报错背景：
CDH集成sqoop2服务之后，创建好link和job之后，执行job的时候报错。
报错现象：
sqoop:000> start job -j 1 Exception has occurred during processing command Exception: org.apache.sqoop.common.SqoopException Message: CLIENT_0001:Server has returned exception - <html><head><title>Apache Tomcat/6.0.53 - Error report</title><style><!--H1 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:22px;} H2 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:16px;} H3 {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;font-size:14px;} BODY {font-family:Tahoma,Arial,sans-serif;color:black;background-color:white;} B {font-family:Tahoma,Arial,sans-serif;color:white;background-color:#525D76;} P {font-family:Tahoma,Arial,sans-serif;background:white;color:black;font-size:12px;}A {color : black;}A.name {color : black;}HR {color : #525D76;}--></style> </head><body><h1>HTTP Status 500 - Servlet execution threw an exception</h1><HR size="1" noshade="noshade"><p><b>type</b> Exception report</p><p><b>message</b> <u>Servlet execution threw an exception</u></p><p><b>description</b> <u>The server encountered an internal error that prevented it from fulfilling this request.</u></p><p><b>exception</b> <pre>javax.servlet.ServletException: Servlet execution threw an exception org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:631) org.apache.hadoop.security.token.delegation.web.DelegationTokenAuthenticationFilter.doFilter(DelegationTokenAuthenticationFilter.java:301) org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:579) </pre></p><p><b>root cause</b> <pre>java.lang.NoClassDefFoundError: org/codehaus/jackson/map/JsonMappingException org.apache.hadoop.mapreduce.Job.getJobSubmitter(Job.java:1291) org.apache.hadoop.mapreduce.Job.submit(Job.java:1302) org.apache.sqoop.submission.mapreduce.MapreduceSubmissionEngine.submitToCluster(MapreduceSubmissionEngine.java:274) org.apache.sqoop.submission.mapreduce.MapreduceSubmissionEngine.submit(MapreduceSubmissionEngine.java:255) org.apache.sqoop.driver.JobManager.start(JobManager.java:288) org.apache.sqoop.handler.JobRequestHandler.startJob(JobRequestHandler.java:380) org.apache.sqoop.handler.JobRequestHandler.handleEvent(JobRequestHandler.java:116) org.apache.sqoop.server.v1.JobServlet.handlePutRequest(JobServlet.java:96) org.apache.sqoop.server.SqoopProtocolServlet.doPut(SqoopProtocolServlet.java:79) javax.servlet.http.HttpServlet.service(HttpServlet.java:646) javax.servlet.http.HttpServlet.service(HttpServlet.java:723) org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:631) org.apache.hadoop.security.token.delegation.web.DelegationTokenAuthenticationFilter.doFilter(DelegationTokenAuthenticationFilter.java:301) org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:579) </pre></p><p><b>root cause</b> <pre>java.lang.ClassNotFoundException: org.codehaus.jackson.map.JsonMappingException java.net.URLClassLoader.findClass(URLClassLoader.java:382) java.lang.ClassLoader.loadClass(ClassLoader.java:424) java.lang.ClassLoader.loadClass(ClassLoader.java:357) org.apache.hadoop.mapreduce.Job.getJobSubmitter(Job.java:1291) org.apache.hadoop.mapreduce.Job.submit(Job.java:1302) org.apache.sqoop.submission.mapreduce.MapreduceSubmissionEngine.submitToCluster(MapreduceSubmissionEngine.java:274) org.apache.sqoop.submission.mapreduce.MapreduceSubmissionEngine.submit(MapreduceSubmissionEngine.java:255) org.apache.sqoop.driver.JobManager.start(JobManager.java:288) org.apache.sqoop.handler.JobRequestHandler.startJob(JobRequestHandler.java:380) org.apache.sqoop.handler.JobRequestHandler.handleEvent(JobRequestHandler.java:116) org.apache.sqoop.server.v1.JobServlet.handlePutRequest(JobServlet.java:96) org.apache.sqoop.server.SqoopProtocolServlet.doPut(SqoopProtocolServlet.java:79) javax.servlet.http.HttpServlet.service(HttpServlet.java:646) javax.servlet.http.HttpServlet.service(HttpServlet.java:723) org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:631) org.apache.hadoop.security.token.delegation.web.DelegationTokenAuthenticationFilter.doFilter(DelegationTokenAuthenticationFilter.java:301) org.apache.hadoop.security.authentication.server.AuthenticationFilter.doFilter(AuthenticationFilter.java:579) </pre></p><p><b>note</b> <u>The full stack trace of the root cause is available in the Apache Tomcat/6.0.53 logs.