Ansible - Basics

This is just a quick sample/demo of the core features it is meant to:

• Show you how ansible works
• Show you what to expect and what can be done

Everything on this page will be covered in more detail in the following sections.

• You will want a user and ssh key on every host but you can also prompt for passwords if needed.
• You can run Ansible from almost anywhere including a laptop.

You will want to start out by creating an inventory file.

Example inventory file:

/etc/ansible/hosts


192.0.3.25
server1.lab.net
server2.lab.net

[group2]
server3.lab.net
server4.lab.net

[webservers]
web1
web2
web3

You can ping all hosts in inventory with this command:

ansible all -m ping

Another test:

ansible all -a "/bin/echo Hello World"
ansible all -a "uname -a"

• NOTE - Spacing and indentation in playbooks is very important.

Basic playbook example:

test-task1.yaml


---
- name: A Test Playbook
  hosts: all
  tasks:
    - name: First Test
      command: "touch /home/user1/testing.txt"

Running a playbook:

ansible-playbook mytask.yaml

Using the ping module and sudo:

ansible all -m ping -u user1 -k             # specify user, ask password
ansible all -m ping -u user1 -k -b -K       # sudo to root

Run shell commands and copy files:

ansible group2 -m ansible.builtin.shell -a 'echo test > output.txt'
ansible group2 -m ansible.builtin.copy -a "src=/etc/hosts dest=/tmp/hosts"

Ensure started, stopped, restarted:

ansible webservers -m ansible.builtin.apt -a "name=nginx update_cache=yes" -b
ansible webservers -m ansible.builtin.apt -a "name=nginx state=absent" -b

ansible webservers -m ansible.builtin.service -a "name=nginx state=started" -b
ansible webservers -m ansible.builtin.service -a "name=nginx state=restarted" -b
ansible webservers -m ansible.builtin.service -a "name=nginx state=stopped" -b

See all facts:

ansible all -m ansible.builtin.setup

Useful Example

Playbook to install an NGINX web server and deploy a web page from a template:

web_deploy.yaml


---
- name: A Test Playbook
  hosts: webservers
  become: yes
  vars:
    var1: "TEST STRING"
  tasks:

    - name: Update repo cache and install nginx package
      ansible.builtin.apt:
        name: nginx
        update_cache: yes

    - name: Make sure a service is started, enabled, and not masked
      ansible.builtin.systemd:
        state: started
        name: nginx
        enabled: true
        masked: no

    - template:
        src: templates/index.html.j2
        dest: /var/www/html/index.html
        mode: a+r

The actual template:

templates/index.html.j2



This is a sample page.
Here is the test value: {{ var1 }}
That is it.

Run the playbook as root on the remote hosts:

ansible-playbook -k -b -K web_deploy.yaml