diff --git a/prometheusd.sh b/prometheusd.sh
index 47712fc..91e11b1 100755
--- a/prometheusd.sh
+++ b/prometheusd.sh
@@ -2,11 +2,15 @@
 set -e
 
 STATS=${STATS:-/tmp/stats.yaml}
+pid=/tmp/prometheus.pid
 
 case $1 in
   start)
-    rm -f /tmp/prometheus.pid
-    daemonize -c /tmp -p /tmp/prometheus.pid -l /tmp/prometheus.pid -u knot /usr/bin/knot-prometheus-exporter ${STATS}
+    test -f $tmp && echo "prometheus-exporter already running"
+    daemonize -c /tmp -p $tmp -l $tmp -u knot /usr/bin/knot-prometheus-exporter ${STATS}
+    ;;
+  stop)
+    test -f $tmp && cat $tmp | xargs -r kill
+    rm -f $tmp
     ;;
-  stop) cat /tmp/prometheus.pid | xargs -r kill ;;
 esac