Ansible

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Basic Installing and Configuring NTP with Ansible

I have been learning from this book Fabio Alessandro Locati, published under Packt>.

There is one simple exercise where there is an example of “Ensuring that NTP is installed, configured and running”. The codes can be found at https://github.com/PacktPublishing/Learning-Ansible-2.X-Third-Edition/tree/master/Chapter02

--- 
- hosts: all 
  remote_user: ansible
  tasks: 
    - name: Ensure NTP is installed 
      yum: 
        name: ntp 
        state: present 
      become: True 
    - name: Ensure the timezone is set to UTC 
      file: 
        src: /usr/share/zoneinfo/GMT 
        dest: /etc/localtime 
        state: link 
      become: True 
    - name: Ensure the NTP service is running and enabled 
      service: 
        name: ntpd 
        state: started 
        enabled: True 
      become: True
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Basic Installing and Configuring a Web Server with Ansible

I have been learning from this book Fabio Alessandro Locati, published under Packt>

There is one simple exercise where there is an example of “Installing and Configuring a Web Server”. The codes can be found at https://github.com/PacktPublishing/Learning-Ansible-2.X-Third-Edition/tree/master/Chapter02

Installing and Configuring a Web Server

The first set of codes deal with the installation and enabling of HTTPd package and services. In addition, both HTTP and HTPS must be able to pass through the firewalld

-- 
- hosts: all 
  remote_user: ansible
  tasks: 
    - name: Ensure the HTTPd package is installed 
      yum: 
        name: httpd 
        state: present 
      become: True 
    - name: Ensure the HTTPd service is enabled and running 
      service: 
        name: httpd 
        state: started 
        enabled: True 
      become: True 
    - name: Ensure HTTP can pass the firewall 
      firewalld: 
        service: http 
        state: enabled 
        permanent: True 
        immediate: True 
      become: True 
    - name: Ensure HTTPS can pass the firewall 
      firewalld: 
        service: https 
        state: enabled 
        permanent: True 
        immediate: True 
      become: True

Reviewing and Running the Deployment, we can use the command to fire it. 

$ ansible-playbook webserver.yaml --list-tasks
$ ansible-playbook -i host webserver.yaml

Publishing a Simple Website

Assuming the Website is a simple single-page website using a simple template call index.html.j2

--- 
- hosts: all 
  remote_user: ansible
  tasks: 
    - name: Ensure the website is present and updated 
      template: 
        src: index.html.j2 
        dest: /var/www/html/index.html 
        owner: root 
        group: root 
        mode: 0644 
      become: True

Just a note that the “become: True” parameter represents the fact that the tasks should be executed with sudo access. In other words, the sudo user’s file should allow access

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Basic Ansible Introductory Learning Notes

I have been learning from this book Fabio Alessandro Locati, published under Packt>

I thought I just capture a few learning notes as I read.

Introduction to Playbooks

Playgroups are one of the core features of Ansible and tell what Ansible what to execute. They are like a do-list for Ansible that contains a list of tasks; each task internally links to a piece of code called a module

- hosts: all 
  remote_user: vagrant
  tasks: 
    - name: Ensure the HTTPd package is installed 
      yum: 
        name: httpd 
        state: present 
      become: True 
    - name: Ensure the HTTPd service is enabled and running 
      service: 
        name: httpd 
        state: started 
        enabled: True 
      become: True

What it means?

  • hosts: List the Host or Host groups. The Host field is required. The –list-hosts-host will let us know which hosts the playbook is using.
  • remote_user: The user Ansible will be using while logging onto the system.
  • There are 2 tasks.
    • The first one is to ensure that the httpd package is present
    • The 2nd one is to enable the httpd service is enabled and running
  • The tasks are quite self-explanatory.
  • become: True. The commands should be executed with sudo access. If the sudo user’s file does not allow the user to run the particular command, the command will fail

Running a Playbook

$ ansible-playbook -i host setup_apache.yml

Ansible Verbosity

You can increase the verbosity by using the parameter -v, -vv or -vvv

Variables in Ansible

---
- hosts: all
  remote_user: vagrant
  tasks: 
    - name: Print OS and version
      debug:
        msg: '{{ ansible_distribution }} {{ ansible_distribution_version }}'

Creating the Ansible User

--- 
- hosts: all 
  user: vagrant 
  tasks: 
    - name: Ensure ansible user exists 
      user: 
        name: ansible 
        state: present 
        comment: Ansible 
      become: True
    - name: Ensure ansible user accepts the SSH key 
      authorized_key: 
        user: ansible 
        key: https://github.com/fale.keys 
        state: present 
      become: True
    - name: Ensure the ansible user is sudoer with no password required 
      lineinfile: 
        dest: /etc/sudoers 
        state: present 
        regexp: '^ansible ALL\=' 
        line: 'ansible ALL=(ALL) NOPASSWD:ALL' 
        validate: 'visudo -cf %s'
      become: True

The lineinfile is an interesting module. It works in a similar way to sed (a stream editor) where you specify the regular expression that will be used to match the line, and then specify the new line that will be used to substitute the matched line.