agent

Previousstage Nextsecurity & authorization

Last updated 7 months ago

Was this helpful?

agent

references:

get information

API:
references:
sample scripts:

get all

get all agents including Jenkins master:
jenkins.model.Jenkins.instance.get().computers

jenkins.model.Jenkins.instance.computers.each { agent ->
  println "${agent.displayName} : ${agent.class} : ${agent.class.superclass}"
  println "     >> is master : ${jenkins.model.Jenkins.MasterComputer.isInstance(agent)}"
  println "     >> is cloud  : ${hudson.slaves.AbstractCloudComputer.isInstance(agent)} "
}

jenkins.model.Jenkins.instance.get().computers.each { agent ->
  println "${agent.displayName} : ${agent.class} : ${agent.class.superclass}"
  println "     >> is master : ${jenkins.model.Jenkins.MasterComputer.isInstance(agent)}"
  println "     >> is cloud  : ${hudson.slaves.AbstractCloudComputer.isInstance(agent)} "
}

`Computer` and `Node`

example for Computer Object

get description

jenkins.model.Jenkins.instance.getNode('<AGENT_NAME>').toComputer().description

get all info

import hudson.slaves.ComputerLauncher

String agentName = <AGENT_NAME>

jenkins.model.Jenkins.instance.computers.findAll { computer ->
  agentName == computer.name
}.each { computer ->
  String moreinfo = computer.online
                      ? "properties : ${computer.getSystemProperties().collect { k, v -> "$k=$v" }.join('\n\t\t\t>>> ')}"
                      : "      logs : ${computer.getLog()}"
  ComputerLauncher launcher = computer.node.launcher

  println """
    >> ${computer.displayName} :
                    class : ${computer.getClass()}
                    class : ${computer.class.superclass?.simpleName}
                  online? : ${computer.online}
              description : ${computer.description}
              connectTime : ${computer.connectTime} | ${new Date(computer.connectTime).format("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")}
    idleStartMilliseconds : ${computer.idleStartMilliseconds} | ${new Date(computer.idleStartMilliseconds).format("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'")}
       offlineCauseReason : ${computer.offlineCauseReason}
                 executor : ${computer.numExecutors} | ${computer.node.numExecutors}
                 launcher : ${launcher.host} | ${launcher.port} | ${launcher.credentialsId}
               ${moreinfo}
  """
}

result

     >> AGENT_NAME :
                     class : class hudson.slaves.SlaveComputer
                     class : Computer
                   online? : false
               description : marslo test agent offline
               connectTime : 1620478291102 | 2021-05-08T05:51:31.102Z
     idleStartMilliseconds : 1707980922716 | 2024-02-14T23:08:42.716Z
        offlineCauseReason : This agent is offline because Jenkins failed to launch the agent process on it.
                  executor : 1
                  launcher : 1.2.3.4 | sample.com | 22 | NEW_CREDENTIAL
                      logs : SSHLauncher{host='1.2.3.4', port=22, credentialsId='NEW_CREDENTIAL', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=30, maxNumRetries=5, retryWaitTime=30, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true}
 [05/08/21 05:51:31] [SSH] Opening SSH connection to 1.2.3.4:22.
 connect timed out
 SSH Connection failed with IOException: "connect timed out", retrying in 30 seconds. There are 5 more retries left.
 connect timed out
     ...

example for Node Object

import hudson.slaves.*

DumbSlave agent = jenkins.model.Jenkins.instance.getNode( 'AGEENT_NAME' )
ComputerLauncher launcher = agent.launcher

println """
     display name : ${agent.getDisplayName()}
        node name : ${agent.getNodeName()}
      description : ${agent.getNodeDescription()}
         executor : ${agent.getNumExecutors()}
     label string : ${agent.getLabelString()}
        node mode : ${agent.getMode()}
  hold off launch : ${agent.isHoldOffLaunchUntilSave()}
         launcher : ${launcher.host} | ${launcher.port} | ${launcher.credentialsId}
"""

result

   display name : AGEENT_NAME
      node name : AGEENT_NAME
    description : marslo test agent offline
       executor : 1
   label string :
      node mode : NORMAL
hold off launch : true
       launcher : 1.2.3.4 | sample.com | 22 | NEW_CREDENTIAL

setup hold off launch via: agent.holdOffLaunchUntilSave = true

node -> computer

String agent = 'AGEENT_NAME'

jenkins.model.Jenkins.instance.getNode(agent).toComputer().isOnline()
// or
hudson.model.Hudson.instance.getNode(agent).toComputer().isOnline()
// or
jenkins.model.Jenkins.instance.getNode(agent).computer.isOnline()

or get log

println jenkins.model.Jenkins.instance.getNode( 'AGEENT_NAME' ).toComputer().getLog()

