Docker and Ansible

Introduction

In this article i am going to write ansible playbook that do the following task

Task 1:-

• Installing Docker
• Start and enable Docker services
• Pulling the httpd server image from the Docker Hub
• Run the docker container and expose it to the public

Task 2:-

• Copy the html code in /var/www/html directory
• Starting the web server

Before going any further let me explain you my setup:-

• Red Hat Enterprise Linux(RHEL) 8 as a main OS
• Another RHEL 8 as a target node

Task 1

Step 1:- Configuring YUM Repository

Before install docker in the system our first task is to configuring yum repository so that all the dependency that require to install the docker is satisfied

so now open terminal and type vim docker_ex.yml command to create an file (you can give any name you like but it’s always good to give meaningful name and file extension as yml)

Before proceeding any further ansible use yml(yaml) as a language to create playbook (playbook is a file that content all the task that ansible going to perform on target node)

let write following lines

- hosts: all # its tell ansible to do the task on all ip present in inventory file
  tasks: #list of tasks
    - name: 'Creating directory to mount dvd' # name of the task this is optional you may delete it
      file: #module used to operate on file and folders
        path: '/cdrom' #name of the directory
        state: directory #tell whether its file or folder

save the file and run ansible-playbook docker_ex.yml -v command

We successfully created directory now time to mount the dvd

open docker_ex.yml file and write

    - name: 'Mounting dvd'
      ansible.posix.mount: #module used to perform mount related operation
        path: '/cdrom' # path where we want to mount our dvd
        src: '/dev/cdrom' # name of the device we want to mount
        fstype: 'iso9660' # format type of mount 1so9660 is the most common type of format used in disk
        state: mounted # weather we want to mount or unmount didn't write in quote this is predefine keyword

save the file and run ansible-playbook docker_ex.yml -v command

now dvd is successfully mounted its time create three yum repository 2 form dvd and 1 from following url

https://download.docker.com/linux/centos/7/x86_64/stable/

     - name: 'AppStrem Folder'
       yum_repository: # module used to manage yum repos
         file: 'dvdrepo' # used to specific file name
         name: 'dvd1' # used as unique id for each repo
         baseurl: 'file:///cdrom/AppStream' # path of the repo
         description: 'Appstream' # description of the repo
         gpgcheck: no # disabling gpg check
     - name: 'BaseOS Folder'
       yum_repository:
         file: 'dvdrepo' # used to specific file name
         name: 'dvd2' # used as unique id for each repo
         baseurl: 'file:///cdrom/BaseOS' # path of the repo
         description: 'BaseOS' # description of the repo
         gpgcheck: no # disabling gpg check

    - name: 'Docker Repo'
      yum_repository:
        name: 'dockerrepo' # if file name is missing use as a name of the file
        baseurl: 'https://download.docker.com/linux/centos/7/x86_64/stable' # path of the repo
       description: 'Docker Repo' # description of the repo
         gpgcheck: no # disabling gpg check

save the file and run ansible-playbook docker_ex.yml -v command

now we finally configure yum repository let move to next step

Step 2:- Installing Docker

Now it’s time to install the latest version of docker but there is a problem we can’t directly use package module because redhat didn’t support latest version of docker at the time of writing this file so we have to use command module for this task

   - name: 'Installing docker'
     command: #module used to run command on target node
       cmd: 'yum install docker-ce --nobest -y' # command to execute
       warn: no # sometimes ansible throw waring at the time of running command to this option off that waring 

save the file and run ansible-playbook docker_ex.yml -v command

Image didn’t contain full output because it’s too big to fit in one image

Step 3:- Installing docker api

Before we do further operation on docker we have to install docker api in target node that helps us to ansible to operate on docker this can be download with the help of pip for we need python installed in the system

    - name: 'Installing Python 3'
      package: # module used to install and remove package
        name: 'python3' # name of the package to install
        state: present # predefine keyword used to install package
    
    - name: 'Installing Docker API'
      pip: # used to interact with pip
        name: docker #name of the package to install
        state: present

save the file and run ansible-playbook docker_ex.yml -v command

Image didn’t contain full output because it’s too big to fit in one image

Step 4: Starting docker services

Now it’s time to start docker services or also known as docker engine

    - name: 'Starting Docker engine'
      service: # module used to manage services
        name: 'docker'
        state: started

save the file and run ansible-playbook docker_ex.yml -v command

Step 5:- Installing docker image

Now it’s time to install httpd image from docker hub

    - name: 'Installing image'
      community.general.docker_image: # module used to manage docker image
        name: 'httpd'
        state: present
        source: pull # tell that pull image for registry

save the file and run ansible-playbook docker_ex.yml -v command

now finally its time to start docker conatiner

    - name: 'Starting docker httpd server'
      community.general.docker_container: # module to manage docker container
        name: 'ansible'
        image: 'httpd' # image name form which container is launching
        detach: yes # same as -d
        interactive: no # same -it
        published_ports: '8080:80' #port binding
        container_default_behavior: "no_defaults" # required to tell that didn't use any default options

the above code is same as

docker run -itd --name ansible -p 80:8080 httpd

save the file and run ansible-playbook docker_ex.yml -v command

we can confirm by using target node ip and port number 8080 by curl 192.168.0.107:8080 command

Task 1 is completed

Task 2

Step 1:- Install httpd

Now lets create a new yml file name as httpd_ex.yml and add following lines to install httpd server in target node

- hosts: all
  tasks:
    - package:
        name: 'httpd'
        state: present

save the file and run ansible-playbook httpd_ex.yml -v command

Step 2:- Copy file to target node

First create a html file in current dir name as page.html use vim page.html command to create a file and add the following lines

<h1 style=”color: red”> Hello </h1>

now open httpd_ex.yml and add

   - name: 'Coping File to target node'      
     copy: # module used to copy files and folder to target node    
       src: '/root/ansible_workspace/page.html' # files and folder to copy
       dest: '/var/www/html/' # where to copy

save the file and run ansible-playbook httpd_ex.yml -v command

Step 3:- Starting httpd

Now it’s time to start httpd server in target node

    - name: 'Starting httpd'      
      service:        
        name: 'httpd'        
        state: started

save the file and run ansible-playbook httpd_ex.yml -v command

Step 4:- Firewall

If we try to access our page now we can’t do this due to firewall so let configure port 80 using ansible

    - name: 'Enabling port number'
      ansible.posix.firewalld: #module used to manage firewall ports
        port: 80/tcp #port number that we want to use port/protocol
        state: enabled

save the file and run ansible-playbook httpd_ex.yml -v command

Now go to browser and visit target_node_ip:80/page.html in my case its (http://192.168.0.107/page.html)

Task 2 Completed

Conclusion

Find all the here ➡️ https://github.com/suyash222/ansible_eg

Thank for everyone to reading my article till end if you have any doubt please comment if you have any suggestion please mail all comment both positive and negative is more than welcomed

Contact Detail

LinkeDin [https://www.linkedin.com/in/suyash-garg-50245b1b7]

Additional Tags

#python #vimaldaga #righteducation #educationredefine #rightmentor #worldrecordholder #linuxworld #makingindiafutureready #righeudcation #arthbylw #ansible #docker