More info: In my case, a reboot is definitely needed. A
disconnect/reconnect does not suffice, nor does rebooting just the
master/controller or the agent in sequence - *the only way I see the
correct jvmOptions being used is by rebooting the entire cluster at once*.
I'm using Jenkins 2.222.3, ssh build agents plugin 1.31.2.
Another probably important piece of info here is that *I have
"ServerAliveCountMax 10" and "ServerAliveInterval 60" in the ssh client on
the Jenkins master/controller, to help keep ssh connections alive for
longer amount of time when agents are very very busy performing builds and
may not have the cycles to respond to the master/controller.*
I'm also using ansible and configuration-as-code plugin (1.43) to configure
*everything* in the jenkins cluster. So, to make a change to the agent
java_options, what I do is:
1. Modify the local jenkins.yml CasC file to include new "jvmOptions"
values for my agent, e.g. my latest:
- permanent:
name: "jenkins-testing-agent-1"
nodeDescription: "Fungible Agent for jenkins-testing"
labelString: ""
mode: "NORMAL"
remoteFS: "/home/jenkins/.jenkins"
launcher:
ssh:
credentialsId: "jenkins_user_on_linux_agent"
host: "jenkins-testing-agent-1"
jvmOptions: "-Dhudson.slaves.WorkspaceList=-
-Dorg.apache.commons.jelly.tags.fmt.timeZone=America/Vancouver *-Xmx4g
-Xms1g* -XX:+AlwaysPreTouch -XX:+HeapDumpOnOutOfMemoryError
-XX:HeapDumpPath=/home/jenkins/.jenkins/support -XX:+UseG1GC
-XX:+UseStringDeduplication -XX:+ParallelRefProcEnabled
-XX:+DisableExplicitGC -XX:+UnlockDiagnosticVMOptions
-XX:+UnlockExperimentalVMOptions -verbose:gc
-Xlog:gc:/home/jenkins/.jenkins/support/gc-%t.log -XX:+PrintGC
-XX:+PrintGCDetails -XX:ErrorFile=/hs_err_%p.log -XX:+LogVMOutput
-XX:LogFile=/home/jenkins/.jenkins/support/jvm.log"
launchTimeoutSeconds: 30
maxNumRetries: 20
port: 22
retryWaitTime: 10
sshHostKeyVerificationStrategy:
"nonVerifyingKeyVerificationStrategy"
2. send the CasC yaml file to <JENKINS_HOME>/jenkins.yml on the
master/controller machine
3. run geerlingguy.jenkins role which, among other things, detects a change
and restarts the jenkins service
4. on Jenkins restart, Jenkins applies the new CasC settings in
jenkins.yaml, and this can be verified as correct in the GUI subsequently
5. the agents are not restarted in this process (which I assert should be
fine/ok)
After my ansible playbook is complete, and all (verifiably correct) config
has been applied to controller/agents, I look at the agent logs and they
appear to have gone back to having the empty jvmOptions like I originally
reported:
SSHLauncher{host='jenkins-testing-agent-1', port=22,
credentialsId='jenkins_user_on_linux_agent', *jvmOptions=''*, javaPath='',
prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=30,
maxNumRetries=20, retryWaitTime=10,
sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy,
tcpNoDelay=true, trackCredentials=true}
At this point, *if I only reboot the agent, when the master/controller
reconnect to it the logs still shows jvmOptions=''*.
*If I then reboot the master/controller, is still shows jvmOptions=''*.