// result
SSHLauncher{host='1.2.3.4', port=22, credentialsId='DevOpsSSHCredential', jvmOptions='', javaPath='', prefixStartSlaveCmd='', suffixStartSlaveCmd='', launchTimeoutSeconds=30, maxNumRetries=5, retryWaitTime=30, sshHostKeyVerificationStrategy=hudson.plugins.sshslaves.verifiers.NonVerifyingKeyVerificationStrategy, tcpNoDelay=true, trackCredentials=true}
[05/24/21 03:59:16] [SSH] Opening SSH connection to 1.2.3.4:22.
connect timed out
SSH Connection failed with IOException: "connect timed out", retrying in 30 seconds. There are 5 more retries left.

get projects tied to agent

[!NOTE|label:reference:]

import hudson.model.*
import jenkins.model.*
import hudson.slaves.*

String name = '<AGENT_NAME>'
Computer computer = jenkins.model.Jenkins.instance.getNode(name)?.computer ?: null
println computer.allExecutors.collect { it.currentWorkUnit?.work?.runId ?: '' }.join(', ') ?: ''

println computer.getAllExecutors().collect { it.getCurrentWorkUnit()?.work?.runId ?: '' }

println computer.allExecutors.collect { it.currentWorkUnit?.context?.task?.runId ?: '' }

get running job from label

[!TIP] solution:
hudson.model.Executor -> hudson.model.queue.WorkUnit -> org.jenkinsci.plugins.workflow.support.steps.ExecutorStepExecution$PlaceholderTask
hudson.model.Executor -> hudson.model.queue.WorkUnit -> hudson.model.queue.WorkUnitContext -> org.jenkinsci.plugins.workflow.support.steps.ExecutorStepExecution$PlaceholderTask

jenkins.model.Jenkins.instance.getNode(name)?.computer?.allExecutors.each {
  println it.currentWorkUnit.work.getClass()
  println '.................'
  println it.currentWorkUnit.work.label
  println it.currentWorkUnit.work.runId
  println '.................'
  println it.currentWorkUnit?.context?.task?.label
  println it.currentWorkUnit?.context?.task?.runId
  println '.................'
  println it.currentWorkUnit.work.getOwnerTask().getClass()
  println it.currentWorkUnit.work.getOwnerTask().getFullDisplayName()
  println '.................'
}
// result
class org.jenkinsci.plugins.workflow.support.steps.ExecutorStepExecution$PlaceholderTask
.................
AGENT_001
marslo/sandbox#6460
.................
AGENT_001
marslo/sandbox#6460
.................
class org.jenkinsci.plugins.workflow.job.WorkflowJob
marslo » sandbox
.................
Result: [Thread[Executor #0 for AGENT_001 : executing PlaceholderExecutable:ExecutorStepExecution.PlaceholderTask{runId=marslo/sandbox#6460,label=CI-WP-CD-RPI005,context=CpsStepContext[3:node]:Owner[marslo/sandbox/6460:marslo/sandbox #6460],cookie=null,auth=null},5,]]

get number of executor of agents

jenkins.model.Jenkins.instance.getNode(name)?.computer?.allExecutors?.size

import hudson.model.Computer.ListPossibleNames

println jenkins.model.Jenkins.instance
               .getNode( '<AGENT_NAME>' ).computer
               .getChannel().call(new ListPossibleNames())

println jenkins.model.Jenkins.instance
               .getNode( '<AGENT_NAME>' ).computer
               .getHostName()

println InetAddress.localHost.hostAddress

get agent credentialsId

[!NOTE|label:references:]

/**
 * @author marslo
 * @since 02/16/2024
 *
 * @result
 * | AGENT NAME         | NODE CREDENTIAL | COMPUTER CREDENTIIAL |
 * | ------------------ | --------------- | -------------------- |
 * | STAGING_TEST_01    | SSH_CREDENTIAL  | SSH_CREDENTIAL       |
 * | DEVELOPMENT_ENV_03 | SSH_CREDENTIAL  | SSH_CREDENTIAL       |
**/

List<String> title = [ 'AGENT NAME', 'NODE CREDENTIAL', 'COMPUTER CREDENTIIAL' ]
List<List<String>> agentCredentials = jenkins.model.Jenkins.instance.computers.findAll { computer ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(computer) &&
  computer?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher
}.collect { computer ->
  [ computer.name, computer.node.launcher?.credentialsId?.toString() ?: '', computer.launcher?.credentialsId?.toString() ?: '' ]
}

agentCredentials.add( 0, title )
agentCredentials.add( 0, agentCredentials.transpose().collect { column -> column.collect{ it.size() }.max() } )

agentCredentials = agentCredentials.withIndex().collect { raw, idx ->
  if ( idx ) raw.withIndex().collect { x, y -> x.toString().padRight(agentCredentials[0][y]) }
}.findAll()

String showTable ( List l ) {
  l.collect{ '| ' +  it.join(' | ' ) + ' |' }.join('\n')
}

println showTable( [ agentCredentials.head(), agentCredentials.head().collect { '-'*it.size() } ] )
println showTable( agentCredentials.tail() )

or simple output

/**
 * @author marslo
 * @since 02/16/2024
 *
 * @result
 * STAGING_TEST_01    | SSH_CREDENTIAL  | SSH_CREDENTIAL
 * DEVELOPMENT_ENV_03 | SSH_CREDENTIAL  | SSH_CREDENTIAL
**/

