•  13-10-2022
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Question

I am trying to enable JMX monitoring on Munin

I have followed the guide at:

https://github.com/munin-monitoring/contrib/tree/master/plugins/java/jmx

It tells me:

1) Files from "plugin" folder must be copied to /usr/share/munin/plugins (or another - where your munin plugins located)
2) Make sure that jmx_ executable : chmod a+x /usr/share/munin/plugins/jmx_
3) Copy configuration files that you want to use, from "examples" folder, into /usr/share/munin/plugins folder
4) create links from the /etc/munin/plugins folder to the /usr/share/munin/plugins/jmx_
The name of the link must follow wildcard pattern:
jmx_<configname>,
where configname is the name of the configuration (config filename without extension), for example:
ln -s /usr/share/munin/plugins/jmx_ /etc/munin/plugins/jmx_process_memory

I have done exatly this but whern i run ./jmx_process_memory, I just get:

Error: Could not find or load main class org.munin.plugin.jmx.memory

The actual config file is called java_process_memory.conf, so i have also tried naming the symlink jmx_java_process_memory, but get the same error.

I have had success by naming the symlink jmx_Threads as described here: 

http://blog.johannes-beck.name/?p=160

I can see that org.munin.plugin.jmx.Threads is the name of a class within munin-jmx-plugins.jar, and the other classes seem to work also. But this is not what the Munin guide tells me to do, so is the documentation wrong? What is the purpose of the config files, they must be there for a reason? There are example config files for Tomcat, which is where my real interest lies, so I need to understand this. Without being able the get it working as per the guide though im a bit stuck!

Can anyone put me right on this?

Cheers NFV

Was it helpful?

Solution

I was stuck with somehow the same issue. What i did to get something working a little bit better but still not perfectly.

I'm on RHEL :

[root@bus|in plugins]# cat /etc/munin/plugin-conf.d/munin-node 
[diskstats]
user munin

[iostat_ios]
user munin

[jmx_*]
env.ip 192.168.1.101
env.port 5054         <- being the port configured for your jmx

then

[root@bus|in plugins]# ls -l /etc/munin/plugins/jmx_MultigraphAll 
lrwxrwxrwx 1 root root 29 14 mars  15:36 /etc/munin/plugins/jmx_MultigraphAll -> /usr/share/munin/plugins/jmx_

and I modified the /usr/share/munin/plugins/jmx_ with the following :

#!/bin/sh
# -*- sh -*-
: << =cut

=head1 NAME

jmx_ - Wildcard plugin to monitor Java application servers via JMX

=head1 APPLICABLE SYSTEMS

Tested with Tomcat 4.1/5.0/5.5/6.0 on Sun JVM 5/6 and OpenJDK.

Any JVM that supports JMX should in theory do.

Needs nc in path for autoconf.

=head1 CONFIGURATION

  [jmx_*]
    env.ip 127.0.0.1
    env.port 5400
    env.category jvm
    env.username monitorRole
    env.password SomethingSecret

    env.JRE_HOME /usr/lib/jvm/java-6-sun/jre
    env.JAVA_OPTS -Xmx128m

Needed configuration on the Tomcat side: add

  -Dcom.sun.management.jmxremote \
  -Dcom.sun.management.jmxremote.port=5400 \
  -Dcom.sun.management.jmxremote.ssl=false \
  -Dcom.sun.management.jmxremote.authenticate=false

to CATALINA_OPTS in your startup scripts.

Replace authenticate=false with 
  -Dcom.sun.management.jmxremote.password.file=/etc/tomcat/jmxremote.password \
  -Dcom.sun.management.jmxremote.access.file=/etc/tomcat/jmxremote.access
 ...if you want authentication.

jmxremote.password:
 monitorRole SomethingSecret

jmxremote.access:
 monitorRole readonly

You may need higher access levels for some counters, notably ThreadsDeadlocked.

=head1 BUGS

No encryption supported in the JMX connection.

The plugins available reflect the most interesting aspects of a
JVM runtime.  This should be extended to cover things specific to
Tomcat, JBoss, Glassfish and so on.  Patches welcome.

=head1 AUTHORS

=encoding UTF-8

Mo Amini, Diyar Amin and Younes Hajji, Høgskolen i Oslo/Oslo
University College.

Shell script wrapper and integration by Erik Inge Bolsø, Redpill
Linpro AS.

Previous work on JMX plugin by Aleksey Studnev. Support for
authentication added by Ingvar Hagelund, Redpill Linpro AS.