But if (and only iff) I reboot the entire cluster, I get the correct
application of my ssh agent jvmOptions:
SSHLauncher{host='jenkins-testing-agent-1', port=22,
credentialsId='jenkins_user_on_linux_agent',
*jvmOptions='-Dhudson.slaves.WorkspaceList=-
-Dorg.apache.commons.jelly.tags.fmt.timeZone=America/Vancouver -Xmx4g
-Xms1g -XX:+AlwaysPreTouch -XX:+HeapDumpOnOutOfMemoryError
-XX:HeapDumpPath=/home/jenkins/.jenkins/support -XX:+UseG1GC
-XX:+UseStringDeduplication -XX:+ParallelRefProcEnabled
-XX:+DisableExplicitGC -XX:+UnlockDiagnosticVMOptions
-XX:+UnlockExperimentalVMOptions -verbose:gc
-Xlog:gc:/home/jenkins/.jenkins/support/gc-%t.log -XX:+PrintGC
-XX:+PrintGCDetails -XX:ErrorFile=/hs_err_%p.log -XX:+LogVMOutput
-XX:LogFile=/home/jenkins/.jenkins/support/jvm.log'*, javaPath='',
prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=30,
maxNumRetries=20, retryWaitTime=10,
sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy,
tcpNoDelay=true, trackCredentials=true}
Thanks for your help in diagnosing these behaviors. kuisathaverat, let me
know if any of this feels like a bug in ssh-slaves-plugin or
configuration-as-code-plugin.
On Wednesday, September 23, 2020 at 12:01:39 PM UTC-7 Tim Black wrote:
> Thanks everyone, it's working now (see below for details). kuisathaverat,
> these agents have 96GB total RAM. Thanks for the explanation. Our builds
> are very RAM intensive, and I misunderstood that the builds happened within
> the remoting java process. Sounds like you're saying in this case there's
> no reason to give the agent jvm so much RAM. The Cloudbees JVM Best
> Practices page
> <https://docs.cloudbees.com/docs/admin-resources/latest/jvm-troubleshooting/#recommended-options>
> indicates
> the default min/max heap are 1/64 physical RAM / 1/4 physical RAM, but both
> cap out at 1GB. So, before I was setting these options, my agents should
> have been effectively using 1GB/1GB for min/max. As for the other options
> I'm setting in the agents, these are the same options recommended by the
> page linked above (which I'm also using on master/controller). Do these not
> apply to agents as well as masters/controllers?
>
> Also, on the agent machine, my <JENKINS_HOME>/support/all*.logs and
> <JENKINS_HOME>/remoting/logs/* are still empty,; any suggestions how to get
> more logging on the agents?
>
> I didn't have gc or other logging enabled, so I'm still not yet sure what
> the catastrophic problem was, it might not be a java problem at all, since
> I'm not seeing any problems in syslog indicating problems with the jenkins
> remoting process. These are VMware machines, and they just stop themselves,
> so it seems like a kernel panic or something. I have them autorestarting
> now and the problem seems intermittent.
>
> I think the jvmOptions is working as expected now. I think I may not have
> rebooted the jenkins instance but had only rebooted the agents and had only
> restarted the jenkins service on master/controller machine. So apparently
> the change I made required a reboot of the master/controller. Now, signing
> into the agent and looking at the java process for jenkins remoting, I can
> see all the specified args are there:
>
> ```
> jenkins@jenkins-testing-agent-1:~$ ps aux | grep java jenkins 2733 5.1
> 70.4 73509096 69794284 ? Ssl 11:19 0:26 java
> -Dhudson.slaves.WorkspaceList=-
> -Dorg.apache.commons.jelly.tags.fmt.timeZone=America/Vancouver -Xmx64g
> -Xms64g -XX:+AlwaysPreTouch -XX:+HeapDumpOnOutOfMemoryError
> -XX:HeapDumpPath=/home/jenkins/.jenkins/support -XX:+UseG1GC
> -XX:+UseStringDeduplication -XX:+ParallelRefProcEnabled
> -XX:+DisableExplicitGC -XX:+UnlockDiagnosticVMOptions
> -XX:+UnlockExperimentalVMOptions -verbose:gc
