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Game Server Auto-Start: systemd and Watchdog

Auto-start your game server with systemd, watchdog scripts, restart policies, and tmux/screen usage guide.

Read time: 12 dk Game Server Setup
systemdwatchdogauto-starttmuxscreengame serverrestart
Author
REXE Teknoloji Network & Security Team
Editor
REXE Teknoloji Technical Editorial
First published
Last updated

Introduction

Game servers are services that need to run 24/7. Automatic restart in case of server crashes, system reboots, or unexpected errors is critical. This guide covers systemd service configuration, watchdog scripts, tmux/screen usage, and restart policy settings in detail.

Creating a systemd Service

Basic Service File

hljs bash
sudo nano /etc/systemd/system/gameserver.service
hljs ini
[Unit]
Description=Game Dedicated Server
After=network.target
Wants=network-online.target

[Service]
Type=simple
User=steam
Group=steam
WorkingDirectory=/home/steam/gameserver
ExecStartPre=/home/steam/steamcmd/steamcmd.sh +force_install_dir /home/steam/gameserver +login anonymous +app_update APP_ID +quit
ExecStart=/home/steam/gameserver/start.sh
ExecStop=/bin/kill -SIGINT $MAINPID
Restart=on-failure
RestartSec=30
StartLimitIntervalSec=300
StartLimitBurst=5
TimeoutStartSec=180
TimeoutStopSec=60
StandardOutput=journal
StandardError=journal
SyslogIdentifier=gameserver
LimitNOFILE=100000

[Install]
WantedBy=multi-user.target

Service Management

hljs bash
# Enable service (auto-start on boot)
sudo systemctl daemon-reload
sudo systemctl enable gameserver

# Service management
sudo systemctl start gameserver
sudo systemctl stop gameserver
sudo systemctl restart gameserver
sudo systemctl status gameserver

# View logs
sudo journalctl -u gameserver -f
sudo journalctl -u gameserver --since "1 hour ago"

Restart Policy Settings

Restart Options

OptionDescription
noNo restart
on-successOnly on successful exit
on-failureOn error (exit code != 0)
on-abnormalOn signal or timeout
on-watchdogOn watchdog timeout
alwaysAlways restart

Recommended Configuration

hljs ini
[Service]
Restart=always
RestartSec=15
StartLimitIntervalSec=600
StartLimitBurst=10

This configuration:

  • Server always restarts
  • Waits 15 seconds between restarts
  • Maximum 10 restarts within 600 seconds
  • Service enters failed state if limit exceeded

Resetting Failed Service

hljs bash
sudo systemctl reset-failed gameserver
sudo systemctl start gameserver

Watchdog Script

Simple Watchdog

hljs bash
nano ~/watchdog.sh
hljs bash
#!/bin/bash
SERVICE="gameserver"
LOG="/home/steam/watchdog.log"

while true; do
    if ! systemctl is-active --quiet $SERVICE; then
        echo "$(date): $SERVICE not running, restarting..." >> $LOG
        sudo systemctl restart $SERVICE
        sleep 30
    fi
    sleep 60
done
hljs bash
chmod +x ~/watchdog.sh

Advanced Watchdog (Port Check)

hljs bash
nano ~/watchdog_advanced.sh
hljs bash
#!/bin/bash
SERVICE="gameserver"
PORT=27015
LOG="/home/steam/watchdog.log"
MAX_RETRIES=3
RETRY_COUNT=0

check_port() {
    ss -tuln | grep -q ":$PORT "
    return $?
}

check_process() {
    systemctl is-active --quiet $SERVICE
    return $?
}

while true; do
    if ! check_process; then
        echo "$(date): Process not running, restarting..." >> $LOG
        sudo systemctl restart $SERVICE
        RETRY_COUNT=$((RETRY_COUNT + 1))
        sleep 60
    elif ! check_port; then
        echo "$(date): Port $PORT not responding, checking..." >> $LOG
        RETRY_COUNT=$((RETRY_COUNT + 1))
        if [ $RETRY_COUNT -ge $MAX_RETRIES ]; then
            echo "$(date): $MAX_RETRIES attempts failed, restarting server..." >> $LOG
            sudo systemctl restart $SERVICE
            RETRY_COUNT=0
        fi
        sleep 30
    else
        RETRY_COUNT=0
    fi
    sleep 60
done
hljs bash
chmod +x ~/watchdog_advanced.sh

