1. Deploying Scaleable JVM Apps on
Heroku
Joe Kutner
JVM Languages Owner at Heroku
@codefinger

2. Java
Scala
Groovy
Clojure
JRuby

3. Traditional WAR file deployment…
.war

4. Why WAR?

5. What does modern Java deployment
look like?

6. Modern Java deployment is…
Containerless

7. Modern containerless deployment…

9. Let’s see it in action…

10. java -jar myapp.jar

11. java -jar jetty-runner.jar /my/app/

12. $ heroku deploy:war myapp.war

13. The Twelve Factor App

14. The Twelve Factor App is…
• a manifesto
• a methodology
• a collection of experiences

15. Its goals are…
• scalability
• maintainability
• portability

16. Its does this through…
declarative setup
…explicit dependencies
…external configuration
!
clean contracts
…between your app and its platform
…reduced coupling
!
minimum divergence
…between each deployment
…between dev and prod environments

17. • Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes
Twelve Factors
12factor.net
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes

18. I. Codebase
One codebase, many deploys
Test
Staging
Production

19. I. Codebase
One codebase, many deploys
Test
Staging
Production
$ git push heroku-test master
$ git push heroku-stg master
$ git push heroku-prod master

20. II. Dependencies
Explicitly declared

21. II. Dependencies
Explicitly declared
<dependency>
<groupId>postgresql</groupId>
<artifactId>postgresql</artifactId>
</dependency>

22. II. Dependencies
Explicitly declared
!
libraryDependencies ++= Seq(
"postgresql" % "postgresql" % "9.0-801.jdbc4"
)

23. II. Dependencies
Explicitly declared
<dependency>
<groupId>org.eclipse.jetty</groupId>
<artifactId>jetty-servlet</artifactId>
</dependency>

24. II. Dependencies
Explicitly declared
libraryDependencies ++= Seq(
"com.twitter" % "finagle-http" % "6.18.0",
)

25. III. Configuration
Store config in the environment, not the app

26. III. Configuration
Store config in the environment, not the app
!
<dbUrl>jdbc://postgres...</dbUrl>

27. III. Configuration
Store config in the environment, not the app
URI dbUri = new URI(System.getenv(“DATABASE_URL"));!

28. III. Configuration
Store config in the environment, not the app
$ heroku config:set JAVA_OPTS=“-Xmx512m”

29. IV. Backing Services
Treat backing services as attachable resources

30. IV. Backing Services
Treat backing services as attachable resources

31. IV. Backing Services
Treat backing services as attachable resources
$ heroku addons:add papertrail

32. V. Build, release, run
• A build step vendors dependencies, prepares assets, etc.
• A release step creates a package from build and config.
• A runtime step executes, without special knowledge.

33. V. Build, release, run
$ mvn package

34. V. Build, release, run
$ git push heroku master

35. V. Build, release, run
$ sbt stage deployHeroku

36. VI. Processes
Stateless

37. VI. Processes
Stateless
Don’t write to the local filesystem.

38. VII. Port binding
• Export services via port binding
• Self-contained, not relying on runtime injection by a web server
java -Dserver.port=$PORT -jar …

39. VIII. Concurrency
• Scale out
• Scale up

40. VIII. Concurrency
• Scale out
• Scale up
$ heroku ps:scale web=3

41. VIII. Concurrency
web.2
web.1
worker.3
worker.1 clock.1
Workload Diversity
Number of Processes
worker.2

42. IX. Disposability
Fast startup and graceful shutdown
• Spring Boot and Play do this for you…
• as opposed to big App Servers that take several minutes to boot

43. X. Dev/prod parity
Keep dev, staging, prod and everything in between as similar as possible

44. X. Dev/prod parity
Keep dev, staging, prod and everything in between as similar as possible
dev!
sqlite!
postgres
stage!
mysql!
postgres
prod!
postgres!
postgres
=!
≠!
=
=!
≠!
=

45. XI. Logs
Treat logs as event streams

46. XI. Logs
Treat logs as event streams
DB Web Worker
Event Stream
2014-09-10T22:38:43.427311+00:00 heroku[worker]: ...
2014-09-10T22:38:49.629790+00:00 heroku[web.1]: Starting process...
2014-09-10T22:39:22.056033+00:00 heroku[router]: at=info method=...
2014-09-10T22:38:43.427311+00:00 heroku[postgres]: ...
2014-09-10T22:38:43.427311+00:00 heroku[api]: Release v34 created...
2014-09-10T22:38:49.629790+00:00 heroku[web.1]: Starting process ...
2014-09-10T22:39:22.056033+00:00 heroku[router]: GET mysite.com/ ...

47. XII. Admin Processes
Admin and management tasks should be one-off processes

48. XII. Admin Processes
Admin and management tasks should be one-off processes
web1
web2
web3
admin

49. • Port binding
• Concurrency
• Disposability
• Dev/prod parity
• Logs
• Admin processes
Twelve Factors
• Codebase
• Dependencies
• Config
• Backing services
• Build, release, run
• Processes

50. Further reading…
!
Heroku DevCenter: devcenter.heroku.com
!
Spring Boot Example: https://github.com/kissaten/spring-boot-executable
!
Link to slideshare
!
Twitter: @codefinger

51. Thank You!
Joe Kutner
JVM Languages Owner at Heroku
@codefinger