List<List<String>> agentCredentials = jenkins.model.Jenkins.instance.computers.findAll { computer ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(computer) &&
  computer?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher
}.collect { computer ->
  [ computer.name, computer.node.launcher?.credentialsId?.toString() ?: '', computer.launcher?.credentialsId?.toString() ?: '' ]
}

agentCredentials.add( 0, agentCredentials.transpose().collect { column -> column.collect{ it.size() }.max() } )
println agentCredentials.withIndex().collect { raw, idx ->
  if ( idx ) {
    raw.withIndex().collect { x, y -> "${x.padRight(agentCredentials[0][y])}" }.join(' | ')
  }
}.findAll().join('\n')

println "   AGENT".padRight(33) + "ONLINE".padRight(15) + "CREDENTIAL ID"

jenkins.model.Jenkins.instance.computers.findAll { computer ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(computer) &&
  computer?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher
}.each { computer ->
  println ">> ${computer.displayName.padRight(30)}" +
          "[${computer.online}]".padRight(15) +
          "${computer.node.launcher?.credentialsId?.toString() ?: ''} | ${computer.launcher?.credentialsId?.toString() ?: ''}"
}

"DONE"

println "   AGENT".padRight(33) + "ONLINE".padRight(15) + "CREDENTIAL ID"

jenkins.model.Jenkins.instance.nodes.findAll { node ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(node) &&
  node?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher
}.each { node ->
  println ">> ${node.displayName.padRight(30)}" +
          "[${node.computer.online}]".padRight(15) +
          "${node.launcher?.credentialsId?.toString() ?: ''} | ${node.computer.launcher?.credentialsId?.toString() ?: ''}"
}

"DONE"

get agent environment variable

import hudson.slaves.EnvironmentVariablesNodeProperty

jenkins.model.Jenkins.instance.slaves.each { agent ->
  List props = agent.nodeProperties.getAll(hudson.slaves.EnvironmentVariablesNodeProperty.class)
  if ( props ) {
    println """
       name : ${agent.name} :
      props : ${props.collect{ prop -> prop.envVars.collect { "${it.key} ~> ${it.value}" } }.flatten().join(', ')}
    """
  }
}

"DONE"

for ( slave in jenkins.model.Jenkins.instance.slaves ) {
  println( slave.name + ": " )
  def props = slave.nodeProperties.getAll(hudson.slaves.EnvironmentVariablesNodeProperty.class)
  for ( prop in props ) {
    for ( envvar in prop.envVars ) {
      println envvar.key + " -> " + envvar.value
    }
  }
}

get agent labels

println jenkins.model.Jenkins.instance.nodes.collect { agent ->
          "${agent.name} -> ${agent.getLabelString()}"
        }.join('\n')

function

def getLabel( String label ){
  jenkins.model.Jenkins.instance.nodes.find { it.getNodeName().toString().equals(label) }.getLabelString()
}

def getLabel( String label ){
  for ( node in jenkins.model.Jenkins.instance.nodes ) {
    if ( node.getNodeName().toString().equals(label) ) {
      return node.getLabelString()
    }
  }
}

def nodes = jenkins.model.Jenkins.get().computers
                   .findAll{ it.node.labelString.contains(label) }
                   .collect{ it.node.selfLabel.name }

@NonCPS
def hostNames(label) {
  def nodes = []
  jenkins.model.Jenkins.get.computers.each { c ->
    if (c.node.labelString.contains(label)) {
      nodes.add(c.node.selfLabel.name)
    }
  }
  return nodes
}

jenkins.model.Jenkins.instance.getLabel('my-label').getNodes().collect{ it.getNodeName() }

cloud agents

check how many cloud agent running

println jenkins.model.Jenkins.instance.getNodes().findAll {
  [ 'AbstractCloudSlave', 'AbstractCloudComputer' ].contains(it.class.superclass?.simpleName)
}.size()

KubernetesComputer

[!NOTE] references:
io.fabric8.kubernetes.api.model.Container

import org.csanchez.jenkins.plugins.kubernetes.KubernetesComputer
import io.fabric8.kubernetes.api.model.Container
import io.fabric8.kubernetes.api.model.EnvVar
import io.fabric8.kubernetes.api.model.VolumeMount