=head1 LICENSE

GPLv2

=head1 MAGIC MARKERS

 #%# family=auto
 #%# capabilities=autoconf suggest

=cut

MUNIN_JAR="/usr/share/java/munin-jmx-plugins.jar"

if [ "x$JRE_HOME" != "x" ] ; then
  JRE=$JRE_HOME/bin/java
  export JRE_HOME=$JRE_HOME
fi
JAVA_BIN=${JRE:-/opt/jdk/jre/bin/java}

ip=${ip:-192.168.1.101}
port=${port:-5054}

if [ "x$1" = "xsuggest" ] ; then
  echo MultigraphAll
  exit 0
fi

if [ "x$1" = "xautoconf" ] ; then
    NC=`which nc 2>/dev/null`
    if [ "x$NC" = "x" ] ; then
      echo "no (nc not found)"
      exit 0
    fi
    $NC -n -z $ip $port >/dev/null 2>&1
    CONNECT=$?

    $JAVA_BIN -? >/dev/null 2>&1
    JAVA=$?
    if [ $JAVA -ne 0 ] ; then
      echo "no (java runtime not found at $JAVA_BIN)"
      exit 0
    fi

    if [ ! -e $MUNIN_JAR ] ; then
      echo "no (munin jmx classes not found at $MUNIN_JAR)"
      exit 0
    fi

    if [ $CONNECT -eq 0 ] ; then
      echo "yes"
      exit 0
    else
      echo "no (connection to $ip:$port failed)"
      exit 0
    fi
fi

if [ "x$1" = "xconfig" ] ; then
  param=config
else
  param=Tomcat
fi

scriptname=${0##*/}
jmxfunc=${scriptname##*_}
prefix=${scriptname%_*}

if [ "x$jmxfunc" = "x" ] ; then
  echo "error, plugin must be symlinked in order to run"
  exit 1
fi

ip=$ip port=$port $JAVA_BIN -cp $MUNIN_JAR $JAVA_OPTS org.munin.plugin.jmx.$jmxfunc $param $prefix

And you have to add the right permissions and owner:group on what you define as the JRE, for example here :

[root@bus|in plugins]# ls -ld /opt/jdk
drwxrwxr-x 8 nobody nobody 4096  8 oct.  15:03 /opt/jdk

Now I can run (and I can see it's using nobody:nobody as user:group, maybe something to play with in the conf) :

[root@bus|in plugins]# munin-run jmx_MultigraphAll -d
# Processing plugin configuration from /etc/munin/plugin-conf.d/df
# Processing plugin configuration from /etc/munin/plugin-conf.d/fw_
# Processing plugin configuration from /etc/munin/plugin-conf.d/hddtemp_smartctl
# Processing plugin configuration from /etc/munin/plugin-conf.d/munin-node
# Processing plugin configuration from /etc/munin/plugin-conf.d/postfix
# Processing plugin configuration from /etc/munin/plugin-conf.d/sendmail
# Setting /rgid/ruid/ to /99/99/
# Setting /egid/euid/ to /99 99/99/
# Setting up environment
# Environment ip = 192.168.1.101
# Environment port = 5054
# About to run '/etc/munin/plugins/jmx_MultigraphAll'
multigraph jmx_memory
Max.value 2162032640
Committed.value 1584332800
Init.value 1613168640
Used.value 473134248

multigraph jmx_MemoryAllocatedHeap
Max.value 1037959168
Committed.value 1037959168
Init.value 1073741824
Used.value 275414584

multigraph jmx_MemoryAllocatedNonHeap
Max.value 1124073472
Committed.value 546373632
Init.value 539426816
Used.value 197986088

[...]

multigraph jmx_ProcessorsAvailable
ProcessorsAvailable.value 1

Now I'm trying to get it to work for different JVMs on the same host, because this is for a single one. I hope that can help you.

edit : actually I did the modifications to use with several java processes having their own jmx ports.

What you have to add them there :

[root@bus|in plugins]# cat /etc/munin/plugin-conf.d/munin-node 
[diskstats]
user munin

[iostat_ios]
user munin

[admin_jmx_*]
env.ip 192.168.1.101
env.port 5054

[managed_jmx_*]
env.ip 192.168.1.101
env.port 5055

[jboss_jmx_*]
env.ip 192.168.1.101
env.port 1616

and then create the links :

[root@bus|in plugins]# ls -l /etc/munin/plugins/*_jmx_*
lrwxrwxrwx 1 root root 29 14 mars  15:36 /etc/munin/plugins/admin_jmx_MultigraphAll -> /usr/share/munin/plugins/jmx_
lrwxrwxrwx 1 root root 29 14 mars  16:51 /etc/munin/plugins/jboss_jmx_MultigraphAll -> /usr/share/munin/plugins/jmx_
lrwxrwxrwx 1 root root 29 14 mars  16:03 /etc/munin/plugins/managed_jmx_MultigraphAll -> /usr/share/munin/plugins/jmx_

and I commented out the ip and port from the /usr/share/munin/plugins/jmx_ file, but I'm not sure it plays a role.

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