Thank you Yuki, this explains it.
I am used to working on C* 2.1 in production where this JVM flag is not enabled.


On Wed, 19 Sep 2018 at 00:29, Yuki Morishita <mor.yuki@gmail.com> wrote:
This is because Cassandra sets -XX:+PerfDisableSharedMem JVM option by default.
This prevents tools such as jps to list jvm processes.
See https://issues.apache.org/jira/browse/CASSANDRA-9242 for detail.

You can work around by doing what Riccardo said.
On Tue, Sep 18, 2018 at 9:41 PM Philip Ó Condúin
<philipoconduin@gmail.com> wrote:
>
> Hi Riccardo,
>
> Yes that works for me:
>
> Welcome to JMX terminal. Type "help" for available commands.
> $> open localhost:7199
> #Connection to localhost:7199 is opened
> $>domains
> #following domains are available
> JMImplementation
> ch.qos.logback.classic
> com.sun.management
> java.lang
> java.nio
> java.util.logging
> org.apache.cassandra.db
> org.apache.cassandra.hints
> org.apache.cassandra.internal
> org.apache.cassandra.metrics
> org.apache.cassandra.net
> org.apache.cassandra.request
> org.apache.cassandra.service
> $>
>
> I can work with this :-)
>
> Not sure why the JVM is not listed when issuing the JVMS command, maybe its a server setting, our production servers find the Cass JVM.  I've spent half the day trying to figure it out so I think I'll just put it to bed now and work on something else.
>
> Regards,
> Phil
>
> On Tue, 18 Sep 2018 at 13:34, Riccardo Ferrari <ferrarir@gmail.com> wrote:
>>
>> Hi Philip,
>>
>> I've used jmxterm myself without any problems particular problems. On my systems too, I don't get the cassandra daemon listed when issuing the `jvms` command but I never spent much time investigating it.
>> Assuming you have not changed anything relevant in the cassandra-env.sh you can connect using jmxterm by issuing 'open 127.0.0.1:7199'. Would that work for you?
>>
>> HTH,
>>
>>
>>
>> On Tue, Sep 18, 2018 at 2:00 PM, Philip Ó Condúin <philipoconduin@gmail.com> wrote:
>>>
>>> Further info:
>>>
>>> I would expect to see the following when I list the jvm's:
>>>
>>> Welcome to JMX terminal. Type "help" for available commands.
>>> $>jvms
>>> 25815    (m) - org.apache.cassandra.service.CassandraDaemon
>>> 17628    ( ) - jmxterm-1.0-alpha-4-uber.jar
>>>
>>> But jmxtem is not picking up the JVM for Cassandra for some reason.
>>>
>>> Can someone point me in the right direction?  Is there settings in the cassandra-env.sh file I need to amend to get jmxterm to find the cass jvm?
>>>
>>> Im not finding much about it on google.
>>>
>>> Thanks,
>>> Phil
>>>
>>>
>>> On Tue, 18 Sep 2018 at 12:09, Philip Ó Condúin <philipoconduin@gmail.com> wrote:
>>>>
>>>> Hi All,
>>>>
>>>> I need a little advice.  I'm trying to access the JMX terminal using jmxterm-1.0-alpha-4-uber.jar with a very simple default install of C* 3.11.3
>>>>
>>>> I keep getting the following:
>>>>
>>>> [cassandra@reaper-1 conf]$ java -jar jmxterm-1.0-alpha-4-uber.jar
>>>> Welcome to JMX terminal. Type "help" for available commands.
>>>> $>open 1666
>>>> #NullPointerException: No such PID 1666
>>>> $>
>>>>
>>>> C* is running with a PID of 1666.  I've tried setting JMX_LOCAL=no and have even created a new VM to test it.
>>>>
>>>> Does anyone know what I might be doing wrong here?
>>>>
>>>> Kind Regards,
>>>> Phil
>>>>
>>>
>>>
>>> --
>>> Regards,
>>> Phil
>>
>>
>
>
> --
> Regards,
> Phil


--
Regards,
Phil