Master Ansible Playbooks: Deploy Webpages and Automate Server Patching

What are Playbooks and How to Write Them?

• A playbook is a configuration file where scripts are written.

• It is a straightforward YAML file that looks like this:

Let's consider a simple example to print the date. Create a file named show_date.yml.

-
  name: Date playbook
  hosts: servers
  tasks:
    - name: Show date
      command: date

A playbook always begins with a “-”.

Lets run this playbook:

ansible-playbook show_date.yml

• The output will appear as follows:

• To check the output run below command:

ansible-playbook -v show_date.yml

• Using a playbook file, you can perform various checks on servers.

mv show_date.yml show_server_stats.yml

show_server_stats.yml

-
  name: Date playbook
  hosts: servers
  tasks:
    - name: Show date
      command: date
    - name: Show RAM
      command: free -h
    - name: Show DISK
      command: df -h
    - name: Show uptime
      command: uptime

• Run the playbook:

ansible-playbook -v show_server_stats.yml

Install docker on multiple servers:

• Let's create a script to install Docker “install_docker.yml“ on three different machines from the master server.

-
  name: Install Docker
  hosts: servers
  become: yes
  tasks:
    - name: install docker based on server distribution
      apt:            #apt built_module of ansible. Refer document and search apt in it, you will get the code.
        name: docker.io
        state: latest
      when: ansible_distribution == 'Debian' or ansible_distribution == 'Ubuntu'

    - name: install the latest version of docker based on distribution
      dnf:
        name: docker
        state: latest
      when: ansible_distribution == 'Amazon' or ansible_distribution == 'RedHat'

Here’s a simple explanation of the provided Ansible playbook:

1. - name: Install Docker
   This is the name of the playbook, describing its purpose (to install Docker).

2. hosts: servers
   Specifies that the playbook will run on the hosts group named "servers."

3. become: yes
   Enables privilege escalation (sudo) to perform tasks as a superuser.

4. tasks:
   Declares the list of tasks to be executed in this playbook.

5. - name: install docker based on server distribution
   Names the first task, which installs Docker on Debian or Ubuntu systems.

6. apt:
   Uses the apt module to manage packages on Debian-based distributions.

7. name: docker.io
   Specifies that the package to be installed is docker.io.

8. state: latest
   Ensures the latest version of Docker is installed.

9. when: ansible_distribution == 'Debian' or ansible_distribution == 'Ubuntu'
   Runs this task only if the server's operating system is Debian or Ubuntu.

10. - name: install the latest version of docker based on distribution
    Names the second task, which installs Docker on Amazon Linux or Red Hat systems.

11. dnf:
    Uses the dnf module to manage packages on Red Hat-based distributions.

12. name: docker
    Specifies that the package to be installed is docker.

13. state: latest
    Ensures the latest version of Docker is installed.

14. when: ansible_distribution == 'Amazon' or ansible_distribution == 'RedHat'
    Runs this task only if the server's operating system is Amazon Linux or Red Hat.

• You can refer to the Ansible Module documentation to write any ansible code.

• To list the available details for ansible_distribution on the system, execute the following command:

ansible servers -m setup | grep "ansible_distribution"

• Now we will run below command to install docker

ansible-playbook -v install_docker.yml

---

Deploy Webpage with Ansible on Multiple Servers

To deploy a project using Ansible, follow these steps:

First, visit my GitHub repository. You have the option to fork the repository or copy the code for index.html.

Then, create a file named deploy_webpage.yml to facilitate the deployment of the webpage.

-
  name: Deploy Webpage to nginx/apache
  become: yes
  hosts: servers
  tasks:
    - name: install nginx/apache
      apt:
        name: nginx
        state: latest
      when: ansible_distribution == 'Ubuntu'

    - name: start nginx/apache
      service:
        name: nginx
        enabled: yes
      when: ansible_distribution == 'Ubuntu'

    - name: copy webpage to server destination
      copy:
        src: index.html
        dest: /var/www/html
      when: ansible_distribution == 'Ubuntu'

To view the webpage on server1, execute the deploy_webpage.yml file.

ansible-playbook -v deploy_webpage.yml

To view the deployed webpage, obtain the public IP address of server1 of Ubuntu from AWS. Then, enter the following URL in your browser: http://public_ip_server1.

You will now see that our webpage has been successfully deployed.

Similarly we can deploy Webpage on other two servers Amazon Linux 2 and RedHat.

Add below code into deploy_webpage.yml file:

-
  name: Deploy Webpage to nginx/apache
  become: yes
  hosts: servers
  tasks:
    - name: install nginx/apache
      apt:
        name: nginx
        state: latest
      when: ansible_distribution == 'Ubuntu'

    - name: start nginx/apache
      service:
        name: nginx
        enabled: yes
      when: ansible_distribution == 'Ubuntu'

    - name: install nginx/apache
      dnf:
        name: httpd
        state: latest
      when: ansible_distribution == 'Amazon' or ansible_distribution == 'Redhat'

    - name: start nginx/apache
      service:
        name: httpd
        state: started
        enabled: yes
      when: ansible_distribution == 'Amazon' or ansible_distribution == 'Redhat'

    - name: copy webpage to server destination
      copy:
        src: index.html
        dest: /var/www/html

Now, copy the public IP addresses of the Amazon and RedHat servers. You will be able to see that your webpage has been successfully deployed.

---

Server Patching Playbook

Refer this documentation for update_cache:

To create a server patching playbook, begin by creating a file named: patch_servers.yml.

-
 name: Apply Patching Activity
 hosts: servers
 become: yes
 tasks:
   - name: Upgrade the servers
     apt:
       update_cache: yes
       upgrade: dist
     when: ansible_distribution == 'Ubuntu'

   - name: Upgrade the RHEL CentOS Packages
     dnf:
       name: "*"
       state: latest
     when: ansible_distribution in ['Amazon', 'Redhat']

   - name: Reboot the servers
     reboot:
       msg: "Rebooting servers: Patching activity in progress"
       reboot_timeout: 600

To execute this script, follow these steps:

ansible-playbook -v patch_servers.yml

This guide explains how to patch your servers using an Ansible Playbook.