String sep    = ' ' * 16
String subsep = ' ' * 20

jenkins.model.Jenkins.instance.computers.findAll{ it instanceof KubernetesComputer && it.isOnline()}.each { computer ->
  println """
         name : ${computer.getDisplayName()}
       images : ${computer.getContainers().collect{ it.image }.join(', ')}
           os : ${computer.getOSDescription()}
  isJnlpAgent : ${computer.isJnlpAgent()}
         jobs : ${computer.allExecutors.collect { it.currentWorkUnit?.work?.runId ?: '' }.join(', ') ?: ''}
          env : ${computer.containers.collect{ it.getEnv() }.flatten().collect{ "${it.name} : ${it.value}" }.join( '\n' + sep )}
    resources : limits :
                    ${computer.containers.collect{ it.getResources().getLimits() }?.first().collect{ "${it.key} : ${it.value}"}.join( '\n' + subsep ) ?: ''}
                requests :
                    ${computer.containers.collect{ it.getResources().getRequests() }?.first().collect{ "${it.key} : ${it.value}"}.join( '\n' + subsep ) ?: ''}
       volume : ${computer.containers.collect { it.getVolumeMounts() }.flatten().collect{ "${it.name} : ${it.mountPath}" }.join( '\n' + sep )}
     commands : ${computer.containers.collect{ it.getCommand() }.join(', ')}
         agrs : ${computer.containers.collect{ it.getArgs() }.join(', ')}
   workingDir : ${computer.containers.collect{ it.getWorkingDir() }.join()}
      message : ${computer.containers.collect{ it.getTerminationMessagePath()}.join()}
  isLaunching : ${computer.isLaunching()}
     isOnline : ${computer.isOnline()}
  """
}

result

       name : jenkins-sample-job-381-fcql9-j2mp9
     images : artifactory.domain.com/docker/jnlp:2.0.2-py38-bionic
         os : Unix
isJnlpAgent : true
       jobs : sample-job#381
        env : JENKINS_SECRET : 43406803cb55dc7457242e08232c9e762cfb68e08157485e31d2c1fff4624d72
              JENKINS_TUNNEL : 10.69.78.73:30380
              JENKINS_AGENT_NAME : jenkins-sample-job-381-fcql9-j2mp9
              JENKINS_NAME : jenkins-sample-job-381-fcql9-j2mp9
              JENKINS_AGENT_WORKDIR : /home/devops
              JENKINS_URL : https://jenkins.domain.com/
  resources : limits :
                  cpu : 1
                  ephemeral-storage : 500Mi
                  memory : 1Gi
              requests :
                  cpu : 500m
                  ephemeral-storage : 50Mi
                  memory : 512Mi
     volume : workspace-volume : /home/devops
              default-token-m6bqf : /var/run/secrets/kubernetes.io/serviceaccount
   commands : []
       agrs : []
 workingDir : /home/devops
    message : /dev/termination-log
isLaunching : false
   isOnline : true

executor

reference:

[!NOTE|label:getParentExecutable]

@CheckForNull default Queue.Executable getParentExecutable()

An umbrella executable (such as a Run) of which this is one part. Some invariants:
  - `getParent().getOwnerTask() == getParent()` || `getParentExecutable().getParent() == getParent().getOwnerTask()`
  - `getParent().getOwnerExecutable() == null`  || `getParentExecutable() == getParent().getOwnerExecutable()`

Returns:
   a distinct executable (never this, unlike the default of SubTask.getOwnerTask()!); or null if this executable was already at top level

See Also:
  SubTask.getOwnerExecutable()

basic usage

List<List<hudson.model.Executor>> executors = jenkins.model.Jenkins.instance.computers.collect {c -> c.executors}
println executors.collect{ e -> e.collect{ it.getClass() } }

// Result:
// [[class hudson.model.Executor, class hudson.model.Executor], [class hudson.model.Executor]]

import jenkins.model.Jenkins

int active_builds      = 0
int inactive_executors = 0

jenkins.model.Jenkins.instance.slaves.findAll { agent ->
  ! agent.computer.isOffline()
}.each { agent ->
  def executors = agent.computer.executors
  executors.each { executor ->
    if ( executor.isBusy() ) {
      active_builds++
    } else {
      inactive_executors++
    }
  }
}

println """
           Queue : ${jenkins.model.Jenkins.instance.queue.items.size()}
          Active : ${active_builds}
  Free executors : ${inactive_executors}
"""

result

           Queue : 0
          Active : 10
  Free executors : 100

features


jenkins.model.Jenkins.instance
                     .computers.collect { c -> c.executors }
                     .collectMany { e -> e.findAll{ it.isBusy() } }
                     .each{ e ->
                        println '\n>> e.owenr:'
                        println "\te.owner : ${e.owner}"
                        println "\te.owner.countBusy : ${e.owner.countBusy()}"
                        println "\te.owner.countExecutors : ${e.owner.countExecutors()}"
                        println "\te.owner.log :   ${e.owner.log.split('\n').join('\n\t\t\t')}"

                        println '\n>> e.status:'
                        println "\te.isBusy() : ${e.isBusy()}"
                        println "\te.isIdle() : ${e.isIdle()}"
                        println "\te.isLikelyStuck() : ${e.isLikelyStuck()}"
                        println "\te.isParking() : ${e.isParking()}"

