SaltStack state to restart a minion (using the minion you are restarting)

restart_your_minion.sls

---
# salt state file for restarting a minion under its own control

{% set delay = salt['config.get']('minion_restart_in_seconds', 5) %}

restart-the-minion:
  file.managed:
    - name: /tmp/run_command_later.py
    - source: salt://run_command_later.py
    - mode: 775
  cmd.run:
    - require:
      - file: restart-the-minion
    - order: last
    - name: "/tmp/run_command_later.py {{ delay }} systemctl restart salt-minion"
    - bg: true  {# do not wait for completion of this command #}
...

run_command_later.py

#!/usr/bin/env python3
#
# Execute a shell command after a delay time.
#  arg[1] is delay time in seconds
#
import sys, subprocess, time
CHEAP_LOG_FILE = '/tmp/' + __file__ + '.log'

args = sys.argv
if not sys.stdout.isatty():
    sys.stdout = open(CHEAP_LOG_FILE, 'w')  # cheap log output
    sys.stderr = sys.stdout
cmd = args.pop(0)
try:
    delay = float(args.pop(0))
    if not args:  # only an empty list remaining?
        raise ValueError
except (ValueError, IndexError):
    print('Usage: {} seconds_to_delay command and args to run'.format(cmd))
    sys.exit(1)
print('sleeping {} seconds...'.format(delay))
time.sleep(delay)
print(time.asctime())
print('Running command: {}'.format(' '.join(args)))
print('- - - - - - - - - - - - - - -')
sys.stdout.flush()
try:
    subprocess.run(' '.join(args), shell=True, check=True, stdout=sys.stdout, stderr=subprocess.STDOUT)
except subprocess.CalledProcessError as e:
    print(e)

How to tell a remote service to restart itself.

It is a known limitation in SaltStack that in order to update some configuration parameters, you must restart the Salt minion. But -- although you can change those parameters from the Salt master, you cannot then get the minion to read your new configuration because you can't restart it using itself.

This Gist answers that problem by copying as small Python program to the minion which delays for a time, then runs a shell command. That program is then executed using a Salt "cmd.run" state with the "bg: true" option. The Python program then issues a system command to restart the minion.

This version is very simple, and is specific to Linux systems using systemd. Alteration for other systems (like pre 16.04 Ubuntu) is left as an exercise for the reader. Just change the arguments to "run_command_later.py".