Java Garbage Collection - Revision history

Pio2pio: /* Memory allocation */

2019-11-22T09:07:27Z

Memory allocation

← Older revision		Revision as of 11:07, 22 November 2019
Line 97:		Line 97:
	= Memory allocation =		= Memory allocation =
	[https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/parallel.html#default_heap_size Java recommends] heap of 25% of full memory for a container. It's 1/64 for initial and 1/4 for MAX.		[https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/parallel.html#default_heap_size Java recommends] heap of 25% of full memory for a container. It's 1/64 for initial and 1/4 for MAX.

			= Monitor Java =
			Java does expose mBeans as it's metrics. This is part of JMX implementation.

			== [https://jolokia.org/ Jolokia] ==
			In short, it exposes mBeans / JMX protocol over HTTP Rest api.


			Jolokia is a JMX-HTTP bridge giving an alternative to JSR-160 connectors. It is an agent based approach with support for many platforms. In addition to basic JMX operations it enhances JMX remoting with unique features like bulk requests and fine grained security policies.

			<source lang=bash>
			ssh to wso2@server
			wget https://search.maven.org/remotecontent?filepath=org/jolokia/jolokia-osgi/1.6.2/jolokia-osgi-1.6.2.jar -O jolokia-osgi-1.6.2.jar
			chown wso2:wso2 jolokia-osgi-1.6.2.jar
			sudo cp jolokia-osgi-1.6.2.jar <PRODUCT-HOME>/repository/components/dropins # dir where jar's are loaded into runtime
			sudo systemctl restart wso2.service ; tail -f <PRODUCT-HOME>/repository/logs/wso2carbon.log
			# OOB deployment is not user/password secured
			curl https://localhost:9443/jolokia/version -k \| jq # use port 9763 for http (noSSL)
			</source>
			<source lang=json>
			{
			"request": {
			"type": "version"
			},
			"value": {
			"agent": "1.6.2",
			"protocol": "7.2",
			"config": {
			"listenForHttpService": "true",
			"authIgnoreCerts": "false",
			"agentId": "10.0.10.1-4018-52d95d2c-osgi",
			"debug": "false",
			"agentType": "servlet",
			"policyLocation": "classpath:/jolokia-access.xml",
			"agentContext": "/jolokia",
			"serializeException": "false",
			"mimeType": "text/plain",
			"dispatcherClasses": "org.jolokia.http.Jsr160ProxyNotEnabledByDefaultAnymoreDispatcher",
			"authMode": "basic",
			"authMatch": "any",
			"streaming": "true",
			"canonicalNaming": "true",
			"historyMaxEntries": "10",
			"allowErrorDetails": "true",
			"allowDnsReverseLookup": "true",
			"realm": "jolokia",
			"includeStackTrace": "true",
			"useRestrictorService": "false",
			"debugMaxEntries": "100"
			},
			"info": {
			"product": "equinox",
			"vendor": "Eclipse",
			"version": "3.9.1.v20130814-1242"
			}
			},
			"timestamp": 1574350467,
			"status": 200
			}
			</source>


			Other endpoints
			<source>
			http://localhost:9763/jolokia/list # list all MBeans
			http://localhost:9763/jolokia/read/org.apache.synapse:Name=https-sender,Type=PassThroughConnections/ActiveConnections # WSO2 ESB MBean
			http://localhost:9763/jolokia/read/java.lang:type=Memory/HeapMemoryUsage # Reading Heap Memory
			</source>

			;References
			* [https://medium.com/@maanadev/a-way-to-monitoring-jvm-in-kubernetes-3affb5158ad9 Monitoring JVM in Kubernetes] in this example WSO2 application
			* [https://github.com/wso2/docs-ei/blob/master/en/micro-integrator/docs/administer-and-observe/jmx_monitoring.md JMX Monitoring] using Jolokia
			* [https://docs.wso2.com/display/ADMIN44x/JMX-Based+Monitoring#JMX-BasedMonitoring-MonitoringaWSO2productwithJolokia Carbon JMX Monitoring] using Jolokia]

			== [https://hawt.io/docs/get-started/ hawt.io] ==
			Hawtio consists of 2 parts: an AngularJS applicaton and a Java backend, which proxies the communication between the frontend and Jolokia endpoints. The frontend has access to all JMX attributes and operations available in Java applications running locally and remotely.

Pio2pio: /* JMX - Java Management Extensions */

2019-11-05T15:01:54Z

JMX - Java Management Extensions

@@ Line 61: / Line 61: @@
 </source>
 = JMX - Java Management Extensions =
 *[https://www.elastic.co/blog/monitoring-java-applications-with-metricbeat-and-jolokia Monitoring Java Applications with Metricbeat and Jolokia]
 == [https://docs.oracle.com/javase/7/docs/technotes/guides/management/jconsole.html Jsonsole] ==

