/ ansible

Basic server configuration Ansible

"Ansible is an open-source automation engine that automates software provisioning, configuration management, and application deployment." -Wikipedia

Although Ansible is trying to be simple to use, I bet people will spend time with it's documentation too much. I just made a provision project with Ansible and made a Github repository for it, Ansible wifi router. I have used Ansible before but this was first time I started from the beginning and not just trying to fix problems in other repositories.

Here is little tips and tricks how to get to start.

Best practices

Ansible has a good Best practices page. It is most useful in making a good file architecture. I would suggest to use it even with little automations.

Task snippets

Main usage with Ansible has been installing software with package manager and configure it. Ansible comes with multiple modules for this.

Install software

Use with_items with apt to install multiple software.

- name: Install software with APT package manager
  apt: name={{item}} state=installed
  with_items:
    - hostapd
    - isc-dhcp-server

Comment line in file

Lineinfile is really useful with regular expression. Notice that in this example, if line is not found and commented, line is added to end of the file.

- name: Comment line in dhcpd.conf
  lineinfile:
    dest: /etc/dhcp/dhcpd.conf
    regexp: '^(#?option domain-name )'
    line: '#option domain-name '

Change line value

You can also change line value with lineinfile. Just notice that regular expression must still match the line. In this snippet I have defined only needed beginning of line.

- name: Change line value
  lineinfile:
    dest: /etc/default/isc-dhcp-server
    regexp: '^(#?INTERFACES=")'
    line: 'INTERFACES="{{interface_in}}"'

Insert a template

Easy way to set configuration is templates. Create a template which will replace the configuration file. Templates can also use variables from inventories.

- name: Insert hostapd.conf.j2 template
  template:
    src: templates/hostapd.conf.j2
    dest: /etc/hostapd/hostapd.conf
    owner: root
    group: root
    mode: 0644

Template file hostapd.conf.j2:

ssid={{ssid}}
wpa_passphrase={{passphrase}}

Command

If you do not find an ansible-way to do stuff, just do shell commands with Ansible.

- name: Run command
    command: sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"