Java Colombo 4th Anniversary Meetup Presenters: Lakmal Warusawithana, Imesh Gunaratne

1. Docker for Java Developers
4th Anniversary Java Colombo Meetup
Image Credit: Jordan Novet/VentureBeat

2. Agenda - Session 1
● Introduction to Docker
● Why Docker is Important?
● Let’s Run Docker
● Docker Demo
● Why Need of Docker Cluster?
● Brief Introduction to K8S
● Kubernetes Demo
By Lakmal Warusawithana
Director Cloud Architecture ,WSO2 Inc
Vice President - Apache Stratos
http://twitter.com/lakwarus

3. n
Docker for Java Developers
Session 1

4. n
An Introduction to Docker

5. Virtual Machine vs Container
https://sysadmincasts.com/episodes/31-introduction-to-docker

6. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

7. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

8. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

9. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

10. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

11. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

12. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

13. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

14. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

15. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

16. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

17. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

18. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

19. What is Docker?
https://sysadmincasts.com/episodes/31-introduction-to-docker

20. Docker Image Ecosystem

21. Docker File System

22. n
Why Docker is Important?

23. Why Docker?
● Achieve agility and control for Development and IT Operations
teams to build, ship, and run any app, anywhere
https://www.docker.com

24. Docker Use Cases
https://www.docker.com

25. n
Let's Run Docker

26. How to setup Docker on Linux
● curl -sSL https://get.docker.com/ | sh
● Docker client, the Docker daemon, and
any containers run directly on your
localhost
● Can address ports on a Docker
container using standard localhost
addressing such as localhost:PORT or
Container-IP:PORT

27. How to setup Docker on Mac
● Goto https://docs.docker.
com/engine/installation/mac/
● Docker daemon is running inside a
Linux VM called default
● The default is a lightweight Linux VM
(~24MB download, and boots in
approximately 5s)

28. How to setup Docker on Windows
● Goto https://docs.docker.
com/engine/installation/windows/
● Docker daemon is running inside a
Linux VM called default
● The default is a lightweight Linux VM
(~24MB download, and boots in
approximately 5s)

29. Docker Demo

30. Docker and Windows Containers
● More info :https://www.docker.com/microsoft

31. Docker Compose

32. Why Need of Docker Cluster?
● Avoid single point of failure
● Make horizontally scalable
● Have more granular management for distributed applications
(microservices)
● Self healing systems

33. Why Swarm

34. Docker Swarm

35. n
A Brief Introduction to K8S

36. What is Kubernetes?
● Manage a cluster of Linux containers as a single system to
accelerate Dev and simplify Ops.
● Initiated by Google
● Massive community support

37. Kubernetes Architecture
Node1 Node2 Node n
Physical Network
Master
Overlay Network (Flannel/OpenVSwitch/Weave)APIServer
Scheduler
ControllerManager
etcd

38. Key Concepts of Kubernetes
● Pod - A group of Containers
● Labels - Labels for identifying pods
● Proxy/Service - A load balancer for Pods
● etcd - A metadata service
● cAdvisor - Container Advisor provides resource
usage/performance statistics
● Replication Controller - Manages replication of pods
● Scheduler - Schedules pods in worker nodes
● API Server - Kubernetes API server

39. Kubernetes Pods

40. Kubernetes Pods

41. Kubernetes Labels

42. Kubernetes Labels

43. Kubernetes Replication Controller

44. Kubernetes Replication Controller

45. Kubernetes Services

46. Kubernetes Demo

47. Pet Store Sample
https://github.com/wso2/msf4j/tree/master/samples/petstore/deployment

48. Pet Store Sample - Deployment View
https://github.com/wso2/msf4j/tree/master/samples/petstore/deployment

49. n
Docker for Java Developers
Session 2

50. Agenda - Session 2
● Running a Microservice JAR in a Docker
container
● Building a Docker image with Maven
● Running a Java server application in a
Docker container
● Talking to the Docker API in Java
● Next generation continuous delivery
with Jenkins & Docker
● Deploying Java server applications in
production
Imesh Gunaratne
Senior Technical Lead, WSO2

51. n
Running a Microservice JAR
in a Docker Container

52. Evolution of SOA
http://www.pwc.com/us/en/technology-forecast/2014/cloud-computing/features/microservices.html

53. What is a Microservice?
● “Microservice is an architectural style for developing a single
application as a suite of small services, each running in its
own process and communicating with lightweight mechanisms,
often an HTTP resource API” - Martin Fowler
http://martinfowler.com/articles/microservices.html

