machine_setup/ansible/roles/base/tasks/linux.yaml

- name: Set timezone
  file:
    src: "/usr/share/zoneinfo/{{ timezone|default('UTC') }}"
    dest: /etc/localtime
    owner: root
    group: root
    state: link

- name: Install packages
  package:
    name:
      - psmisc
      - pkgfile
      - linux-firmware
      - bind # dig
      - man-db
      - uutils-coreutils
      - usbutils # for lsusb
      - bolt
      - whois
    state: present

- name: Start pkgfile update service
  systemd:
    state: started
    name: pkgfile-update.timer
    daemon_reload: yes
    enabled: yes

- name: Install scripts
  copy:
    src: "files/{{ item.src }}"
    dest: "{{ item.dest }}"
    mode: 0755
    owner: root
    group: wheel
  loop:
    - src: mount_disk_image
      dest: /usr/local/bin/mount_disk_image
    - src: watch_linux
      dest: /usr/local/bin/ww

- name: Configure sysctls
  sysctl:
    name: "{{ item.name }}"
    value: "{{ item.value }}"
    state: present
    sysctl_file: /etc/sysctl.d/{{ item.file }}
  loop:
    # Of questionable value since I don't use swap on my machines
    - name: vm.swappiness
      value: 10
      file: swap.conf
    # Enable TCP packetization-layer PMTUD when an ICMP black hole is detected.
    - name: net.ipv4.tcp_mtu_probing
      value: 1
      file: tcp.conf
    # Switch to bbr tcp congestion control which should be better on lossy connections like bad wifi.
    - name: net.ipv4.tcp_congestion_control
      value: bbr
      file: tcp.conf
    # Don't do a slow start after a connection has been idle for a single RTO.
    - name: net.ipv4.tcp_slow_start_after_idle
      value: 0
      file: tcp.conf
    # 3x time to accumulate filesystem changes before flushing to disk.
    - name: vm.dirty_writeback_centisecs
      value: 1500
      file: power.conf
    # Adjust ttl
    - name: net.ipv4.ip_default_ttl
      value: 65
      file: ttl.conf
    - name: net.ipv6.conf.all.hop_limit
      value: 65
      file: ttl.conf
    - name: net.ipv6.conf.default.hop_limit
      value: 65
      file: ttl.conf