hadoop之jps

简介： 
jps(Java Virtual Machine Process Status Tool)是JDK提供的一个显示当前全部java进程pid的命令，简单实用，很是适合在linux/unix平台上简单察看当前java进程的一些简单状况。 使用它前是jdk安装正确，环境变量设置正确。因为jps是一个工具使用的很是普遍，因此jdk设置的PATH最好是全局变量，这样全部的用户均可以使用。

用法：

man jps

[root@hd1 ~]# man jps
jps(1)                         Monitoring Tools                         jps(1)

NAME
       jps - Lists the instrumented Java Virtual Machines (JVMs) on the target system. This command is experimental and unsupported.

SYNOPSIS
       jps [ options ] [ hostid ]

       options
              Command-line options. See Options.

       hostid The identifier of the host for which the process report should be generated. The hostid can include optional components that indicate the communications protocol,
              port number, and other implementation specific data. See Host Identifier.

DESCRIPTION
       The jps command lists the instrumented Java HotSpot VMs on the target system. The command is limited to reporting information on JVMs for which it has the access
       permissions.

       If the jps command is run without specifying a hostid, then it searches for instrumented JVMs on the local host. If started with a hostid, then it searches for JVMs on
       the indicated host, using the specified protocol and port. A jstatd process is assumed to be running on the target host.

       The jps command reports the local JVM identifier, or lvmid, for each instrumented JVM found on the target system. The lvmid is typically, but not necessarily, the
       operating system’s process identifier for the JVM process. With no options, jps lists each Java application’s lvmid followed by the short form of the application’s class
       name or jar file name. The short form of the class name or JAR file name omits the class’s package information or the JAR files path information.

       The jps command uses the Java launcher to find the class name and arguments passed to the main method. If the target JVM is started with a custom launcher, then the class
       or JAR file name and the arguments to the main method are not available. In this case, the jps command outputs the string Unknown for the class name or JAR file name and
       for the arguments to the main method.

       The list of JVMs produced by the jps command can be limited by the permissions granted to the principal running the command. The command only lists the JVMs for which the
       principle has access rights as determined by operating system-specific access control mechanisms.

OPTIONS
       The jps command supports a number of options that modify the output of the command. These options are subject to change or removal in the future.

       -q
              Suppresses the output of the class name, JAR file name, and arguments passed to the main method, producing only a list of local JVM identifiers.

       -m
              Displays the arguments passed to the main method. The output may be null for embedded JVMs.

       -l
              Displays the full package name for the application’s main class or the full path name to the application’s JAR file.

       -v
              Displays the arguments passed to the JVM.

       -V
              Suppresses the output of the class name, JAR file name, and arguments passed to the main method, producing only a list of local JVM identifiers.

       -Joption
              Passes option to the JVM, where option is one of the options described on the reference page for the Java application launcher. For example, -J-Xms48m sets the
              startup memory to 48 MB. See java(1).

HOST IDENTIFIER
       The host identifier, or hostid is a string that indicates the target system. The syntax of the hostid string corresponds to the syntax of a URI:

       [protocol:][[//]hostname][:port][/servername]

       protocol
              The communications protocol. If the protocol is omitted and a hostname is not specified, then the default protocol is a platform-specific, optimized, local
              protocol. If the protocol is omitted and a host name is specified, then the default protocol is rmi.

       hostname
              A hostname or IP address that indicates the target host. If you omit the hostname parameter, then the target host is the local host.

       port   The default port for communicating with the remote server. If the hostname parameter is omitted or the protocol parameter specifies an optimized, local protocol,
              then the port parameter is ignored. Otherwise, treatment of the port parameter is implementation specific. For the default rmi protocol, the port parameter
              indicates the port number for the rmiregistry on the remote host. If the port parameter is omitted, and the protocol parameter indicates rmi, then the default
              rmiregistry port (1099) is used.

       servername
              The treatment of this parameter depends on the implementation. For the optimized, local protocol, this field is ignored. For the rmi protocol, this parameter is a
              string that represents the name of the RMI remote object on the remote host. See the jstatd command -noption for more information.

