Which Is the Best Way to Make Config Changes in Conf Files in Ansible

Which is the best way to make config changes in conf files in ansible

If it's an INI file, then your specific requirements can be probably met by ini_file module (http://docs.ansible.com/ini_file_module.html).

If your change is limited just few lines (or eve one), then you can probably look at lineinfile module (http://docs.ansible.com/lineinfile_module.html).

Should you however need to change large number of settings, then it may be more beneficial to use template (http://docs.ansible.com/template_module.html) or assemble (http://docs.ansible.com/assemble_module.html). The main disadvantage of this approach is that you may need to review your template or fragments when updating your dependency.

How to edit properly a configuration file of a service and make sure it is loaded in the service with Ansible Playbook?

After several months practicing Ansible, I've got the answer of my interrogation.

It's an Ansible designing purpose habit to take. When I design a new role that aim to set-up a new service, I have two things to do and not forget :

• Flush the handlers though the yaml command


- meta: flush_handlers

- After flush, testing the service is up, for example on a mysql service

- name: Start and enable the service
service:
name: mysql
state: started
enabled: yes
- name: Ensure mysql port is started
wait_for:
port: 3306
delay: 3
timeout: 300


If my configuration is wrong, my handler will be executed before the service execution test (thanks to the flush_handlers), so the service test will fail, and I can fix my mistake.

Rendering a specific Config file Template within Ansible Roles

i suppose you have a link between list of hostnames and file.j2 (same number for example)

    - find:
        path: "path of templates" # give the right folder of templates
        file_type: file
        patterns: '[0-9]+-.*?\.j2'  #search files format xxxx-yyyy.j2
        use_regex: yes
      register: result
  

    - set_fact:
        hosting: "{{ hosting | d([]) + _dico }}"
      loop: "{{ result.files | map(attribute='path') | list }}"
      vars:
        _src: "{{  item }}"
        _num: "{{ (_src | basename).split('-') | first }}"
        _grp: "{{ 'routers' ~ '_' ~ _num }}"
        _hosts: "{{ lookup('vars', _grp)  }}"
        _dico: >-
             {%- set ns = namespace() -%}
             {%- set ns.l = [] -%}
             {%- for h in _hosts -%}
             {%- if h.update({'pathj2': _src}) -%}{%- endif -%}
             {%- set ns.l = ns.l + [h] -%}
             {%-  endfor -%}
             {{ ns.l }}

    - name: Generate configuration files
      template: 
        src: "{{item.pathj2}}"
        dest: ~/ansible/configs/{{item.hostname}}.txt
      loop: "{{ hosting }}"

the first task selects files j2 from folder templates (following the regex pattern)

the second task add the corresponding path of file j2 to the file containing the hostnames

Section aware edits to config files without complicated regex

There is ini_file module.

Example from documentation:

# Ensure "fav=lemonade is in section "[drinks]" in specified file
- ini_file: dest=/etc/conf section=drinks option=fav value=lemonade mode=0600 backup=yes

Ansible modifying files after RPM installation

Your four step procedure looks good to me. Perhaps the service doesn't have to be stopped before modifying the configuration.

I'd create an Ansible role where the necessary tasks are defined. The base structure for the role is created by ansible-galaxy init command.

ansible-galaxy init my_role

The configuration file can be modified (or rather generated) using Ansible's template module:

- name: Modify the configuration file
  template: src=myconf.cnf.j2 dest=/etc/myconf.cnf
  when: "'my_group_name' in group_names"
  notify: Restart the service

It will be run only for the hosts that belong to my_group_name group. Template myconf.cnf.j2 has to be found from my_role/templates directory. The service will be restarted only when Restart the service handler was notified in the task. The handler needs to be put to my_role/handlers/main.yml file:

- name: Restart the service
  service: name=service_name state=restarted

How do you manage per env config file using ansible?

Yes you can. With jinja2 and group_vars.

So what you do in your templates/ folder create a file like such:

templates/http.conf.j2

Say you have something like this in there:

NameVirtualHost *:80

<VirtualHost *:80>
    ServerName {{ subdomain }}.{{ domain }}
    ServerAlias www.{{ subdomain }}.{{ domain }}
</VirtualHost>

Your layout should look like this:

├── group_vars
│   ├── all
│   │   └── config
│   ├── dev
│   │   └── config
│   └── test
│       └── config
├── inventory
│   ├── dev
│   │   └── hosts
│   └── test
│       └── hosts
├── site.yml
└── templates
    └── http.conf.j2

In group_vars/all you would have domain: "example.com"

In group_vars/dev you would have subdomain: dev

In group_vars/test you would have subdomain: test

In your task, you'd have your ansible template command i.e.

- hosts: all
  tasks:
    - name: Copy http conf
        template:
        dest: /etc/apache2/http.conf
        src: templates/http.conf.j2
        owner: root
        group: root

And run your playbook like this:

ansible-playbook -i inventory/test site.yml

The file should end up on the host looking like this:

<VirtualHost *:80>
    ServerName test.example.com
    ServerAlias www.test.example.com
</VirtualHost>

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