> -Xlog:gc:/home/jenkins/.jenkins/support/gc-%t.log -XX:+PrintGC
> -XX:+PrintGCDetails -XX:ErrorFile=/hs_err_%p.log -XX:+LogVMOutput
> -XX:LogFile=/home/jenkins/.jenkins/support/jvm.log -jar remoting.jar
> -workDir /home/jenkins/.jenkins -jar-cache
> /home/jenkins/.jenkins/remoting/jarCache
> ```
>
> I am also now seeing garbage collection logs in support/ as configured:
>
> ```
> jenkins@jenkins-testing-agent-1:~$ ls -la .jenkins/support/ total 32
> drwxr-xr-x 2 jenkins jenkins 4096 Sep 23 11:20 . drwxrwxr-x 6 jenkins
> jenkins 4096 Sep 16 00:27 .. -rw-r--r-- 1 jenkins jenkins 0 Sep 22 11:01
> all_2020-09-22_18.01.37.log -rw-r--r-- 1 jenkins jenkins 0 Sep 22 11:03
> all_2020-09-22_18.03.01.log -rw-r--r-- 1 jenkins jenkins 0 Sep 22 13:04
> all_2020-09-22_20.04.15.log -rw-r--r-- 1 jenkins jenkins 0 Sep 22 15:17
> all_2020-09-22_22.17.09.log -rw-r--r-- 1 jenkins jenkins 0 Sep 22 15:32
> all_2020-09-22_22.32.14.log -rw-r--r-- 1 jenkins jenkins 0 Sep 22 15:56
> all_2020-09-22_22.56.18.log -rw-r--r-- 1 jenkins jenkins 1078 Sep 23 11:18
> all_2020-09-23_18.04.43.log -rw-r--r-- 1 jenkins jenkins 0 Sep 23 11:20
> all_2020-09-23_18.20.07.log -rw-r--r-- 1 jenkins jenkins 194 Sep 23 11:04
> gc-2020-09-23_11-04-04.log -rw-r--r-- 1 jenkins jenkins 194 Sep 23 11:04
> gc-2020-09-23_11-04-24.log -rw-r--r-- 1 jenkins jenkins 194 Sep 23 11:19
> gc-2020-09-23_11-19-32.log -rw-r--r-- 1 jenkins jenkins 546 Sep 23 11:22
> gc-2020-09-23_11-19-50.log -rw-r--r-- 1 jenkins jenkins 4096 Sep 23 11:20
> jvm.log
> ```
> On Wednesday, September 23, 2020 at 10:36:20 AM UTC-7 naresh....@gmail.com
> wrote:
>
>> I think to have those updated settings applied correctly we need to
>> disconnect and launch those agents again instead of just bringing those
>> offline and online, just checking to make sure that we are not missing
>> anything there.
>>
>> On Wednesday, September 23, 2020 at 12:01:46 PM UTC-5 kuisat...@gmail.com
>> wrote:
>>
>>> How much memory those agents have? you set "-Xmx64g -Xms64g" for the
>>> remoting process (not for builds) you agent has to have more than 64GB of
>>> RAM to run any build on it, you grab 64GB only for the remoting process,
>>> and this RAM should be enough to run you builds. The remoting agent usually
>>> does not need more than 256-512MB, this keeps the rest of your agent memory
>>> for builds, agents rarely need JVM options to tune the memory the default
>>> configuration is enough, the only case I will recommend to pass JVM option
>>> is to limit the memory of the agent process.
>>>
>>> the jvmOptions field should work is tested on unit test, if not is and
>>> issue, Which version of Jenksin and ssh build agents plugin do your use?
>>>
>>> El miércoles, 23 de septiembre de 2020 a las 1:21:28 UTC+2,
>>> timb...@gmail.com escribió:
>>>
>>>> I'm using ssh-slaves-plugin
>>>> <https://github.com/jenkinsci/ssh-slaves-plugin> to configure and
>>>> launch 2 ssh agents, and I've specified several java options in these
>>>> agents' config (see photo and text list below), but when these agents are
>>>> launched, the agents' log still shows empty jvmOptions in the ssh launcher
>>>> call. Agent Log excerpt:
>>>>
>>>> SSHLauncher{host='jenkins-testing-agent-1', port=22,
>>>> credentialsId='jenkins_user_on_linux_agent', *jvmOptions=''*,
>>>> javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='',
>>>> launchTimeoutSeconds=30, maxNumRetries=20, retryWaitTime=10,
>>>> sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy,
>>>>
>>>> tcpNoDelay=true, trackCredentials=true}
>>>> [09/22/20 15:56:12] [SSH] Opening SSH connection to
>>>> jenkins-testing-agent-1:22.
>>>> [09/22/20 15:56:16] [SSH] WARNING: SSH Host Keys are not being
>>>> verified. Man-in-the-middle attacks may be possible against this
>>>> connection.