Pio2pio: /* JMX */

2019-11-05T14:02:11Z

JMX

← Older revision		Revision as of 16:02, 5 November 2019
Line 60:		Line 60:
	sudo -u <user-of-PID> ./thread-analyze.sh 1632 5 10s		sudo -u <user-of-PID> ./thread-analyze.sh 1632 5 10s
	</source>		</source>
	= JMX =		= JMX - Java Management Extensions =
	*[https://www.elastic.co/blog/monitoring-java-applications-with-metricbeat-and-jolokia Monitoring Java Applications with Metricbeat and Jolokia]		*[https://www.elastic.co/blog/monitoring-java-applications-with-metricbeat-and-jolokia Monitoring Java Applications with Metricbeat and Jolokia]
	== [https://docs.oracle.com/javase/7/docs/technotes/guides/management/jconsole.html Jsonsole] ==		== [https://docs.oracle.com/javase/7/docs/technotes/guides/management/jconsole.html Jsonsole] ==

Pio2pio: /* JMX */

2019-11-05T13:31:47Z

JMX

← Older revision		Revision as of 15:31, 5 November 2019
Line 61:		Line 61:
	</source>		</source>
	= JMX =		= JMX =
			*[https://www.elastic.co/blog/monitoring-java-applications-with-metricbeat-and-jolokia Monitoring Java Applications with Metricbeat and Jolokia]
	== [https://docs.oracle.com/javase/7/docs/technotes/guides/management/jconsole.html Jsonsole] ==		== [https://docs.oracle.com/javase/7/docs/technotes/guides/management/jconsole.html Jsonsole] ==
	== [https://visualvm.github.io VisualVM] ==		== [https://visualvm.github.io VisualVM] ==

Pio2pio: /* Analise GC */

2019-11-05T13:30:56Z

Analise GC

← Older revision		Revision as of 15:30, 5 November 2019
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	= ~~Analise~~ GC =		= Analyse GC =
	== Enable GC ==		== Enable GC ==
	Pass following parameters to starting java process		Pass following parameters to starting java process
Line 6:		Line 6:
	</source>		</source>

	== ~~Analise~~ ==		== Analyse ==
	Use GCViewer		Use GCViewer
	<source lang="bash">		<source lang="bash">
Line 60:		Line 60:
	sudo -u <user-of-PID> ./thread-analyze.sh 1632 5 10s		sudo -u <user-of-PID> ./thread-analyze.sh 1632 5 10s
	</source>		</source>
			= JMX =
			== [https://docs.oracle.com/javase/7/docs/technotes/guides/management/jconsole.html Jsonsole] ==
			== [https://visualvm.github.io VisualVM] ==
			Modern replacement for Jconsole.
			:[[File:ClipCapIt-191105-132743.PNG]]

	= Collect heapdump =		= Collect heapdump =

Pio2pio: /* Memory allocation */

2019-10-18T10:50:14Z

Memory allocation

← Older revision		Revision as of 12:50, 18 October 2019
Line 73:		Line 73:

	= Memory allocation =		= Memory allocation =
	Java recommends heap of 25% of full memory for a container.		[https://docs.oracle.com/javase/8/docs/technotes/guides/vm/gctuning/parallel.html#default_heap_size Java recommends] heap of 25% of full memory for a container. It's 1/64 for initial and 1/4 for MAX.

Pio2pio: /* Collect heapdump */

2019-10-18T09:08:32Z

Collect heapdump

← Older revision		Revision as of 11:08, 18 October 2019
Line 71:		Line 71:
	sudo -u <processID-user> jmap -dump:file=$(hostname)-<env>-$(date +"%Y%m%dT%H%M")-heap_dump.bin <process_Id>		sudo -u <processID-user> jmap -dump:file=$(hostname)-<env>-$(date +"%Y%m%dT%H%M")-heap_dump.bin <process_Id>
	</source>		</source>

			= Memory allocation =
			Java recommends heap of 25% of full memory for a container.

Pio2pio: /* Thread Dump */

2019-10-04T17:46:17Z

Thread Dump

← Older revision		Revision as of 19:46, 4 October 2019
Line 52:		Line 52:
	fi		fi
	done		done
			</source>


			Usage
			<source lang="bash">
			sudo -u <user-of-PID> ./thread-analyze.sh <PID> <iterations> <delay-in-secons>s
			sudo -u <user-of-PID> ./thread-analyze.sh 1632 5 10s
	</source>		</source>

Pio2pio: /* Collect heapdump */

2019-10-04T17:43:17Z

Collect heapdump

← Older revision		Revision as of 19:43, 4 October 2019
Line 56:		Line 56:
	= Collect heapdump =		= Collect heapdump =
	<source lang=bash>		<source lang=bash>
			# get PID, remember ps -ef, where -f shows full command
			PID TTY TIME CMD
			12631 ? 6-15:47:42 java
	# the following command should be run as a user of the process		# the following command should be run as a user of the process
			locate jmap # locate jmap location and if not in $PATH use full-path in the command below
	sudo -u <processID-user> jmap -dump:file=heap_dump.bin <process_Id>		sudo -u <processID-user> jmap -dump:file=heap_dump.bin <process_Id>
			sudo -u <processID-user> jmap -dump:file=$(hostname)-<env>-$(date +"%Y%m%dT%H%M")-heap_dump.bin <process_Id>
	</source>		</source>

Pio2pio: /* Thread Dump */

2019-10-03T12:42:57Z

Thread Dump

← Older revision		Revision as of 14:42, 3 October 2019
Line 52:		Line 52:
	fi		fi
	done		done
			</source>

			= Collect heapdump =
			<source lang=bash>
			# the following command should be run as a user of the process
			sudo -u <processID-user> jmap -dump:file=heap_dump.bin <process_Id>
	</source>		</source>