OUTPUT FORMAT
       The output of the jps command follows the following pattern:

       lvmid [ [ classname | JARfilename | "Unknown"] [ arg* ] [ jvmarg* ] ]

       All output tokens are separated by white space. An arg value that includes embedded white space introduces ambiguity when attempting to map arguments to their actual
       positional parameters.

       Note: It is recommended that you do not write scripts to parse jps output because the format might change in future releases. If you write scripts that parse jps output,
       then expect to modify them for future releases of this tool.

EXAMPLES
       This section provides examples of the jps command.

       List the instrumented JVMs on the local host:

       jps
       18027 Java2Demo.JAR
       18032 jps
       18005 jstat

       The following example lists the instrumented JVMs on a remote host. This example assumes that the jstat server and either the its internal RMI registry or a separate
       external rmiregistry process are running on the remote host on the default port (port 1099). It also assumes that the local host has appropriate permissions to access the
       remote host. This example also includes the -l option to output the long form of the class names or JAR file names.

       jps -l remote.domain
       3002 /opt/jdk1.7.0/demo/jfc/Java2D/Java2Demo.JAR
       2857 sun.tools.jstatd.jstatd

       The following example lists the instrumented JVMs on a remote host with a non-default port for the RMI registry. This example assumes that the jstatd server, with an
       internal RMI registry bound to port 2002, is running on the remote host. This example also uses the -m option to include the arguments passed to the main method of each
       of the listed Java applications.

       jps -m remote.domain:2002
       3002 /opt/jdk1.7.0/demo/jfc/Java2D/Java2Demo.JAR
       3102 sun.tools.jstatd.jstatd -p 2002

SEE ALSO
       · java(1)

       · jstat(1)

       · jstatd(1)

       · rmiregistry(1)

从以上可知：jps  -vV -m -l -q 几个选项，格式 jps [ options ] [ hostid ]

[hadoop@hd1 sbin]$ jps
2278 ResourceManager
2120 SecondaryNameNode
2538 Jps
1919 NameNode

[hadoop@hd1 sbin]$ jps -q
2560
2278
2120
1919

[hadoop@hd1 sbin]$ jps -m
2595 Jps -m
2278 ResourceManager
2120 SecondaryNameNode
1919 NameNode

[hadoop@hd1 sbin]$ jps -l
2278 org.apache.hadoop.yarn.server.resourcemanager.ResourceManager
2120 org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode
1919 org.apache.hadoop.hdfs.server.namenode.NameNode
2607 sun.tools.jps.Jps

