It is not a trivial task to decompose large monolithic enterprise applications and migrate them into multiple containers architecture without redesign. In this presentation, we dive deeply into the decomposition process and show the ways of making it smooth with the help of auto-scaling and load balancing. Find out the main road blockers and possible solutions during migration of GlassFish based applications from VMs to Containers based on the real experience.

1. From VMs to Containers
Decompose and Migrate
Old Legacy Java EE Applications

2. The Evolution Doesn’t Stay

3. VMs vs Containers on Bare Metal

4. Density and Isolation

5. Elasticity

6. Scalability
Unlike VMs, resizing of resource limits in Containers:
● can be performed without reboot of the running instances
● easier achieved on the fly
● cheaper and faster than moving to larger VMs

7. Efficiency
Virtual Machines Containers on Bare Metal
Container technology unlocks a new level of flexibility – resources that are not consumed within the
limit boundaries are automatically shared with other containers running on the same hardware node.
https://www.infoq.com/articles/java-cloud-cost-reduction

8. Feel the Difference
Resources,RAM
Used Resources vs Scaling Limits

9. Templates Packaging

10. Improved CI/CD

11. Decomposition
Splitting large monolithic application topology into small logical pieces to work with
them independently

12. Can Seem Problematic with Legacy Applications
Picture by Daniel Story

13. But Reachable with the Right Plan and Tools
Tame Your
Legacy Software
Dragon!

14. Let’s See How This Works with GlassFish

15. GlassFish Server in VM

16. Scaling GlassFish Server in VM
● Provision a new VM with preconfigured GlassFish template
● Configure SSH connect and add this VM as an SSH Node to the DAS
● Create a new remote Worker Instance on a Node via DAS UI or asadmin CLI

17. Application Container + System Container
Pros
● IP, hostname and local stored
data survive downtimes
● No need in a port mapping
● Better isolation and virtualization
of resources
● Compatible with SSH based
config tools
● Provide live migration of memory
state
Cons
● Start-up time is slower

18. GlassFish in Container
https://github.com/oracle/docker-images/tree/master/GlassFish/5.0

19. Scaling GlassFish in Containers
Worker nodes can be added / removed automatically as well as can be attached to
DAS node using container orchestration platform and a set of automation scripts

20. Load Balancer
Adding load balancing container in front of our cluster

21. Database Connection
● Connect to the current database in VM
● OR decompose database to containers to gain the benefits of easy scaling
and better resource utilization

22. DEMO

23. Scenario
● Create standalone GlassFish
● Create MySQL master-slave database cluster
● Connect GlassFish to Databases
● Deploy application
● Scale GlassFish and add NGINX load balancer
● Clone the environment
● Install Traffic Distributor and connect it to the two envs (original and clone)

24. Create Standalone GlassFish Server

25. Choose GlassFish and set the limits

26. Creating the environment…

27. Standalone Server > Successfully Created

28. Float Menu > Admin panel > Login

29. Enter credentials

30. Credentials are in your email box

31. Check the nodes

32. Create MySQL Cluster
MySQL Cluster + ProxySQL (PX)

33. Import JPS manifest
https://github.com/jelastic-jps/mysql-cluster/tree/master/mysql-cluster-orchestrator

34. Give a name and press “Install”

35. Your credentials to DB in UI and email box

36. Download test SQL dump
NetBeans Sample App for Connection to MySQL
https://netbeans.org/kb/docs/web/mysql-webapp.html

37. Log in to phpMyAdmin

38. Create a new database

39. Import SQL dump

40. Check the result

41. Set up JDBC connection pool

42. Set up JDBC connection pool

43. DatabaseName=MyNewDatabase
ServerName=[db hostname]
URL=jdbc:mysql://[db hostname]:3306/MyNewDatabase
Url=[same as URL]
User=[db user]
Password=[db password]

44. Check JDBC connection pools

45. Edit JDBC resource

46. Simple Decomposed Topology

47. Download the sample application
Download source and build “war” archive
https://netbeans.org/kb/docs/web/mysql-webapp.html

48. Upload and deploy application

49. Press “Deploy”

50. Float menu > Open in browser

51. Good example of a legacy app 

52. Delve into the depths of your subconscious 

53. Check location of the deployed application

54. Scale the Topology

55. Float menu > Change the topology

56. Add one more GF node (1) and extra resources (2)
1
2

57. Log in to GlassFish admin panel

58. Check the nodes

59. Go to the cluster1 > Check the GMS

60. Check location of the deployed application

61. Clone the Environment and Add Traffic Distributor (TD)

62. Float menu > Clone environment

63. Press “Clone”

64. Environment has been cloned

65. Log in to GF admin panel of the cloned environment

66. Check the nodes

67. Marketplace > Traffic Distributor (TD)

68. Install TD

69. Press “Open in browser”

70. Enjoy Blue-green deployment, HA or A/B testing

72. Get in touch to find out more
@siruslan
@Jelastic