                        println '\n>> e.currentWorkUnit.work:'
                        println "\tfullDisplayName : ${e.currentWorkUnit.work.fullDisplayName}"
                        println "\trunId: ${e.currentWorkUnit.work.runId}"
                        println "\tlabel: ${e.currentWorkUnit.work.label}"
                        println "\townerTask : ${e.currentWorkUnit.work.ownerTask}"
                        println "\tgetResourceList() : ${e.currentWorkUnit.work.getResourceList()}"
                        println "\tisBuildBlocked() : ${e.currentWorkUnit.work.isBuildBlocked()}"
                        println "\tisConcurrentBuild() : ${e.currentWorkUnit.work.isConcurrentBuild()}"
                        println "\tisContinued() : ${e.currentWorkUnit.work.isContinued()}"

                        println "\n>> e.currentExecutable:"
                        println "\turl : ${e.currentExecutable?.url}"
                        println "\tnumber : ${e.currentExecutable?.number}"
                        println "\testimatedDuration : ${e.currentExecutable?.estimatedDuration}"
                        println "\tfullDisplayName : ${e.currentExecutable?.fullDisplayName}"

                        println "\n>> e.currentExecutable.parentExecutable:"
                        println "\tcurrentExecutable.parentExecutable: ${e.currentExecutable.parentExecutable.getClass()}"

                        println "\n>> e.currentWorkUnit.work.ownerTask:"
                        println "\townerTask : ${e.currentWorkUnit.work.ownerTask.getClass()}"
                     }

result

>> e.owenr:
  e.owner : KubernetesComputer name: jenkins-yaml-31-51jcr-wclf1 agent: KubernetesSlave name: jenkins-yaml-31-51jcr-wclf1
  e.owner.countBusy : 1
  e.owner.countExecutors : 1
  e.owner.log :   Inbound agent connected from 10.244.13.0/10.244.13.0:33584
                  Remoting version: 4.13
                  Launcher: KubernetesLauncher
                  Communication Protocol: JNLP4-connect
                  This is a Unix agent
                  Agent successfully connected and online

>> e.status:
  e.isBusy() : true
  e.isIdle() : false
  e.isLikelyStuck() : false
  e.isParking() : false

>> e.currentWorkUnit.work:
  fullDisplayName : yaml #31 (show info)
  runId: yaml#31
  label: jenkins-yaml-31-51jcr-wclf1
  ownerTask : org.jenkinsci.plugins.workflow.job.WorkflowJob@775876ce[yaml]
  getResourceList() : {}
  isBuildBlocked() : false
  isConcurrentBuild() : false
  isContinued() : true

>> e.currentExecutable:
  url : job/yaml/31/
  number : 31
  estimatedDuration : 17227
  fullDisplayName : yaml #31 (show info)

>> e.currentExecutable.parentExecutable:
  currentExecutable.parentExecutable: class org.jenkinsci.plugins.workflow.job.WorkflowRun

>> e.currentWorkUnit.work.ownerTask:
  ownerTask : class org.jenkinsci.plugins.workflow.job.WorkflowJob

stop all running builds via WorkflowRun

[!NOTE]
using WorkflowRun.finish might cause issue : https://stackoverflow.com/q/75651552/2940319

List<List<hudson.model.Executor>> executors = jenkins.model.Jenkins.instance.computers.collect { c -> c.executors }
List<hudson.model.Executor> busyExecutors   = jenkins.model.Jenkins.instance.computers.collect { c -> c.executors }.collectMany { it.findAll{ it.isBusy() } }

busyExecutors.each {
  org.jenkinsci.plugins.workflow.job.WorkflowRun run = it?.currentExecutable?.parentExecutable
  run.setDescription( '<b>aborted by Jenkins restart</b><br>' )
  run.finish( hudson.model.Result.NOT_BUILT, new java.io.IOException( "aborted by Jenkins restart" ) )
}

force interrupt executors

List<List<hudson.model.Executor>> executors = jenkins.model.Jenkins.instance.computers.collect { c -> c.executors }
List<hudson.model.Executor> busyExecutors   = jenkins.model.Jenkins.instance.computers.collect { c -> c.executors }.collectMany { it.findAll{ it.isBusy() } }
busyExecutors.each { it.interrupt() }

// or simply in one line
jenkins.model.Jenkins.instance
                     .computers.collect { c -> c.executors }
                     .collectMany { it.findAll{ it.isBusy() } }
                     .each { it.interrupt() }

[!NOTE|label:basic concept] Computer -> Executor -> ExecutorStepExecution$PlaceholderTask$PlaceholderExecutable -> WorkflowRun

jenkins.model.Jenkins.instance
                     .computers.collect { c -> c.executors }                 // all executors
                     .collectMany { it.findAll{ it.isBusy() } }              // running executors
                     .collectMany {[
                        it?.getClass(),                                      // Executor
                        it?.currentExecutable?.getClass(),                   // org.jenkinsci.plugins.workflow.support.steps.ExecutorStepExecution$PlaceholderTask$PlaceholderExecutable
                        it?.currentExecutable?.parentExecutable?.getClass()  // org.jenkinsci.plugins.workflow.job.WorkflowRun
                     ]}

to `WorkUnit` and `SubTask` ( `ExecutorStepExecution.PlaceholderTask` )

