README.md

Ansible Role jm1.cloudy.sysctl

This role helps with managing kernel parameters from Ansible variables. For example, it allows to change parameters at runtime with Ansible's [sysctl][ansible-builtin-sysctl] module or edit files in /etc/sysctl.d/ with lineinfile module. Role variable sysctl_config defines a list of tasks which will be run by this role. Each task calls an Ansible module similar to tasks in roles or playbooks except that only few keywords such as when are supported. For example, to enable forwarding of incoming IPv4 packets aka routing, define variable sysctl_config in group_vars or host_vars as such:

sysctl_config:
- # Enable forwarding of IPv4 packets at runtime
  ansible.posix.sysctl:
    name: net.ipv4.ip_forward
    value: '1'
    state: present
    sysctl_file: /etc/sysctl.d/10-ip-forward.conf
    sysctl_set: true
- # Enable forwarding of IPv4 packets after reboots
  ansible.builtin.copy:
    content: |
      # 2021 Jakob Meng, <jakobmeng@web.de>
      net.ipv4.ip_forward = 1
    dest: /etc/sysctl.d/10-ip-forward.conf

When this role is executed, it will run all tasks listed in sysctl_config one after another.

Tested OS images

• Cloud image (amd64) of Debian 10 (Buster)
• Cloud image (amd64) of Debian 11 (Bullseye)
• Cloud image (amd64) of Debian 12 (Bookworm)
• Cloud image (amd64) of Debian 13 (Trixie)
• Cloud image (amd64) of CentOS 7 (Core)
• Cloud image (amd64) of CentOS 8 (Stream)
• Cloud image (amd64) of CentOS 9 (Stream)
• Cloud image (amd64) of Fedora Cloud Base 40
• Cloud image (amd64) of Ubuntu 18.04 LTS (Bionic Beaver)
• Cloud image (amd64) of Ubuntu 20.04 LTS (Focal Fossa)
• Cloud image (amd64) of Ubuntu 22.04 LTS (Jammy Jellyfish)
• Cloud image (amd64) of Ubuntu 24.04 LTS (Noble Numbat)

Available on Ansible Galaxy in Collection jm1.cloudy.

Requirements

This role uses module(s) from collection jm1.ansible. To install this collection you may follow the steps described in README.md using the provided requirements.yml.

Variables

Name	Default value	Required	Description
sysctl_config	[]	false	List of tasks to run 1 2 3, e.g. to update kernel parameters Ansible's [sysctl][ansible-builtin-sysctl] module

Dependencies

None.

Example Playbook

- hosts: all
  become: true
  vars:
    # Variables are listed here for convenience and illustration.
    # In a production setup, variables would be defined e.g. in
    # group_vars and/or host_vars of an Ansible inventory.
    # Ref.:
    # https://docs.ansible.com/ansible/latest/user_guide/playbooks_variables.html
    # https://docs.ansible.com/ansible/latest/user_guide/intro_inventory.html
    sysctl_config:
    - # Enable forwarding of IPv4 packets at runtime
      ansible.posix.sysctl:
        name: net.ipv4.ip_forward
        value: '1'
        state: present
        sysctl_file: /etc/sysctl.d/10-ip-forward.conf
        sysctl_set: true
    - # Enable forwarding of IPv4 packets after reboots
      ansible.builtin.copy:
        content: |
          # 2021 Jakob Meng, <jakobmeng@web.de>
          net.ipv4.ip_forward = 1
        dest: /etc/sysctl.d/10-ip-forward.conf
  roles:
  - name: Manage kernel parameters
    role: jm1.cloudy.sysctl
    tags: ["jm1.cloudy.sysctl"]

For instructions on how to run Ansible playbooks have look at Ansible's Getting Started Guide.

License

GNU General Public License v3.0 or later

See LICENSE.md to see the full text.

Author

Jakob Meng @jm1 (github, galaxy, web)

Footnotes

1. Useful Ansible modules in this context could be blockinfile, copy, file, lineinfile, sysctl and template. ↩

2. Tasks will be executed with jm1.ansible.execute_module which supports keyword when only. ↩

3. Tasks will be executed with jm1.ansible.execute_module which supports modules and action plugins only. Some Ansible modules such as ansible.builtin.meta and ansible.builtin.{include,import}_{playbook,role,tasks} are core features of Ansible, in fact not implemented as modules and thus cannot be called from jm1.ansible.execute_module. Doing so causes Ansible to raise errors such as MODULE FAILURE\nSee stdout/stderr for the exact error. In addition, Ansible does not support free-form parameters for arbitrary modules, so for example, change from - debug: msg="" to - debug: { msg: "" }. ↩