>>>> [09/22/20 15:56:16] [SSH] Authentication successful.
>>>> [09/22/20 15:56:16] [SSH] The remote user's environment is:
>>>> BASH=/usr/bin/bash
>>>> .
>>>> .
>>>> .
>>>> [SSH] java -version returned 11.0.8.
>>>> [09/22/20 15:56:16] [SSH] Starting sftp client. [09/22/20 15:56:16]
>>>> [SSH] Copying latest remoting.jar... Source agent hash is
>>>> 0146753DA5ED62106734D59722B1FA2C. Installed agent hash is
>>>> 0146753DA5ED62106734D59722B1FA2C Verified agent jar. No update is
>>>> necessary. Expanded the channel window size to 4MB
>>>> [09/22/20 15:56:16] [SSH] Starting agent process: cd
>>>> "/home/jenkins/.jenkins" && java -jar remoting.jar -workDir
>>>> /home/jenkins/.jenkins -jar-cache /home/jenkins/.jenkins/remoting/jarCache
>>>> Sep 22, 2020 3:56:17 PM org.jenkinsci.remoting.engine.WorkDirManager
>>>> initializeWorkDir INFO: Using /home/jenkins/.jenkins/remoting as a
>>>> remoting
>>>> work directory Sep 22, 2020 3:56:17 PM
>>>> org.jenkinsci.remoting.engine.WorkDirManager setupLogging INFO: Both error
>>>> and output logs will be printed to /home/jenkins/.jenkins/remoting
>>>> <===[JENKINS REMOTING CAPACITY]===>channel started Remoting version: 4.2
>>>> This is a Unix agent WARNING: An illegal reflective access operation has
>>>> occurred WARNING: Illegal reflective access by
>>>> jenkins.slaves.StandardOutputSwapper$ChannelSwapper to constructor
>>>> java.io.FileDescriptor(int) WARNING: Please consider reporting this to the
>>>> maintainers of jenkins.slaves.StandardOutputSwapper$ChannelSwapper
>>>> WARNING:
>>>> Use --illegal-access=warn to enable warnings of further illegal reflective
>>>> access operations WARNING: All illegal access operations will be denied in
>>>> a future release Evacuated stdout Agent successfully connected and online
>>>>
>>>>
>>>> [image: jenkins-ssh-agent-config.PNG]
>>>>
>>>> This is the full text in the "JVM Options" field for
>>>> jenkins-testing-agent-1 and 2:
>>>>
>>>> -Dhudson.slaves.WorkspaceList=-
>>>> -Dorg.apache.commons.jelly.tags.fmt.timeZone=America/Vancouver -Xmx64g
>>>> -Xms64g -XX:+AlwaysPreTouch -XX:+HeapDumpOnOutOfMemoryError
>>>> -XX:HeapDumpPath=/home/jenkins/.jenkins/support -XX:+UseG1GC
>>>> -XX:+UseStringDeduplication -XX:+ParallelRefProcEnabled
>>>> -XX:+DisableExplicitGC -XX:+UnlockDiagnosticVMOptions
>>>> -XX:+UnlockExperimentalVMOptions -verbose:gc
>>>> -Xlog:gc:/home/jenkins/.jenkins/support/gc-%t.log -XX:+PrintGC
>>>> -XX:+PrintGCDetails -XX:ErrorFile=/hs_err_%p.log -XX:+LogVMOutput
>>>> -XX:LogFile=/home/jenkins/.jenkins/support/jvm.log
>>>>
>>>> I am having intermittent catastrophic failures of these agent machines
>>>> during builds and am trying to properly configure java settings per
>>>> Cloudbees best practices, but I cannot seem to get off the ground here.
>>>> Another problem in my agents that's probably related is that the
>>>> agent-side
>>>> (remoting) logs are all zero bytes.
>>>>
>>>> Thanks for your help.
>>>>
>>>
--
You received this message because you are subscribed to the Google Groups
"Jenkins Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to jenkinsci-users+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/jenkinsci-users/8463b0ea-9df0-4c05-9bf4-0501296f2b9bn%40googlegroups.com.
