cannot create /tmp/zookeeper/zookeeper_server.pid

最近使用zookeeper發現, 首次啓動zookeeper時, 都會遇到一個錯誤:

$ bin/zkServer.sh start

JMX enabled by default

Using config: /home/nauhcud/workspace/zookeeper/zookeeper/bin/../conf/zoo.cfg

Starting zookeeper ... bin/zkServer.sh: 162: cannot create /tmp/zookeeper/zookeeper_server.pid: Directory nonexistent

FAILED TO WRITE PID

查看進程發現zookeeper進程存在, 並能夠正常使用. dataDir "/tmp/zookeeper/" 也在. 

kill掉zookeeper進程從新啓動, 一切正常.

刪掉dataDir, 問題依舊.

查看啓動腳本, 發現start邏輯以下:

start)

...

    nohup $JAVA "-Dzookeeper.log.dir=${ZOO_LOG_DIR}" "-Dzookeeper.root.logger=${ZOO_LOG4J_PROP}" \

    -cp "$CLASSPATH" $JVMFLAGS $ZOOMAIN "$ZOOCFG" > "$_ZOO_DAEMON_OUT" 2>&1 < /dev/null &

    if [ $? -eq 0 ] 

    then

      if /bin/echo -n $! > "$ZOOPIDFILE"

      then

        sleep 1

        echo STARTED

      else

        echo FAILED TO WRITE PID   #這句說明寫入Pid出現了問題

        exit 1

      fi  

...

縱觀整個腳本, dataDir沒有出現, 所以, dataDir應該是zookeeper進程內部創建的, 而且有必定延遲, 所以將zookeeper進程id寫入到dataDir下的pidfile時, dataDir尚未創建好, 所以就出現了上述狀況. 

解決辦法很簡單, 在寫入pid以前先判斷一下datadir是否存在, 讓zookeeper有時間作完初始化, 而後再將pid寫入便可.

start)

...

    nohup $JAVA "-Dzookeeper.log.dir=${ZOO_LOG_DIR}" "-Dzookeeper.root.logger=${ZOO_LOG4J_PROP}" \

    -cp "$CLASSPATH" $JVMFLAGS $ZOOMAIN "$ZOOCFG" > "$_ZOO_DAEMON_OUT" 2>&1 < /dev/null &

    zkpid=$!;

    if [ $? -eq 0 ] 

    then

      while [ ! -d `dirname $ZOOPIDFILE` ]

      do  

        sleep 1;

      done

      if /bin/echo -n $zkpid > "$ZOOPIDFILE"

      then

        sleep 1

        echo STARTED

      else

        echo FAILED TO WRITE PID

        exit 1

      fi  

...