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Simple DevOps Project - 4
In this project, we will be see how to use Git, Jenkins, Ansible, DockerHub, Docker to DEPLOY on a docker container.,

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PreRequisites
Jenkins - Get help here
Ansible - Get help here
Setup ansible client and install docker. here
Docker Hub account
Previous DevOps projects:
Simple DevOps project-1 here
Simple DevOps project-2 here
Simple DevOps project-3 here
In part-01 we create Docker image on ansible server through Jenkins job and pushed it onto DockerHub.

Part-01 : Create an docker image
Login to Jenkins console

Create Jenkins job, Fill the following details,

Source Code Management:
Repository : https://github.com/ValaxyTech/hello-world.git
Branches to build : */master
Build:
Root POM:pom.xml
Goals and options : clean install package
Post Steps
Send files or execute commands over SSH

Name: ansible_server
Source files	: webapp/target/*.war
Remove prefix	: webapp/target
Remote directory	: //opt//docker
Send files or execute commands over SSH

Name: ansible_server
Source files	: Dockerfile
Remote directory	: //opt//docker
Exec Command:
cd /opt/docker
docker build -t valaxy_demo .
docker tag valaxy_demo valaxy/valaxy_demo
docker push valaxy/valaxy_demo
docker rmi valaxy_demo valaxy/valaxy_demo
Login to Docker host and check images and containers. (no images and containers)

login to docker hub and check. shouldn't find images with for valaxy_demo

Execute Jenkins job

check images in Docker hub. Now you could able to see new images pushed to Valaxy Docker_Hub

Troubleshooting:
Docker should be installed on ansible server
Should login to "docker hub" on ansible server
ansadmin user should be part of docker group
In Part-02 we create create_docker_container.yml playbook. this get intiated by jenkins job, run by ansible and exected on dokcer_host

Part-02 : Deploy Containers
Write a yml file to create a container (file name : create_docker_container.yml)

  ---
  - hosts: web-servers
    become: true
    tasks:
     - name: stop previous version docker
       shell: docker stop valaxy_demo
     - name: remove stopped container
       shell: docker rm -f valaxy_demo	  
     - name: remove docker images
       shell: docker image rm -f valaxy/valaxy_demo
       
     - name: create docker image
       shell: docker run -d --name valaxy_demo -p 8090:8080 valaxy/valaxy_demo
Add this script to Jenkins job.

Chose "configure" to modify your jenkins job.
Under post build actions
Send files or execute commands over SSH
Exec Command:
   cd /opt/playbooks
   ansible-playbook create_docker_container.yml
Execute Jenkins job.

You could see a new container on your docker host. can able access it from browser on port 8090

Troubleshooting: Makesure you have opened required ports on AWS Security group for this server.

In Part-03 we try to improvise to store docker images previous versions

Part-03 : Deploy with Version Control Containers
So for we used latest docker image to build a container, but what happens if latest version is not working?
One easiest solution is, maintaining version for each build. This can be achieved by using environment variables.

here we use 2 variables

BUILD_ID - The current build id
JOB_NAME - Name of the project of this build. This is the name you gave your job when you first set it up.
for more info Please refer this URL

Lets modify jenkins job which was created in Part-01 as below.

Create Jenkins job
Source Code Management:

Repository : https://github.com/ValaxyTech/hello-world.git
Branches to build : */master
Build:

Root POM:pom.xml
Goals and options : clean install package
Send files or execute commands over SSH

Name: ansible_server
Source files	: webapp/target/*.war
Remove prefix	: webapp/target
Remote directory	: //opt//docker
Send files or execute commands over SSH

Name: ansible_server
Source files	: Dockerfile
Remote directory	: //opt//docker
cd /opt/docker
docker build -t $JOB_NAME:v1.$BUILD_ID .
docker tag $JOB_NAME:v1.$BUILD_ID valaxy/$JOB_NAME:v1.$BUILD_ID
docker tag $JOB_NAME:v1.$BUILD_ID valaxy/$JOB_NAME:latest
docker push valaxy/$JOB_NAME:v1.$BUILD_ID
docker push valaxy/$JOB_NAME:latest
docker rmi $JOB_NAME:v1.$BUILD_ID valaxy/$JOB_NAME:v1.$BUILD_ID
valaxy/$JOB_NAME:latest
References
[1] - Jenkins Docs - Building Software Projects