jenkins.model.Jenkins.instance.computers.findAll { computer ->
  '<agentName>' == computer.name
}.collect { it.executors }
 .flatten()
 .each { e ->
   println e                      // class hudson.model.Executor
   println e.currentWorkUnit      // hudson.model.queue.WorkUnit
   println e.currentWorkUnit.work // org.jenkinsci.plugins.workflow.support.steps.ExecutorStepExecution$PlaceholderTask
 }

result

e                              :  Thread[Executor #0 for jenkins-sandbox-sample-11998-r16jc-nj9fc : executing PlaceholderExecutable:ExecutorStepExecution.PlaceholderTask{runId=sandbox/sample#11998,label=jenkins-sandbox-sample-11998,context=CpsStepContext[10:node]:Owner[sandbox/sample/11998:sandbox/sample #11998],cookie=null,auth=null},5,]
e.currentWorkUnit              :  hudson.model.queue.WorkUnit@5e2236a4[work=part of sandbox » sample #11998]
e.currentWorkUnit.work         :  ExecutorStepExecution.PlaceholderTask{runId=sandbox/sample#11998,label=jenkins-sandbox-sample-11998-r16jc-nj9fc,context=CpsStepContext[10:node]:Owner[sandbox/sample/11998:sandbox/sample #11998],cookie=80f25325-1b41-48fc-89aa-5b81e8288c5f,auth=null}

to `Computer`

jenkins.model.Jenkins.instance.computers.findAll { computer ->
  '<agentName>' == computer.name
}.collect { it.executors }
 .flatten()
 .each { e ->
   println e                      // class hudson.model.Executor
   println e.owner                // class org.csanchez.jenkins.plugins.kubernetes.KubernetesComputer
 }

result

e                              :  Thread[Executor #0 for jenkins-sandbox-sample-11998-r16jc-nj9fc : executing PlaceholderExecutable:ExecutorStepExecution.PlaceholderTask{runId=sandbox/sample#11998,label=jenkins-sandbox-sample-11998,context=CpsStepContext[10:node]:Owner[sandbox/sample/11998:sandbox/sample #11998],cookie=null,auth=null},5,]
owner                          :  KubernetesComputer name: jenkins-sandbox-sample-11998-r16jc-nj9fc agent: null

api:

[!NOTE|label:references:]
scripts:

useful libs:
import jenkins.model.*
import hudson.slaves.*
import hudson.slaves.NodePropertyDescriptor
import hudson.plugins.sshslaves.*
import hudson.plugins.sshslaves.verifiers.*
import hudson.model.*
import hudson.model.Node
import hudson.model.Queue
import hudson.model.queue.CauseOfBlockage
import hudson.slaves.EnvironmentVariablesNodeProperty.Entry
import java.util.ArrayList
import com.synopsys.arc.jenkinsci.plugins.jobrestrictions.nodes.JobRestrictionProperty
import com.synopsys.arc.jenkinsci.plugins.jobrestrictions.Messages
import com.synopsys.arc.jenkinsci.plugins.jobrestrictions.restrictions.JobRestriction
import com.synopsys.arc.jenkinsci.plugins.jobrestrictions.restrictions.JobRestrictionBlockageCause
import hudson.Extension
import hudson.slaves.NodeProperty
import org.kohsuke.stapler.DataBoundConstructor
SSH host verification strategy:
// Known hosts file Verification Strategy
new KnownHostsFileKeyVerificationStrategy()
// Manually provided key Verification Strategy
new ManuallyProvidedKeyVerificationStrategy("<your-key-here>")
// Manually trusted key Verification Strategy
new ManuallyTrustedKeyVerificationStrategy(false /*requires initial manual trust*/)
// Non verifying Verification Strategy
new NonVerifyingKeyVerificationStrategy()

import hudson.model.*
import jenkins.model.*
import hudson.slaves.*
import hudson.slaves.EnvironmentVariablesNodeProperty.Entry
import hudson.plugins.sshslaves.verifiers.*

// Pick one of the strategies from the comments below this line
// SshHostKeyVerificationStrategy hostKeyVerificationStrategy = new KnownHostsFileKeyVerificationStrategy()
//    = new KnownHostsFileKeyVerificationStrategy(                                         ) // Known hosts file Verification Strategy
//    = new ManuallyProvidedKeyVerificationStrategy("<your-key-here>"                      ) // Manually provided key Verification Strategy
//    = new ManuallyTrustedKeyVerificationStrategy(false /*requires initial manual trust*/ ) // Manually trusted key Verification Strategy
//    = new NonVerifyingKeyVerificationStrategy(                                           ) // Non verifying Verification Strategy

// define a "Launch method": "Launch agents via SSH"
ComputerLauncher launcher = new hudson.plugins.sshslaves.SSHLauncher(
        "1.2.3.4",                                 // Host
        22,                                        // Port
        "MyCredentials",                           // Credentials
        (String)null,                              // JVM Options
        (String)null,                              // JavaPath
        (String)null,                              // Prefix Start Agent Command
        (String)null,                              // Suffix Start Agent Command
        (Integer)null,                             // Connection Timeout in Seconds
        (Integer)null,                             // Maximum Number of Retries
        (Integer)null,                             // The number of seconds to wait between retries
        new NonVerifyingKeyVerificationStrategy()  // Host Key Verification Strategy
)

