As a context, this need came up while analyzing a situation developed in one of the CloudBees' customer's Jenkins

Code changed in jenkins
User: Kohsuke Kawaguchi
Path:
src/main/java/hudson/remoting/Channel.java
src/test/java/hudson/remoting/ChannelTest.java
http://jenkins-ci.org/commit/remoting/522a022ae961d31b7b4346f90d04c3d08115e7f7
Log:
JENKINS-39150 expose diagnostics across all the channels

To be used by support-core, we need to be able to enumerate all active
channels. We do this via WeakHashMap so that references get
automatically garbage collected.

Unclosed channel will remain in memory forever, which also helps us find
those leaks.

Code changed in jenkins
User: Kohsuke Kawaguchi
Path:
src/main/java/hudson/remoting/Channel.java
src/main/java/hudson/remoting/Command.java
src/test/java/hudson/remoting/ChannelTest.java
http://jenkins-ci.org/commit/remoting/f9115111174fdac609ce16bb93fb1503b541a918
Log:
Merge pull request #122 from jenkinsci/JENKINS-39150

JENKINS-39150 expose diagnostics across all the channels

Compare: https://github.com/jenkinsci/remoting/compare/0c7df253043c...f9115111174f

Code changed in jenkins
User: Kohsuke Kawaguchi
Path:
pom.xml
src/main/java/com/cloudbees/jenkins/support/impl/RemotingDiagnostics.java
http://jenkins-ci.org/commit/support-core-plugin/d5b009c20f80839b49641d0419f6475e1cce513f
Log:
JENKINS-39150 report remoting diagnostics when it's available

Since this plugin cannot assume the version of core, access the method
in question via reflection (and also report the failure to find that
method, so that we have evidence either way.)

Code changed in jenkins
User: Kohsuke Kawaguchi
Path:
src/main/java/com/cloudbees/jenkins/support/impl/RemotingDiagnostics.java
http://jenkins-ci.org/commit/support-core-plugin/1f43ffb1e0cdf7de4ab1090aedf2b623f151e006
Log:
JENKINS-39150 report remoting diagnostics when it's available

Since this plugin cannot assume the version of core, access the method
in question via reflection (and also report the failure to find that
method, so that we have evidence either way.)

Code changed in jenkins
User: Oleg Nenashev
Path:
pom.xml
src/main/java/hudson/remoting/Channel.java
http://jenkins-ci.org/commit/remoting/9dc931703eb89ceb7608b88c0dd04da36f528a3b
Log:
JENKINS-39150 - API stabilization && compliance with the compatibility policy (#125)

• JENKINS-39150 - Restrict the newly introduced APIs in stable-2.x branch

• JENKINS-39150 - Fix error processing in the diagnostics dump API

• JENKINS-39150 - Fix Typos

• JENKINS-39150 - Even more diagnostics according to comments from @stephenc

• JENKINS-39150 - Statistic counters are long volatile now

Addresses comments from @oleg-nenashev and @rsandell

• JENKINS-39150 - Address comment from @oleg-nenashev about conflict with #109

• JENKINS-39150 - Fix another typo

Remoting fix has been integrated towards 2.62.3 and 3.1

Code changed in jenkins
User: Oleg Nenashev
Path:
pom.xml
http://jenkins-ci.org/commit/jenkins/7a948d399585d201c4132597aed5723a495acf69
Log:
Update remoting to 2.31 in the Jenkins core. (#2628)

The change introduces one serious bugfix (JENKINS-39596) and a bunch of various diagnostics improvements.

Bugfixes:

• JENKINS-39596(https://issues.jenkins-ci.org/browse/JENKINS-39596) -
  Jenkins URL in `hudson.remoting.Engine` was always `null` since `3.0`.
  It was causing connection failures of Jenkins JNLP agents when using Java Web Start.
  (PR #131(https://github.com/jenkinsci/remoting/pull/131))
• JENKINS-39617(https://issues.jenkins-ci.org/browse/JENKINS-39617) -
  `hudson.remoting.Engine` was failing to establish connection if one of the URLs parameter in parameters was malformed.
  (PR #131(https://github.com/jenkinsci/remoting/pull/131))

Improvements:

• JENKINS-39150(https://issues.jenkins-ci.org/browse/JENKINS-39150) -
  Add logic for dumping diagnostics across all the channels.
  (PR #122(https://github.com/jenkinsci/remoting/pull/122), PR #125(https://github.com/jenkinsci/remoting/pull/125))
• JENKINS-39543(https://issues.jenkins-ci.org/browse/JENKINS-39543) -
  Improve the caller/callee correlation diagnostics in thread dumps.
  (PR #119(https://github.com/jenkinsci/remoting/pull/119))
• JENKINS-39290(https://issues.jenkins-ci.org/browse/JENKINS-39290) -
  Add the `org.jenkinsci.remoting.nio.NioChannelHub.disabled` flag for disabling NIO (mostly for debugging purposes).
  (PR #123(https://github.com/jenkinsci/remoting/pull/123))
• JENKINS-38692(https://issues.jenkins-ci.org/browse/JENKINS-38692) -
  Add extra logging to help diagnosing `IOHub` Thread spikes.
  (PR #116(https://github.com/jenkinsci/remoting/pull/116))
• JENKINS-39289(https://issues.jenkins-ci.org/browse/JENKINS-39289) -
  When a proxy fails, report what caused the channel to go down.
  (PR #128(https://github.com/jenkinsci/remoting/pull/128))

The fix on the remoting side has been integrated towards 2.31

Code changed in jenkins
User: Kohsuke Kawaguchi
Path:
src/main/java/com/cloudbees/jenkins/support/impl/RemotingDiagnostics.java
http://jenkins-ci.org/commit/support-core-plugin/5f2f23de4e674a6ca22a1a0578b9c0ffa7a58c7a
Log:
Merge pull request #78 from jenkinsci/JENKINS-39150

[FIXED JENKINS-39150] report remoting diagnostics when it's available

Compare: https://github.com/jenkinsci/support-core-plugin/compare/c05e6e1026fa...5f2f23de4e67