54. Monoliths Vs Microservices
http://martinfowler.com/articles/microservices.html

55. Deployment Model
http://martinfowler.com/articles/microservices.html

56. WSO2 MSF4J Hello World Sample
package org.wso2.msf4j.example;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
/**
* Hello service resource class.
*/
@Path("/hello")
public class HelloService {
@GET
@Path("/{name}")
public String hello(@PathParam("name") String name) {
return "Hello " + name;
}
}

57. WSO2 MSF4J Hello World Sample
git clone https://github.com/wso2/msf4j.git
# Build msf4j, this requires JDK 1.8
cd msf4j/
mvn clean install
# Build hello world sample
cd samples/helloworld/
mvn clean install
# Run self contained JAR
java -jar target/helloworld-*.jar
curl http://localhost:8080/hello/java-colombo

58. How to run a Microservice JAR in a
Docker Container
>docker run
# Mount local folder to container
-v ~/dev/wso2/msf4j/samples/helloworld/target/:/tmp/
# Ports to be exposed
-p 8080:8080
# Docker image tag
-t java
# Command to be run
java -jar /tmp/helloworld-1.0.0-SNAPSHOT.jar

59. n
Building a Docker Image
with Maven

60. Docker Maven Plugins
● Spotify Docker Maven Plugin
○ https://github.com/spotify/docker-maven-plugin
● Fabric8io Docker Maven Plugin
○ https://github.com/fabric8io/docker-maven-plugin
● Alex Collins Docker Maven Plugin
○ https://github.com/alexec/docker-maven-plugin
● Wouter Danes Docker Maven Plugin
○ https://github.com/wouterd/docker-maven-plugin

61. Using Spotify Docker Maven Plugin
Add Docker Maven plugin to the pom.xml file:
<build>
<plugins>
<plugin>
<groupId>com.spotify</groupId>
<artifactId>docker-maven-plugin</artifactId>
<version>0.4.0</version>
<configuration>
<imageName>helloworld</imageName>
<baseImage>java</baseImage>
<entryPoint>["java", "-jar", "/${project.build.finalName}.jar"]</entryPoint>
<!-- copy the service's jar file from target into the root directory of the image -->
<resources>
<resource>
<targetPath>/</targetPath>
<directory>${project.build.directory}</directory>
<include>${project.build.finalName}.jar</include>
</resource>
</resources>
</configuration>
</plugin>
</plugins>
</build>

62. Using Spotify Docker Maven Plugin
1. Build Hello World Docker image using Maven:
>mvn clean package docker:build
2. List Docker images:
>docker images
3. Run Hello World Docker container:
>docker run -p 8080:8080 helloworld

63. n
Running a Java Server
Application in a
Docker Container

64. Running Tomcat in Docker
FROM java:8-jre
ENV CATALINA_HOME /usr/local/tomcat
ENV PATH $CATALINA_HOME/bin:$PATH
RUN mkdir -p "$CATALINA_HOME"
WORKDIR $CATALINA_HOME
...
ENV TOMCAT_MAJOR 8
ENV TOMCAT_VERSION 8.0.32
ENV TOMCAT_TGZ_URL https://www.apache.org/dist/tomcat/tomcat-$TOMCAT_MAJOR/v$TOMCAT_VERSION/bin/apache-
tomcat-$TOMCAT_VERSION.tar.gz
RUN set -x
&& curl -fSL "$TOMCAT_TGZ_URL" -o tomcat.tar.gz
&& curl -fSL "$TOMCAT_TGZ_URL.asc" -o tomcat.tar.gz.asc
&& gpg --batch --verify tomcat.tar.gz.asc tomcat.tar.gz
&& tar -xvf tomcat.tar.gz --strip-components=1
&& rm bin/*.bat
&& rm tomcat.tar.gz*
EXPOSE 8080
CMD ["catalina.sh", "run"]

65. Running Tomcat in Docker
● Dockerfile:
○ https://github.com/docker-library/tomcat
● Run Tomcat in Docker container:
○ docker run -it --rm -p 8888:8080 tomcat:8.0

66. n
Talking to the Docker API
in Java

67. Docker API Clients for Java
● Docker Java API
○ https://github.com/docker-java/docker-java
● Docker Client
○ https://github.com/spotify/docker-client
● jClouds Docker API Client
○ https://github.com/jclouds/jclouds-labs/tree/master/docker
● Other API Clients:
● https://docs.docker.com/engine/reference/api/remote_api_client_libraries/

