Flink On Yarn模式启动报错：
[root@hadoop01 flink-1.12.0]# bin/yarn-session.sh -n 2 -jm 1024 -tm 1024 -d -s 2
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/yarn/exceptions/YarnException
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
at java.lang.Class.getMethod0(Class.java:3018)
at java.lang.Class.getMethod(Class.java:1784)
at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: org.apache.hadoop.yarn.exceptions.YarnException
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 7 more
顾名思义，提示flink启动缺少Hadoop yarn的相关jar包，从官网下载Flink依赖Hadoop的相关jar包；
https://flink.apache.org/downloads.html
进入官网，下载对应的相关依赖jar包，放到flink lib目录下即可
参考：https://www.jianshu.com/p/90c60bab250e
原文：https://www.cnblogs.com/-courage/p/14800969.html