Details
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Bug
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Status: Resolved (View Workflow)
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Major
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Resolution: Fixed
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Jenkins Core > 2.61.X
Description
The latest version of Jenkins core uses Jetty 9.4, this version seems changes the way to manage the session cache and now it is infinite by default, this makes that the session cache is not cleaned with the time and cause a memory leak.
This script gets the EvictionPolicy value and returns -1
import net.bull.javamelody.* def sessionMapField = SessionListener.class.getDeclaredField('SESSION_MAP_BY_ID') sessionMapField.setAccessible(true) def sessions = sessionMapField.get(null) for (def sessionKV : sessions) { def session = sessionKV.value println session.getSessionHandler().getSessionCache().getEvictionPolicy() }
Jetty was upgraded from 9.2 to 9.4 in Jenkins 2.61, The old Jetty uses a different caching mechanism, which seems to have a non-infinite default eviction policy
The workaround is to place this script at JENKINS_HOME/init.groovy.d to set the eviction policy to 30 min.
import net.bull.javamelody.* def sessionMapField = SessionListener.class.getDeclaredField('SESSION_MAP_BY_ID') sessionMapField.setAccessible(true) def sessions = sessionMapField.get(null) for (def sessionKV : sessions) { def session = sessionKV.value session.getSessionHandler().getSessionCache().setEvictionPolicy(1800) }
These are other utility scripts to check the leak.
This script list the sessions
import net.bull.javamelody.* println SessionListener.getSessionCount() + " sessions:" def sessioninfos = SessionListener.getAllSessionsInformations() for (sessioninfo in sessioninfos) { println sessioninfo }
This script returns the number of sessions in cache
import net.bull.javamelody.* def sessionMapField = SessionListener.class.getDeclaredField('SESSION_MAP_BY_ID') sessionMapField.setAccessible(true) def sessions = sessionMapField.get(null) for (def sessionKV: sessions) { def session = sessionKV.value def sessionCache = session.getSessionHandler().getSessionCache() def sessionsField = sessionCache.class.getDeclaredField('_sessions') sessionsField.setAccessible(true) println sessionsField.get(sessionCache).size() }
This script force to clear the session cache
import net.bull.javamelody.* def sessionMapField = SessionListener.class.getDeclaredField('SESSION_MAP_BY_ID') sessionMapField.setAccessible(true) def sessions = sessionMapField.get(null) for (def sessionKV: sessions) { def session = sessionKV.value def sessionCache = session.getSessionHandler().getSessionCache() def sessionsField = sessionCache.class.getDeclaredField('_sessions') sessionsField.setAccessible(true) def sessionKeys = sessionsField.get(sessionCache).keys() for (def sessionKey: sessionKeys) { sessionCache.delete(sessionKey) } }
Attachments
Issue Links
Activity
The fix has been integrated towards 2.110.
It may be considered as LTS candidate since we decoupled the meaty Jetty update part
Code changed in jenkins
User: Oleg Nenashev
Path:
war/pom.xml
http://jenkins-ci.org/commit/jenkins/805a7ab57d4d25f8c5565c5af0b16b36a780a8c9
Log:
JENKINS-49596 - Update Winstone to 4.1.2 (#3307)
JENKINS-49596- Update Winstone to 4.1.1
JENKINS-49596- Pick 4.1.2 with extended session eviction defaults
(cherry picked from commit 852ecdc5f2a7802fa74f425bd17ba028f787b2c1)
marc macintyre
added a comment - Prior to this fix, I'd been setting --sessionTimeout=NNNNN in my java options to extend the session. Is there an equivalent way to set the eviction policy to longer than 30 minutes, or is my only option to add a groovy script to JENKINS_HOME/init.groovy.d?
marc macintyre
added a comment - Prior to this fix, I'd been setting --sessionTimeout=NNNNN in my java options to extend the session. Is there an equivalent way to set the eviction policy to longer than 30 minutes, or is my only option to add a groovy script to JENKINS_HOME/init.groovy.d? marcmac Based on the README I think you want to pass --sessionEviction=foo in addition to --sessionTimeout=foo.
Code changed in jenkins
User: Oleg Nenashev
Path:
CHANGELOG.md
http://jenkins-ci.org/commit/winstone/9137572c6fe1bdb3ef510be5ee0ee9fbc9f56d43
Log:
JENKINS-49596- Noting 4.1.2