68. Docker Java Client Sample
[docker images cmd]
https://github.com/docker-java/docker-java/wiki
DockerClientConfig config = DockerClientConfig.createDefaultConfigBuilder()
.withDockerHost("tcp://192.168.99.100:2376").build();
DockerClient dockerClient = DockerClientBuilder.getInstance(config).build();
ListImagesCmd cmd = dockerClient.listImagesCmd();
System.out.println("Executing docker images command...");
List<Image> images = cmd.exec();
for(Image image : images) {
System.out.println(new Date(image.getCreated() * 1000) + " - "
+ image.getId() + " - "
+ image.getRepoTags()[0] + " - "
+ image.getVirtualSize());
}

69. Docker Java Client Sample
[docker run cmd]
https://github.com/docker-java/docker-java/wiki
DockerClientConfig config = DockerClientConfig.createDefaultConfigBuilder()
.withDockerHost("tcp://192.168.99.100:2376").build();
DockerClient dockerClient = DockerClientBuilder.getInstance(config).build();
String imageTag = "tomcat:8.0";
System.out.println("Starting container: " + imageTag);
CreateContainerResponse container = dockerClient.createContainerCmd(imageTag).exec();
dockerClient.startContainerCmd(container.getId()).exec();

70. n
Next Generation Continuous
Delivery with
Jenkins & Docker

71. Jenkins Pipeline Plugin
http://devops.com/2016/01/21/12670/
Formerly known as the Workflow plugin. Originally inspired by the Build Flow Plugin.

72. Jenkins Pipeline Plugin UI
https://wiki.jenkins-ci.org/display/JENKINS/Delivery+Pipeline+Plugin

73. Jenkins Pipeline Plugin UI
https://wiki.jenkins-ci.org/display/JENKINS/Delivery+Pipeline+Plugin

74. Jenkins Pipeline works with Docker
http://devops.com/2016/01/21/12670/

75. Jenkins Pipeline Tutorial
https://github.com/jenkinsci/workflow-plugin/blob/master/TUTORIAL.md

76. n
Deploying Java Server
Applications in Production
with Docker

77. Problems with Standalone Docker
● Limited scalability
● Potential risk of Single Point of
Failure (SPOF)

78. Solution -> Docker Cluster

79. Docker Cluster Management Solutions
Kubernetes Docker SwarmApache Mesos

80. Docker Swarm Architecture
https://docs.docker.com/swarm/swarm_at_scale/01-about/

81. Apache Mesos Architecture
https://www.digitalocean.com/community/tutorials/an-introduction-to-mesosphere

82. Kubernetes Architecture
https://mesosphere.com/blog/2015/09/25/kubernetes-and-the-dcos/

83. Deploying Tomcat in Kubernetes [1]
https://github.com/imesh/docker-for-java/tree/master/kubernetes
Node IP: 172.17.8.102
Port: 8080
Domain Name: tomcat
IP: 10.2.10.20
Port: 8080
NodePort: 32001
Protocol: TCP
Pod 1 Pod 2 Pod n
Tomcat Service
L1
L1 L1 L1
Node
Tomcat
Replication
Controller

84. Deploying Tomcat in Kubernetes [2]
https://github.com/imesh/docker-for-java/tree/master/kubernetes
apiVersion: v1
kind: ReplicationController
metadata:
name: tomcat
labels:
name: tomcat
spec:
replicas: 1
selector:
name: tomcat
template:
metadata:
labels:
name: tomcat
spec:
containers:
-
name: tomcat
image: tomcat:8.0
ports:
-
containerPort: 8080
protocol: "TCP"
apiVersion: v1
kind: Service
metadata:
labels:
name: tomcat
name: tomcat
spec:
type: NodePort
sessionAffinity: ClientIP
ports:
# ports that this service should serve on
-
name: 'http'
port: 8080
targetPort: 8080
nodePort: 32001
# label keys and values that must match in
order to receive traffic for this service
selector:
name: tomcat
Tomcat ServiceTomcat Replication
Controller

85. Sample Code
https://github.com/imesh/docker-for-java

86. Thank you!
https://wiki.jenkins-ci.org/display/JENKINS/CloudBees+Docker+Custom+Build+Environment+Plugin