Unable to remote connect VisualVM to CentOS

Question

I am new to VisualVM and trying to monitor some application which is deployed on Tomcat 9 CentOS server. I have installed VisualVM on my Windows laptop and trying to remote connect to the JVM on the CentOS server, but nothing is displayed (message on VisualVM: Not supported for this JVM).

Please find below Java version installed on CentOS server:

[root@localhost bin]# java -version
java version "1.8.0_162"
Java(TM) SE Runtime Environment (build 1.8.0_162-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.162-b12, mixed mode)

Based on the online resource I saw, I need to enable JMX on Tomcat, so I have added the following properties in my setenv.sh (in tomcat/bin folder) file:

export CATALINA_OPTS="\
-Dcom.sun.management.jmxremote \
-Dcom.sun.management.jmxremote.port=8999 \
-Dcom.sun.management.jmxremote.authenticate=false \
-Dcom.sun.management.jmxremote.ssl=false"

I have downloaded the latest VisualVM and created a remote host via File->Add Remote Host. Then Add JMX Connection info as follows:

connection:dymmyip:8999
username  :user
Password  :dummyPassword
uncheck   :do not require ssl

When I try to connect, the following screen is displayed:

Can anyone tell me please what I am missing here?

Stéphane Millien · Answer

You can add the missing =true in your setenv.sh

export CATALINA_OPTS="\
-Dcom.sun.management.jmxremote=true \
-Dcom.sun.management.jmxremote.port=8999 \
-Dcom.sun.management.jmxremote.authenticate=false \
-Dcom.sun.management.jmxremote.ssl=false \
-Dcom.sun.management.jmxremote.local.only=false"

You have to chmod you setenv.sh too:

$ cd /bin
$ chmod a+x setenv.sh

Be sure it is not a firewall issue. Test the connection with telnet dummyip 8999

Be sure using the same JVM on both VisualVM and Tomcat. (Be careful with architecture too: 32 or 64bits)

You can get the last release of VisualVM here.
To install it:

$ [ -f "/usr/bin/visualvm" ] && sudo mv /usr/bin/visualvm{,.old}
$ wget https://github.com/oracle/visualvm/releases/download/2.1.4/visualvm_214.zip
$ unzip visualvm_214.zip
$ sudo mv visualvm_214 /opt/
$ sudo ln -s /opt/visualvm_214/bin/visualvm /usr/bin/

$ visualvm --jdkhome /usr/lib/jvm/java-17-openjdk-amd64

Use the path you want in --jdkhome.

Unable to remote connect VisualVM to CentOS

1 Answers