Thanks Marc , we will definitely update this settings and observe 
performance . 

For now below fix worked for me , not observing any issues recently with my 
application  . 

1.upgrade jdk8 version to recommended version (1.8.0_222-b10 and above) . 
2.Install monitoring plugin in Jenkins. 
3.Udate NFS settings with recommended settings (
RPCNFSDCOUNT=16 (default is 8
sunrpc.tcp_slot_table_entries = 128) . 
4.Auto clean up for sessions with scheduler (
https://wiki.jenkins.io/display/JENKINS/Invalidate+Jenkins+HTTP+sessions) 
5.Add monitoring script to monitor active thread , JVM usage , thread 
deadlocks (https://wiki.jenkins.io/display/JENKINS/Monitoring+Scripts )
6.Free cache memory whenever it reaches to MAX memory limit , below steps 
help me to clean cache memory for jenkins master pod. 

I am able to free cache memory for Jenkins master pod docker container . As 
per docker image behaviour its taking resources from k8s node where it is 
deployed . 

You can verify memory usage by below commands from docker container . 

bash-4.4$ cat /sys/fs/cgroup/memory/memory.limit_in_bytes

bash-4.4$ cat /sys/fs/cgroup/memory/memory.max_usage_in_bytes

bash-4.4$ cat /sys/fs/cgroup/memory/memory.stat | grep cache

bash-4.4$ 



Solution , delete *cache memory for k8s node where your Jenkins master pod 
docker container is running* , there will be no downtime required for 
Jenkins service . 
Following document help me : 
https://www.tecmint.com/clear-ram-memory-cache-buffer-and-swap-space-on-linux/
 


Thanks ,
Mahesh

On Monday, January 20, 2020 at 8:07:33 PM UTC+5:30, Mark Waite wrote:
>
> You might install the Jenkins Health Advisor by CloudBees and see if it 
> has suggestions for your instance.  It will check for conditions that have 
> been found to cause problems in other installations and report them to you 
> in a daily e-mail message.
>
> https://jenkins.io/blog/2019/11/22/jenkins-health-advisor-by-cloudbees/  
>
> On Mon, Jan 20, 2020 at 6:49 AM Mahesh Wabale <[email protected] 
> <javascript:>> wrote:
>
>> We are using following JAVA_OPTS CONFIG in Jenkins deployment .
>>
>> "name": "JAVA_OPTS",
>>                 "value": "-XX:+UseG1GC -XX:+ExplicitGCInvokesConcurrent 
>> -XX:+ParallelRefProcEnabled -XX:+UseStringDeduplication 
>> -XX:+UnlockExperimentalVMOptions -XX:G1NewSizePercent=20 
>> -XX:+UnlockDiagnosticVMOptions -XX:NativeMemoryTracking=summary 
>> -XX:G1SummarizeRSetStatsPeriod=1 -Xms2048m -Xmx8192m"   , and 48 GB ram 
>> allocated for master Jenkins pod as per initial observation GC is working 
>> correctly its not going beyond 8 gb . But observing RAM USAGE of master pod 
>> is continusly increasing day by day . Some time it reaches to memory 48 GB 
>> seems like it taking memory for cache .How can we control ram memory size , 
>> or is it possible to free cache memory from Jenkins Docker image which can 
>> solve my problem .
>>
>> On Mon, Jan 20, 2020, 3:45 PM Mahesh Wabale <[email protected] 
>> <javascript:>> wrote:
>>
>>> Thanks Marc , 
>>>
>>> We will check if it helps , Currently we have "maximum durability" 
>>> settings configured now , we are planning to make it to "
>>> performance-optimized"  .  We have observed couple of time disc IO is 
>>> very high sometimes . 
>>>
>>> On Monday, January 20, 2020 at 5:54:38 AM UTC+5:30, Mark Waite wrote:
>>>>
>>>> I'm not aware of an open bug in Jenkins related to being slow over NFS, 
>>>> though Jenkins is quite disc intensive and runs best with local disc 
>>>> drives.
>>>>
>>>> You might refer to the following articles for more information:
>>>>
>>>>    - Jenkins pipeline durability settings documentation 
>>>>    
>>>> <https://www.google.com/url?q=https%3A%2F%2Fjenkins.io%2Fdoc%2Fbook%2Fpipeline%2Fscaling-pipeline%2F%23will-higher-performance-durability-settings-help-me&sa=D&sntz=1&usg=AFQjCNEtvgPugqm3XG5_99K4YYJi6vCf6Q>
>>>>  
>>>>    ("Will Higher-Performance Durability Settings Help Me? Yes, if your 
>>>> Jenkins 
>>>>    instance uses NFS, magnetic storage, runs many Pipelines at once, or 
>>>> shows 
>>>>    high iowait.")
>>>>    - CloudBees NFS guide 
>>>>    <https://support.cloudbees.com/hc/en-us/articles/217479948-NFS-Guide> 
>>>> (multiple 
>>>>    pages of tuning recommendations)
>>>>
>>>>
>>>>
>>>> On Fri, Jan 17, 2020 at 5:42 AM Mahesh Wabale <[email protected]> 
>>>> wrote:
>>>>
>>>>> Hi Team , 
>>>>>
>>>>> We are using observing Jenkins slowness issues for jenkins version 
>>>>> 2.138 in multi branch pipeline project . 
>>>>> We have also used NFS 4.1 . 
>>>>>
>>>>> After Jenkins restart it works for few days but at some stage it stuck 
>>>>> and becomes unresponsive . As per observation only restart will solve 
>>>>> this 
>>>>> issue for next few days . We require frequent restart due to this issue . 
>>>>> Have anyone observed similar issues , or  this is open bug in Jenkins ?   
>>>>>  
>>>>>
>>>>>
>>>>> -- 
>>>>> You received this message because you are subscribed to the Google 
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>>>>> https://groups.google.com/d/msgid/jenkinsci-users/319f90ff-5410-4495-bb46-51d61745b3e8%40googlegroups.com
>>>>>  
>>>>> <https://groups.google.com/d/msgid/jenkinsci-users/319f90ff-5410-4495-bb46-51d61745b3e8%40googlegroups.com?utm_medium=email&utm_source=footer>
>>>>> .
>>>>>
>>>>
>>>>
>>>> -- 
>>>> Thanks!
>>>> Mark Waite
>>>>
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>>>  
>>> <https://groups.google.com/d/msgid/jenkinsci-users/8a711ba9-4433-4e62-9170-50e7f5c82bdd%40googlegroups.com?utm_medium=email&utm_source=footer>
>>> .
>>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
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>> To unsubscribe from this group and stop receiving emails from it, send an 
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>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/jenkinsci-users/CABOY2ebxtXCGqDXKcfk7kzh0CgjvajTmyiOSni4EPF516gy9iA%40mail.gmail.com
>>  
>> <https://groups.google.com/d/msgid/jenkinsci-users/CABOY2ebxtXCGqDXKcfk7kzh0CgjvajTmyiOSni4EPF516gy9iA%40mail.gmail.com?utm_medium=email&utm_source=footer>
>> .
>>
>
>
> -- 
> Thanks!
> Mark Waite
>

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