DevOps CI/CD pipeline tutorial part 3

I will continue the article DevOps CI/CD pipeline tutorial part 3. In this tutorial, How to integrating Docker in CI/CD pipeline Jenkins.

Jenkins Host –> Docker Host –> Tomcat on Docker container

• DevOps CI/CD pipeline tutorial part 2
• DevOps CI/CD pipeline tutorial part 1

The content is

• Installing Docker on Amazon Linux server
• Integrating Docker with Jenkins
• Deploy a war file on the Docker container using Jenkins.

Installing Docker on Amazon Linux server

Prerequisites

• Amazon Linux EC2 Instance

Installation Docker

[root@Docker_host ~]# yum install docker -y

Check version

[root@Docker_host ~]# docker --version

Start docker services

[root@Docker_host ~]# service docker start
[root@Docker_host ~]# service docker status

Create user admindocker

[root@Docker_host ~]# useradd admindocker
[root@Docker_host ~]# passwd admindocker

Add a user to docker group to manage docker

[root@Docker_host ~]# usermod -aG docker admindocker

Validation

Create a tomcat docker container by pulling a docker image from the public docker registry.

[root@Docker_host ~]# docker run -d --name demo-tomcat-server -p 8090:8080 tomcat:latest

List out running containers

[root@Docker_host ~]# docker ps

Now, we will pull image tomcat from https://hub.docker.com/_/tomcat

You can then go to http://localhost:8080 in a browser (noting that it will return a 404 since there are no webapps loaded by default).

Log in to a docker container

docker exec -it <container_Name> /bin/bash

Default, tomcat container webapp is empty. you access a browser it will return a 404 page. I will copy the example webapps as below:

[root@Docker_host ~]# docker run -d --name tomcat-container -p 8090:8080 tomcat
f2732ff3f29496513c5489863fcc405f243bd07275021074af2107a74713683e
[root@Docker_host ~]# docker ps
CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS                    NAMES
f2732ff3f294        tomcat              "catalina.sh run"   7 seconds ago       Up 6 seconds        0.0.0.0:8090->8080/tcp   tomcat-container
[root@Docker_host ~]# docker exec -it f2732ff3f294 /bin/bash
root@f2732ff3f294:/usr/local/tomcat# ll
bash: ll: command not found
root@f2732ff3f294:/usr/local/tomcat# ls
BUILDING.txt     LICENSE  README.md      RUNNING.txt  conf     lib   native-jni-lib  webapps       work
CONTRIBUTING.md  NOTICE   RELEASE-NOTES  bin          include  logs  temp            webapps.dist
root@f2732ff3f294:/usr/local/tomcat# cp -R webapps.dist/* webapps/

Integrating Docker with Jenkins

Login to console Jenkins

Add ” Publish Over SSH ” plugin.

Manage Jenkins > Configure System >  Publish over SSH

You need to allow Password Authentication of SSH on Docker Host server ( if you use password)

[root@Docker_host ~]# grep PasswordAuthentication /etc/ssh/sshd_config
PasswordAuthentication yes

For example, Jenkins copy artifacts to Docker host

Add post-build action –> Send build artifacts over SSH

Result,

Deploy a war file on the Docker container using Jenkins.

Create Dockerfile to copy the war file to the delivery folder.

Example Dockerfile simple

FROM tomcat:latest
COPY ./HelloWorld.war /usr/local/tomcat/webapps

Jenkins setting copy war to the docker container.

Link Youtube

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