// define a "Permanent Agent"
Slave agent             = new DumbSlave( "AGEENT_NAME", "/home/devops", launcher )
agent.nodeDescription   = '.. agent description ..'
agent.numExecutors      = 1
agent.labelString       = ''
agent.mode              = Node.Mode.NORMAL
agent.retentionStrategy = new RetentionStrategy.Always()

List<Entry> env         = new ArrayList<Entry>();
env.add(new Entry("key1","value1"))
env.add(new Entry("key2","value2"))
EnvironmentVariablesNodeProperty envPro = new EnvironmentVariablesNodeProperty(env);

agent.getNodeProperties().add(envPro)

// create a "Permanent Agent"
jenkins.model.Jenkins.instance.addNode(agent)

return "Node has been created successfully."

import hudson.model.*
import jenkins.model.*
import hudson.slaves.*
import hudson.plugins.sshslaves.verifiers.*
import hudson.slaves.EnvironmentVariablesNodeProperty.Entry

String name        = 'AGEENT_NAME'
String description = 'marslo test agent'
String rootDir     = '/home/marslo'
String nodeLabel   = ''
String ip          = '1.2.3.4'
String credential  = 'MyCredential'
Map envVars        = [
  'key1' : 'value1',
  'key2' : 'value2'
]
SshHostKeyVerificationStrategy hostKeyVerificationStrategy = new NonVerifyingKeyVerificationStrategy()

List<Entry> env = new ArrayList<Entry>();
envVars.each { k, v -> env.add(new Entry(k, v)) }
EnvironmentVariablesNodeProperty envPro = new EnvironmentVariablesNodeProperty(env);

Slave agent = new DumbSlave(
  name,
  description,
  rootDir,
  "1",
  Node.Mode.NORMAL,
  nodeLabel,
  new hudson.plugins.sshslaves.SSHLauncher(
    ip,                          // Host
    22,                          // Port
    credential,                  // Credentials
    (String)null,                // JVM Options
    (String)null,                // JavaPath
    (String)null,                // Prefix Start Agent Command
    (String)null,                // Suffix Start Agent Command
    (Integer)null,               // Connection Timeout in Seconds
    (Integer)null,               // Maximum Number of Retries
    (Integer)null,               // The number of seconds to wait between retries
    hostKeyVerificationStrategy  // Host Key Verification Strategy
  ) ,
  new RetentionStrategy.Always(),
  new LinkedList()
)

agent.getNodeProperties().add(envPro)
jenkins.model.Jenkins.instance.addNode(agent)

update agent label

[!NOTE|label:references:]

def updateLabel( String agent, String label ) {
  def node = jenkins.model.Jenkins.instance.getNode( agent )
  if ( node ) {
    node.setLabelString( label )
    node.save()
  }
}

update agent credentialsId

[!NOTE|label:references:]

import jenkins.model.Jenkins
import hudson.plugins.sshslaves.SSHLauncher
import hudson.slaves.ComputerLauncher

String newCredId = 'NEW_CREDENTIAL'

jenkins.model.Jenkins.instance.nodes.findAll { node ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(node) &&
  node?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher
}.each { node ->
  println ">> ${node.name} update <<"
  ComputerLauncher launcher = node.launcher
  SSHLauncher newLauncher = new SSHLauncher( launcher.host,
                                             launcher.port,
                                             newCredId,
                                             launcher.jvmOptions,
                                             launcher.javaPath,
                                             launcher.prefixStartSlaveCmd,
                                             launcher.suffixStartSlaveCmd,
                                             launcher.launchTimeoutSeconds,
                                             launcher.maxNumRetries,
                                             launcher.retryWaitTime,
                                             launcher.sshHostKeyVerificationStrategy
                                           )
  node.setLauncher( newLauncher )
  node.save()
  node.computer.setNode( node )

  // restart agent
  if ( node.computer.isOnline() && node.computer.countBusy() == 0 ) {
    println ">> ${node.name} disconnect <<"
    String message = 'disconnect due to credential update'
    node.computer.setTemporarilyOffline( true, new hudson.slaves.OfflineCause.ByCLI(message) )
    node.computer.disconnect( new hudson.slaves.OfflineCause.UserCause(User.current(), message ) )
    node.computer.doChangeOfflineCause( message )
    println '\t.. computer.getOfflineCause: ' + node.computer.getOfflineCause();
  }
  Thread.sleep( 5*1000 )
  if ( node.computer.isOffline() ) {
    println ">> ${node.name} reconnect <<"
    node.getComputer().connect( true )
    node.computer.setTemporarilyOffline( false, null )
  }
}

or simply

import jenkins.model.Jenkins
import hudson.plugins.sshslaves.SSHLauncher
import hudson.slaves.ComputerLauncher

