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https://issues.apache.org/jira/browse/HBASE-10289?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13978028#comment-13978028
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Qiang Tian commented on HBASE-10289:
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Hi Demai Ni, stack,
I took a look. below is the details.
the problem is JMX created 2 additional random ports besides the port specified
by "com.sun.management.jmxremote.port".
One port is RMI server port, the other is used by Java Attach API for local
attach purpose(see more details below)
it looks it has been the case for long time. prior effort focused on
customizing the RMI server port, because the port is used by client -- when
firewall is configured, client just cannot connect to JMX, for example:
http://olegz.wordpress.com/2009/03/23/jmx-connectivity-through-the-firewall/
there is some artifcat to address it as well, e.g. :
http://tomcat.apache.org/tomcat-7.0-doc/config/listeners.html#JMX_Remote_Lifecycle_Listener_-_org.apache.catalina.mbeans.JmxRemoteLifecycleListener
both registry port(rmiRegistryPortPlatform) and RMI server
port(rmiServerPortPlatform) can be configured, and authentication is supported.
Sun JDK realized this problem, the RMI server port can be configured via
"com.sun.management.jmxremote.rmi.port", since JDK7u4.
then what about the local attach port, which is also random?
According to
http://stackoverflow.com/questions/20884353/why-java-opens-3-ports-when-jmx-is-configured,
this feature can be disabled by "-XX:+DisableAttachMechanism" (there is no
clear description about it in official link
http://docs.oracle.com/javase/7/docs/technotes/tools/windows/java.html), but
the guy tested it just does not work, and recently he opened defect against
java: http://bugs.java.com/bugdatabase/view_bug.do?bug_id=8035404
> Avoid random port usage by default JMX Server. Create Custome JMX server
> ------------------------------------------------------------------------
>
> Key: HBASE-10289
> URL: https://issues.apache.org/jira/browse/HBASE-10289
> Project: HBase
> Issue Type: Improvement
> Reporter: nijel
> Priority: Minor
> Fix For: 0.99.0
>
> Attachments: HBASE-10289-v4.patch, HBASE-10289.patch,
> HBASE-10289_1.patch, HBASE-10289_2.patch, HBASE-10289_3.patch
>
>
> If we enable JMX MBean server for HMaster or Region server through VM
> arguments, the process will use one random which we cannot configure.
> This can be a problem if that random port is configured for some other
> service.
> This issue can be avoided by supporting a custom JMX Server.
> The ports can be configured. If there is no ports configured, it will
> continue the same way as now.
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