.0 1.02.0
- 19. @nicolas_frankel Version compatibility Consecutive app versions must be schema-compatible
- 20. @nicolas_frankel It’s still the database... 1.0 1.01.02.0 1.0 2.0 2.0 2.0
- 21. @nicolas_frankel Making changes for-/backward compatible Break down a change into a serie of side-by-side compatible changes
- 22. @nicolas_frankel A sample use-case Separating a single table into 2 tables with a Primary Key - Foreign Key relation
- 24. @nicolas_frankel Steps decomposition 1. Create ADDRESS table ○ App use the PERSON table data as previously ○ Trigger copy data to ADDRESS table 2. The ADDRESS becomes the “source of truth” ○ App now uses the ADDRESS table data ○ Trigger copy data to the PERSON table 3. Remove extra columns in the PERSON table
- 25. @nicolas_frankel ● Disable automatic DDL creation/update ● Delegate to Flyway ○ (Or Liquibase) Spring Boot specifics
- 26. @nicolas_frankel Flyway “Version control for your database. Robust schema evolution across all your environments.”
- 27. @nicolas_frankel Flyway 101 ● Based on migrations ● A migration is a SQL script ● Each migration is versioned ● Flyway records migrations in a dedicated table
- 28. @nicolas_frankel Spring Boot Flyway integration ● Migrations are stored in the db/migrations folder ● Automatically applied at application startup
- 29. @nicolas_frankel JPA specifics ● Spring and JPA listeners don’t go along well ● Implementation dependent (Hibernate)
- 31. @nicolas_frankel Thanks! ● https://blog.frankel.ch/ ● @nicolas_frankel ● https://git.io/fhZrq