Running Watchdog with systemd

hljs bash
sudo nano /etc/systemd/system/gameserver-watchdog.service
hljs ini
[Unit]
Description=Game Server Watchdog
After=gameserver.service
Requires=gameserver.service

[Service]
Type=simple
User=steam
ExecStart=/home/steam/watchdog_advanced.sh
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target
hljs bash
sudo systemctl daemon-reload
sudo systemctl enable gameserver-watchdog
sudo systemctl start gameserver-watchdog

Server Management with tmux

tmux Installation

hljs bash
sudo apt install tmux -y

Starting Server with tmux

hljs bash
nano ~/start_tmux.sh
hljs bash
#!/bin/bash
SESSION="gameserver"
tmux kill-session -t $SESSION 2>/dev/null
tmux new-session -d -s $SESSION
tmux send-keys -t $SESSION "cd ~/gameserver && ./start.sh" C-m
echo "Server started in tmux session '$SESSION'."
echo "To attach: tmux attach -t $SESSION"
hljs bash
chmod +x ~/start_tmux.sh

tmux Basic Commands

hljs bash
tmux attach -t gameserver      # Attach to session
# Ctrl+B, then D              # Detach from session
tmux list-sessions             # List sessions
tmux kill-session -t gameserver # Kill session

Server Management with screen

screen Installation

hljs bash
sudo apt install screen -y

Starting Server with screen

hljs bash
nano ~/start_screen.sh
hljs bash
#!/bin/bash
SCREEN_NAME="gameserver"
screen -S $SCREEN_NAME -X quit 2>/dev/null
screen -dmS $SCREEN_NAME bash -c "cd ~/gameserver && ./start.sh"
echo "Server started in screen '$SCREEN_NAME'."
echo "To attach: screen -r $SCREEN_NAME"
hljs bash
chmod +x ~/start_screen.sh

screen Basic Commands

hljs bash
screen -r gameserver           # Attach to screen
# Ctrl+A, then D              # Detach from screen
screen -ls                     # List screens
screen -S gameserver -X quit   # Kill screen

Automatic Update and Restart

hljs bash
nano ~/auto_update_restart.sh
hljs bash
#!/bin/bash
SERVICE="gameserver"
LOG="/home/steam/update.log"
echo "$(date): Starting update..." >> $LOG
sudo systemctl stop $SERVICE
sleep 10
~/steamcmd/steamcmd.sh +force_install_dir ~/gameserver +login anonymous +app_update APP_ID +quit >> $LOG 2>&1
sudo systemctl start $SERVICE
echo "$(date): Update complete." >> $LOG
hljs bash
chmod +x ~/auto_update_restart.sh
crontab -e
0 4 * * * /home/steam/auto_update_restart.sh

Conclusion

With systemd service configuration, watchdog scripts, and tmux/screen usage, you can ensure your game server runs 24/7 without interruption. Proper restart policies and automatic update mechanisms automate server management. REXE VDS reliable infrastructure ensures your server is always accessible.

Frequently Asked Questions

Why is systemd service important?

systemd service ensures your server starts automatically on system boot and restarts on crashes.

What is the difference between tmux and screen?

Both are terminal multiplexers. tmux is more modern and feature-rich, while screen is older and more widespread. Functionally they are similar.

What does a watchdog script do?

A watchdog script regularly checks if the server is running. If the server is down or the port is not responding, it automatically restarts.

How do I configure restart policy?

Configure Restart, RestartSec, StartLimitIntervalSec, and StartLimitBurst parameters in the systemd service file.

How do I view server logs?

Use journalctl -u gameserver -f for live logs and journalctl -u gameserver --since '1 hour ago' for the last hour's logs.

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