system_tuning.yml #2

---
# Host-level service and network tuning.
- name: "Exclude p4d and p4broker from automatic restart on package changes"
  ansible.builtin.copy:
    src: "./policy-rc.d"
    dest: "/usr/sbin/policy-rc.d"
    owner: "root"
    group: "root"
    # policy-rc.d must be executable to be honoured by invoke-rc.d.
    mode: '0755'

# The bbr congestion control set below needs the tcp_bbr module. On Debian/Ubuntu
# kernels it is built-in or autoloads; on RedHat-family hosts load and persist it
# explicitly so "sysctl --system" can apply the setting without error.
- name: "Ensure /etc/modules-load.d exists (RedHat)"
  ansible.builtin.file:
    path: "/etc/modules-load.d"
    state: directory
    owner: "root"
    group: "root"
    mode: '0755'
  when: ansible_facts["os_family"] == "RedHat"

- name: "Persist tcp_bbr module across reboots (RedHat)"
  ansible.builtin.copy:
    content: "tcp_bbr\n"
    dest: "/etc/modules-load.d/tcp_bbr.conf"
    owner: "root"
    group: "root"
    mode: '0644'
  when: ansible_facts["os_family"] == "RedHat"

- name: "Load tcp_bbr module (RedHat)"
  community.general.modprobe:
    name: "tcp_bbr"
    state: "present"
  when: ansible_facts["os_family"] == "RedHat"

- name: "Add recommended network tuning to sysctl.d"
  ansible.builtin.blockinfile:
    path: "/etc/sysctl.d/99-perforce.conf"
    create: true
    insertafter: "EOF"
    mode: '0644'
    block: |
      net.ipv4.tcp_congestion_control = bbr
      net.ipv4.tcp_window_scaling = 1
      # allow testing with buffers up to 128MB
      net.core.rmem_max = 62500000
      net.core.wmem_max = 62500000
      # increase Linux autotuning TCP buffer limit to 64MB
      net.ipv4.tcp_rmem = 4096      87380  62500000
      net.ipv4.tcp_wmem = 4096      16384  62500000
      # recommended for hosts with jumbo frames enabled
      net.ipv4.tcp_mtu_probing = 1
      # recommended to enable 'fair queueing'
      net.core.default_qdisc = fq
  notify: "Restart sysctl"