Here’s a tiny plugin to check if a systemd service is running:
#!/bin/bash
#
# машины
#
# Check a if a systemd service is running
#
# Usage: $0
#
#Nagios exit codes
OK=0
WARNING=1
CRITICAL=2
UNKNOWN=3
SERVICE=$1
# Check service status
systemctl -q is-active $SERVICE
if [[ $? -ne 0 ]]; then
echo "ERROR: service $SERVICE is not running"
exit $CRITICAL
fi
echo "OK: service $SERVICE is running"
exit $OK