hadoop@hd1 sbin]$ jps -v
2278 ResourceManager -Dproc_resourcemanager -Xmx1000m -Dhadoop.log.dir=/usr/hadoop/hadoop-2.7.1/logs -Dyarn.log.dir=/usr/hadoop/hadoop-2.7.1/logs -Dhadoop.log.file=yarn-hadoop-resourcemanager-hd1.log -Dyarn.log.file=yarn-hadoop-resourcemanager-hd1.log -Dyarn.home.dir= -Dyarn.id.str=hadoop -Dhadoop.root.logger=INFO,RFA -Dyarn.root.logger=INFO,RFA -Djava.library.path=/usr/hadoop/hadoop-2.7.1/lib/native -Dyarn.policy.file=hadoop-policy.xml -Dhadoop.log.dir=/usr/hadoop/hadoop-2.7.1/logs -Dyarn.log.dir=/usr/hadoop/hadoop-2.7.1/logs -Dhadoop.log.file=yarn-hadoop-resourcemanager-hd1.log -Dyarn.log.file=yarn-hadoop-resourcemanager-hd1.log -Dyarn.home.dir=/usr/hadoop/hadoop-2.7.1 -Dhadoop.home.dir=/usr/hadoop/hadoop-2.7.1 -Dhadoop.root.logger=INFO,RFA -Dyarn.root.logger=INFO,RFA -Djava.library.path=/usr/hadoop/hadoop-2.7.1/lib/native
2120 SecondaryNameNode -Dproc_secondarynamenode -Xmx1000m -Djava.net.preferIPv4Stack=true -Dhadoop.log.dir=/usr/hadoop/hadoop-2.7.1/logs -Dhadoop.log.file=hadoop.log -Dhadoop.home.dir=/usr/hadoop/hadoop-2.7.1 -Dhadoop.id.str=hadoop -Dhadoop.root.logger=INFO,console -Djava.library.path=/usr/hadoop/hadoop-2.7.1/lib/native -Dhadoop.policy.file=hadoop-policy.xml -Djava.net.preferIPv4Stack=true -Djava.net.preferIPv4Stack=true -Djava.net.preferIPv4Stack=true -Dhadoop.log.dir=/usr/hadoop/hadoop-2.7.1/logs -Dhadoop.log.file=hadoop-hadoop-secondarynamenode-hd1.log -Dhadoop.home.dir=/usr/hadoop/hadoop-2.7.1 -Dhadoop.id.str=hadoop -Dhadoop.root.logger=INFO,RFA -Djava.library.path=/usr/hadoop/hadoop-2.7.1/lib/native -Dhadoop.policy.file=hadoop-policy.xml -Djava.net.preferIPv4Stack=true -Dhadoop.security.logger=INFO,RFAS -Dhdfs.audit.logger=INFO,NullAppender -Dhadoop.security.logger=INFO,RFAS -Dhdfs.audit.logger=INFO,NullAppender -Dhadoop.security.logger=INFO,RFAS -Dhdfs.audit.logger=INFO,NullAppender -Dhadoop.security.logger=INFO,RFAS
2617 Jps -Denv.class.path=.:.::/usr/java/jdk1.8.0_11/lib:/usr/java/jdk1.8.0_11/jre/lib:/usr/java/jdk1.8.0_11/lib:/usr/java/jdk1.8.0_11/jre/lib -Dapplication.home=/usr/java/jdk1.8.0_11 -Xms8m
1919 NameNode -Dproc_namenode -Xmx1000m -Djava.net.preferIPv4Stack=true -Dhadoop.log.dir=/usr/hadoop/hadoop-2.7.1/logs -Dhadoop.log.file=hadoop.log -Dhadoop.home.dir=/usr/hadoop/hadoop-2.7.1 -Dhadoop.id.str=hadoop -Dhadoop.root.logger=INFO,console -Djava.library.path=/usr/hadoop/hadoop-2.7.1/lib/native -Dhadoop.policy.file=hadoop-policy.xml -Djava.net.preferIPv4Stack=true -Djava.net.preferIPv4Stack=true -Djava.net.preferIPv4Stack=true -Dhadoop.log.dir=/usr/hadoop/hadoop-2.7.1/logs -Dhadoop.log.file=hadoop-hadoop-namenode-hd1.log -Dhadoop.home.dir=/usr/hadoop/hadoop-2.7.1 -Dhadoop.id.str=hadoop -Dhadoop.root.logger=INFO,RFA -Djava.library.path=/usr/hadoop/hadoop-2.7.1/lib/native -Dhadoop.policy.file=hadoop-policy.xml -Djava.net.preferIPv4Stack=true -Dhadoop.security.logger=INFO,RFAS -Dhdfs.audit.logger=INFO,NullAppender -Dhadoop.security.logger=INFO,RFAS -Dhdfs.audit.logger=INFO,NullAppender -Dhadoop.security.logger=INFO,RFAS -Dhdfs.audit.logger=INFO,NullAppender -Dhadoop.security.logger=INFO,RFAS

[hadoop@hd1 sbin]$ jps -V
2627 Jps
2278 ResourceManager
2120 SecondaryNameNode
1919 NameNode

这个hostid 颇有用，能够查看远程主机的进程状态，不过前提是须要开放一个jvm端口，[protocol:][[//]hostname][:port][/servername]

 

生产环境jps 报错process information unavailable处理流程

• 1.jps找到各个进程号
• 2.ps -ef|grep pid是否存在（这步很关键要作判断查看进程是否存在）
• 3.假如进程不存在，咱们能够去该/tmp/hsperfdata_xxx去删除
• 4.若是存在千万别删，本身查看是不能够的，切换到启动HDFS进程的用户下(通常是hadoop用户) 再用jps即显示正常。