Schedule a Left 4 Dead 2 server restart
Left 4 Dead 2 sessions are campaigns, and a restart ends whichever one is in progress. That makes the case for scheduling one weaker here than almost anywhere else.
When should it restart?
Use {{minutes}} where the countdown number should go.
What happens, in order
- Job startsWarn
say Server restarting in 15 min - 10 min beforeWarn
say Server restarting in 10 min - 5 min beforeWarn
say Server restarting in 5 min - 1 min beforeWarn
say Server restarting in 1 min - Restart timeStop
quit
Nothing to save. A restart drops any campaign in progress, so favour a long interval over a short one.
The crontab line
Shifted 15 minutes earlier than your chosen time, so the restart itself lands on it rather than 15 minutes after.
45 3 * * * /opt/restart-l4d2.sh
The script it runs
Save as /opt/restart-l4d2.sh and make it executable. It assumes rcon-cli is on the path and reads the password from the environment rather than embedding it.
#!/usr/bin/env bash
set -euo pipefail
# Scheduled restart for Left 4 Dead 2.
# Generated by spawnly.net/tools/restart-scheduler
# The password stays out of this file. Put it in the environment, or in a
# file only root can read, and export it before this script runs.
RCON_HOST="${RCON_HOST:-127.0.0.1}"
RCON_PORT="${RCON_PORT:-27015}"
: "${RCON_PASSWORD:?set RCON_PASSWORD before running}"
send() {
rcon-cli --host "$RCON_HOST" --port "$RCON_PORT" --password "$RCON_PASSWORD" "$1"
}
# 15 minute warning
send 'say Server restarting in 15 min'
sleep 300
# 10 minute warning
send 'say Server restarting in 10 min'
sleep 300
# 5 minute warning
send 'say Server restarting in 5 min'
sleep 240
# 1 minute warning
send 'say Server restarting in 1 min'
sleep 70
# Shut down cleanly
send 'quit'
# Give the process time to finish writing before anything restarts it.
sleep 30
systemctl start l4d2 2>/dev/null || trueCron uses the server’s timezone, not yours. Check it with timedatectl before assuming 04:00 means 04:00 where you are — a container in UTC and an admin in Europe are two hours apart in summer and one in winter.
The part specific to Left 4 Dead 2
Favour a long interval — weekly rather than daily — and pick an hour when nobody is partway through a campaign. There is nothing to save, so the only cost of a restart is the session it interrupts, and that cost is entirely about timing.