sudo tee /etc/systemd/system/rackmon-host-agent.service >/dev/null <<'EOF'
[Unit]
Description=Rackmon host agent
Wants=network-online.target
After=network-online.target

[Service]
Type=simple
User=root
WorkingDirectory=/root
ExecStart=/usr/bin/python3 /root/rackmon_host_agent.py
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload
systemctl enable --now rackmon-host-agent.service
systemctl status rackmon-host-agent.service

sudo tee /Library/LaunchDaemons/com.rackmon.hostagent.plist >/dev/null <<'EOF'
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
 "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>com.rackmon.hostagent</string>

  <key>ProgramArguments</key>
  <array>
    <string>/usr/bin/python3</string>
    <string>/Users/ai/rackmon_host_agent.py</string>
  </array>

  <key>WorkingDirectory</key>
  <string>/Users/ai</string>

  <key>RunAtLoad</key>
  <true/>

  <key>KeepAlive</key>
  <true/>

  <key>StandardOutPath</key>
  <string>/var/log/rackmon_host_agent.log</string>

  <key>StandardErrorPath</key>
  <string>/var/log/rackmon_host_agent.err</string>
</dict>
</plist>
EOF

Fix perms and start

sudo chown root:wheel /Library/LaunchDaemons/com.rackmon.hostagent.plist
sudo chmod 644 /Library/LaunchDaemons/com.rackmon.hostagent.plist

sudo launchctl bootstrap system /Library/LaunchDaemons/com.rackmon.hostagent.plist
sudo launchctl enable system/com.rackmon.hostagent
sudo launchctl kickstart -k system/com.rackmon.hostagent

check status

sudo launchctl print system/com.rackmon.hostagent
tail -f /var/log/rackmon_host_agent.log
tail -f /var/log/rackmon_host_agent.err

To stop/unload

sudo launchctl bootout system /Library/LaunchDaemons/com.rackmon.hostagent.plist