18/01/07 02:05:32 INFO ipc.Client: Retrying connect to server: master/192.168.157.10:9000. Already tried 0 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
18/01/07 02:05:33 INFO ipc.Client: Retrying connect to server: master/192.168.157.10:9000. Already tried 1 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
18/01/07 02:05:34 INFO ipc.Client: Retrying connect to server: master/192.168.157.10:9000. Already tried 2 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
18/01/07 02:05:35 INFO ipc.Client: Retrying connect to server: master/192.168.157.10:9000. Already tried 3 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)
18/01/07 02:05:36 INFO ipc.Client: Retrying connect to server: master/192.168.157.10:9000. Already tried 4 time(s); retry policy is RetryUpToMaximumCountWithFixedSleep(maxRetries=10, sleepTime=1 SECONDS)

解决方法：

1、重启hadoop集群

• 进入hadoop的安装目录：cd /usr/local/src/bin
• 关闭所有节点： ./stop-all.sh
• namenode格式化：hadoop namenode-format (注意：选择Y)
• 开启所有的节点：./start-all.sh
  2、防火墙没有关闭
• chkconfig iptables off：防火墙开机不自启动，并不是关闭防火墙
• 清空系统防火墙
  iptables -F
• 保存防火墙配置
  service iptables save
• 临时关闭内核防火墙
  setenforce 0
• 永久关闭内核防火墙
  vim /etc/selinux/config
  SELINUX=disabled