mapreduce出的一些错及解决方案

一、Exception message: CreateSymbolicLink error (1314)

Application Master容器启动时遇到了 CreateSymbolicLink error (1314) 错误。这通常是由于Windows环境下权限不足的问题，特别是符号链接创建时权限受限。

解决方法：打开cmd时右键以管理员身份打开即可

二、Name node is in safe mode.

完整报错信息是：

INFO mapreduce.JobSubmitter: Cleaning up the staging area /tmp/hadoop-yarn/staging/lenovo/.staging/job_1729153942120_0001 Exception in thread "main" org.apache.hadoop.ipc.RemoteException(org.apache.hadoop.hdfs.server.namenode.SafeModeException): Cannot delete /tmp/hadoop-yarn/staging/lenovo/.staging/job_1729153942120_0001. Name node is in safe mode. The reported blocks 5 has reached the threshold 0.9990 of total blocks 5. The number of live datanodes 1 has reached the minimum number 0. In safe mode extension. Safe mode will be turned off automatically in 12 seconds.

解决方法：如高亮所示，安全模式将在12秒后自动退出。你可以稍等一会儿，让 Hadoop 自动退出安全模式后再重试运行你的作业。