[FLINK-3517] [dist] Only count active PIDs in start script

This closes apache#1716.

flink-dist/src/main/flink-bin/bin/flink-daemon.sh

@@ -85,8 +85,16 @@ case $STARTSTOP in
 
  # Print a warning if daemons are already running on host
  if [ -f $pid ]; then
- count=$(wc -l $pid | awk '{print $1}')
- echo "[WARNING] $count instance(s) of $DAEMON are already running on $HOSTNAME."
+ active=()
+ while IFS='' read -r p || [[ -n "$p" ]]; do
+ kill -0 $p >/dev/null 2>&1
+ if [ $? -eq 0 ]; then
+ active+=($p)
+ fi
+ done < "${pid}"
+
+ count="${#active[@]}"
+ echo "[INFO] $count instance(s) of $DAEMON are already running on $HOSTNAME."
  fi
 
  echo "Starting $DAEMON daemon on host $HOSTNAME."