</u></p><HR size="1" noshade="noshade"><h3>Apache Tomcat/6.0.53</h3></body></html> Stack trace: at org.apache.sqoop.client.request.ResourceRequest (ResourceRequest.java:140) at org.apache.sqoop.client.request.ResourceRequest (ResourceRequest.java:179) at org.apache.sqoop.client.request.JobResourceRequest (JobResourceRequest.java:112) at org.apache.sqoop.client.request.SqoopResourceRequests (SqoopResourceRequests.java:154) at org.apache.sqoop.client.SqoopClient (SqoopClient.java:460) at org.apache.sqoop.shell.StartJobFunction (StartJobFunction.java:80) at org.apache.sqoop.shell.SqoopFunction (SqoopFunction.java:51) at org.apache.sqoop.shell.SqoopCommand (SqoopCommand.java:127) at org.apache.sqoop.shell.SqoopCommand (SqoopCommand.java:103) at org.codehaus.groovy.tools.shell.Command$execute (null:-1) at org.codehaus.groovy.tools.shell.Shell (Shell.groovy:101) at org.codehaus.groovy.tools.shell.Groovysh (Groovysh.groovy:-1) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:-2) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl (DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method (Method.java:498) at org.codehaus.groovy.reflection.CachedMethod (CachedMethod.java:90) at groovy.lang.MetaMethod (MetaMethod.java:233) at groovy.lang.MetaClassImpl (MetaClassImpl.java:1054) at org.codehaus.groovy.runtime.ScriptBytecodeAdapter (ScriptBytecodeAdapter.java:128) at org.codehaus.groovy.tools.shell.Groovysh (Groovysh.groovy:173) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:-2) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl (DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method (Method.java:498) at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSiteNoUnwrapNoCoerce (PogoMetaMethodSite.java:267) at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite (PogoMetaMethodSite.java:52) at org.codehaus.groovy.runtime.callsite.AbstractCallSite (AbstractCallSite.java:141) at org.codehaus.groovy.tools.shell.Groovysh (Groovysh.groovy:121) at org.codehaus.groovy.tools.shell.Shell (Shell.groovy:114) at org.codehaus.groovy.tools.shell.Shell$leftShift$0 (null:-1) at org.codehaus.groovy.tools.shell.ShellRunner (ShellRunner.groovy:88) at org.codehaus.groovy.tools.shell.InteractiveShellRunner (InteractiveShellRunner.groovy:-1) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:-2) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl (DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method (Method.java:498) at org.codehaus.groovy.reflection.CachedMethod (CachedMethod.java:90) at groovy.lang.MetaMethod (MetaMethod.java:233) at groovy.lang.MetaClassImpl (MetaClassImpl.java:1054) at org.codehaus.groovy.runtime.ScriptBytecodeAdapter (ScriptBytecodeAdapter.java:128) at org.codehaus.groovy.runtime.ScriptBytecodeAdapter (ScriptBytecodeAdapter.java:148) at org.codehaus.groovy.tools.shell.InteractiveShellRunner (InteractiveShellRunner.groovy:100) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:-2) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl (DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method (Method.java:498) at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite$PogoCachedMethodSiteNoUnwrapNoCoerce (PogoMetaMethodSite.java:267) at org.codehaus.groovy.runtime.callsite.PogoMetaMethodSite (PogoMetaMethodSite.java:52) at org.codehaus.groovy.runtime.callsite.AbstractCallSite (AbstractCallSite.java:137) at org.codehaus.groovy.tools.shell.ShellRunner (ShellRunner.groovy:57) at org.codehaus.groovy.tools.shell.InteractiveShellRunner (InteractiveShellRunner.groovy:-1) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:-2) at sun.reflect.NativeMethodAccessorImpl (NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl (DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method (Method.java:498) at org.codehaus.groovy.reflection.CachedMethod (CachedMethod.java:90) at groovy.lang.MetaMethod (MetaMethod.java:233) at groovy.lang.MetaClassImpl (MetaClassImpl.java:1054) at org.codehaus.groovy.runtime.ScriptBytecodeAdapter (ScriptBytecodeAdapter.java:128) at org.codehaus.groovy.runtime.ScriptBytecodeAdapter (ScriptBytecodeAdapter.java:148) at org.codehaus.groovy.tools.shell.InteractiveShellRunner (InteractiveShellRunner.groovy:66) at java_lang_Runnable$run (null:-1) at org.codehaus.groovy.runtime.callsite.CallSiteArray (CallSiteArray.java:42) at org.codehaus.groovy.runtime.callsite.AbstractCallSite (AbstractCallSite.java:108) at org.codehaus.groovy.runtime.callsite.AbstractCallSite (AbstractCallSite.java:112) at org.codehaus.groovy.tools.shell.Groovysh (Groovysh.groovy:463) at org.codehaus.groovy.tools.shell.Groovysh (Groovysh.groovy:402) at org.apache.sqoop.shell.SqoopShell (SqoopShell.java:128) sqoop:000>
报错原因：
(1) 查看详细报错情况
sqoop:000> set option --name verbose --value true
(2) 发现报错日志里面有这么一句话
java.lang.ClassNotFoundException: org.codehaus.jackson.map.JsonMappingException
(3) 可以判断出没有这个jar包
可以试着将这jar包拷进sqoop2的jar包目录。
报错解决：
(1) 进入到CDH存放jar包的目录
cd /opt/cloudera/parcels/CDH-5.15.1-1.cdh5.15.1.p0.4/jars/
(2) 将 jackson-core-asl-1.8.8.jar 和 jackson-mapper-asl-1.8.8.jar 复制到安装sqoop2服务器下 /var/lib/sqoop2
cp jackson-core-asl-1.8.8.jar jackson-mapper-asl-1.8.8.jar /var/lib/sqoop2
(3) 重启sqoop2服务，报错解决。