Docker for Java Developers

Docker for Java Developers4th Anniversary Java Colombo Meetup

Image Credit: Jordan Novet/VentureBeat

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 DemoBy Lakmal Warusawithana Director Cloud Architecture ,WSO2 IncVice President - Apache Stratoshttp://twitter.com/lakwarus

n Docker for Java Developers Session 1

n An Introduction to Docker

Virtual Machine vs Container

https://sysadmincasts.com/episodes/31-introduction-to-docker

What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


What is Docker?


Docker Image Ecosystem

Docker File System

n Why Docker is Important?

Why Docker?● Achieve agility and control for Development and IT Operations

teams to build, ship, and run any app, anywhere

https://www.docker.com

Docker Use Cases

https://www.docker.com

n Let's Run Docker

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

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)

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)

Docker Demo

Docker and Windows Containers

● More info :https://www.docker.com/microsoft

Docker Compose

Why Need of Docker Cluster?● Avoid single point of failure

● Make horizontally scalable

● Have more granular management for distributed applications

(microservices)

● Self healing systems

Why Swarm

Docker Swarm

n A Brief Introduction to K8S

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

Kubernetes Architecture

Node1 Node2 Node n

Physical Network

Master

Overlay Network (Flannel/OpenVSwitch/Weave)A

PI S

erve

rSc

hedu

ler

Con

trol

ler M

anag

eret

cd

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

Kubernetes Pods

Kubernetes Pods

Kubernetes Labels

Kubernetes Labels

Kubernetes Replication Controller

Kubernetes Replication Controller

Kubernetes Services

Kubernetes Demo

Pet Store Sample

https://github.com/wso2/msf4j/tree/master/samples/petstore/deployment

Pet Store Sample - Deployment View

https://github.com/wso2/msf4j/tree/master/samples/petstore/deployment

n Docker for Java Developers Session 2

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 GunaratneSenior Technical Lead, WSO2

n

Running a Microservice JAR in a Docker Container

Evolution of SOA

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

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



Monoliths Vs Microservices


Deployment Model


WSO2 MSF4J Hello World Samplepackage 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;

}

}

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

https://github.com/wso2/msf4j.git

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

n

Building a Docker Image with Maven

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

https://github.com/spotify/docker-maven-plugin

https://github.com/spotify/docker-maven-plugin

https://github.com/fabric8io/docker-maven-plugin

https://github.com/fabric8io/docker-maven-plugin

https://github.com/alexec/docker-maven-plugin

https://github.com/alexec/docker-maven-plugin

https://github.com/wouterd/docker-maven-plugin

https://github.com/wouterd/docker-maven-plugin

Using Spotify Docker Maven PluginAdd 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", "/${project.build.finalName}.jar"]</entryPoint>  <resources> <resource> <targetPath>/</targetPath> <directory>${project.build.directory}</directory> <include>${project.build.finalName}.jar</include> </resource> </resources> </configuration> </plugin> </plugins></build>

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

n

Running a Java Server Application in a

Docker Container

Running Tomcat in DockerFROM 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"]

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

https://github.com/docker-library/tomcat

https://github.com/docker-library/tomcat

n

Talking to the Docker API in Java

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/

https://github.com/docker-java/docker-java

https://github.com/docker-java/docker-java

https://github.com/spotify/docker-client

https://github.com/spotify/docker-client

https://github.com/jclouds/jclouds-labs/tree/master/docker

https://github.com/jclouds/jclouds-labs/tree/master/docker

https://docs.docker.com/engine/reference/api/remote_api_client_libraries/

https://docs.docker.com/engine/reference/api/remote_api_client_libraries/

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());}

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();

n

Next Generation Continuous Delivery with

Jenkins & Docker

Jenkins Pipeline Plugin

http://devops.com/2016/01/21/12670/

Formerly known as the Workflow plugin. Originally inspired by the Build Flow Plugin.

Jenkins Pipeline Plugin UI

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

Jenkins Pipeline Plugin UI

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

Jenkins Pipeline works with Docker

http://devops.com/2016/01/21/12670/

Jenkins Pipeline Tutorial

https://github.com/jenkinsci/workflow-plugin/blob/master/TUTORIAL.md

n

Deploying Java Server Applications in Production

with Docker

Problems with Standalone Docker

● Limited scalability● Potential risk of Single Point of

Failure (SPOF)

Solution -> Docker Cluster

Docker Cluster Management Solutions

Kubernetes Docker SwarmApache Mesos

Docker Swarm Architecture

https://docs.docker.com/swarm/swarm_at_scale/01-about/

Apache Mesos Architecture

https://www.digitalocean.com/community/tutorials/an-introduction-to-mesosphere

Kubernetes Architecture

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

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: tomcatIP: 10.2.10.20

Port: 8080NodePort: 32001

Protocol: TCP

Pod 1 Pod 2 Pod n

Tomcat Service

L1

L1 L1 L1

Node

Tomcat Replication Controller

Deploying Tomcat in Kubernetes [2]

https://github.com/imesh/docker-for-java/tree/master/kubernetes

apiVersion: v1kind: ReplicationControllermetadata: name: tomcat labels: name: tomcatspec: replicas: 1 selector: name: tomcat template: metadata: labels: name: tomcat spec: containers: - name: tomcat image: tomcat:8.0 ports: - containerPort: 8080 protocol: "TCP"

apiVersion: v1kind: Servicemetadata: labels: name: tomcat name: tomcatspec: 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

Sample Code

https://github.com/imesh/docker-for-java

Thank you!

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

Software

Docker for Java Developers