String newCredId = 'NEW_CREDENTIAL'

jenkins.model.Jenkins.instance.nodes.findAll { node ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(node) &&
  node?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher
}.each { node ->
  println ">> ${node.name} update <<"
  ComputerLauncher launcher = node.launcher
  SSHLauncher newLauncher = new SSHLauncher( launcher.host, launcher.port, newCredId )
  newLauncher.sshHostKeyVerificationStrategy = launcher.sshHostKeyVerificationStrategy
  node.setLauncher( newLauncher )
  node.save()
  node.computer.setNode( node )
}

// restart agent
if ( node.computer.isOnline() && node.computer.countBusy() == 0 ) {
  println ">> ${node.name} disconnect <<"
  String message = 'disconnect due to credential update'
  node.computer.setTemporarilyOffline( true, new hudson.slaves.OfflineCause.ByCLI(message) )
  node.computer.disconnect( new hudson.slaves.OfflineCause.UserCause(User.current(), message ) )
  node.computer.doChangeOfflineCause( message )
  println '\t.. computer.getOfflineCause: ' + node.computer.getOfflineCause();
}
Thread.sleep( 5*1000 )
if ( node.computer.isOffline() ) {
  println ">> ${node.name} reconnect <<"
  node.getComputer().connect( true )
  node.computer.setTemporarilyOffline( false, null )
}

by Jenkins.instance.addNode

import hudson.slaves.*
import hudson.model.Node.Mode
import jenkins.model.Jenkins
import hudson.plugins.sshslaves.SSHLauncher

String newCredId = 'NEW_CREDENTIAL'
String nodeName  = AGENT_NAME

jenkins.model.Jenkins.instance.nodes.findAll { node ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(node) &&
  node?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher &&
  nodeName == node.name
}.each { node ->
  ComputerLauncher launcher = node.launcher
  SSHLauncher newLauncher = new SSHLauncher( launcher.host,
                                             launcher.port,
                                             newCredId,
                                             launcher.jvmOptions,
                                             launcher.javaPath,
                                             launcher.prefixStartSlaveCmd,
                                             launcher.suffixStartSlaveCmd,
                                             launcher.launchTimeoutSeconds,
                                             launcher.maxNumRetries,
                                             launcher.retryWaitTime,
                                             launcher.sshHostKeyVerificationStrategy
                                           )
  DumbSlave agent = new DumbSlave( node.name, node.remoteFS, newLauncher )
  agent.nodeDescription   = node.nodeDescription
  agent.numExecutors      = node.numExecutors
  agent.labelString       = node.labelString
  agent.mode              = node.mode
  agent.retentionStrategy = node.retentionStrategy
  node.computer.doDoDelete()
  Thread.sleep( 5*1000 )
  jenkins.model.Jenkins.instance.addNode( agent )

  // restart agent
  if ( node.computer.isOnline() && node.computer.countBusy() == 0 ) {
    println ">> ${node.name} disconnect <<"
    String message = 'disconnect due to credential update'
    node.computer.setTemporarilyOffline( true, new hudson.slaves.OfflineCause.ByCLI(message) )
    node.computer.disconnect( new hudson.slaves.OfflineCause.UserCause(User.current(), message ) )
    node.computer.doChangeOfflineCause( message )
    println '\t.. computer.getOfflineCause: ' + node.computer.getOfflineCause();
  }
  Thread.sleep( 5*1000 )
  if ( node.computer.isOffline() ) {
    println ">> ${node.name} re-connect <<"
    node.getComputer().connect( true )
    node.computer.setTemporarilyOffline( false, null )
  }
}

universal agent update

/**
 * @author marslo
 * @since 02/14/2024
**/

import hudson.slaves.*
import hudson.model.Node.Mode
import jenkins.model.Jenkins
import hudson.plugins.sshslaves.SSHLauncher

Map<String, Object> newInfo = [
        credId : 'NEW_CREDENTIAL' ,
          name : ''               ,
         label : ''               ,
   description : ''               ,
      hostname : ''               ,
  numExecutors : 1                ,
          port : 22
]

jenkins.model.Jenkins.instance.nodes.findAll { node ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(node) &&
  node?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher
}.each { node ->
  println ">> ${node.name} update <<"
  ComputerLauncher launcher = node.launcher
  SSHLauncher newLauncher = new SSHLauncher( newInfo.get('hostname') ?: launcher.host,
                                             newInfo.get('port')     ?: launcher.port,
                                             newInfo.get('credId')   ?: launcher.credentialsId,
                                             launcher.jvmOptions,
                                             launcher.javaPath,
                                             launcher.prefixStartSlaveCmd,
                                             launcher.suffixStartSlaveCmd,
                                             launcher.launchTimeoutSeconds,
                                             launcher.maxNumRetries,
                                             launcher.retryWaitTime,
                                             launcher.sshHostKeyVerificationStrategy
                                           )
  node.nodeDescription   = newInfo.get('description')  ?: node.nodeDescription
  node.numExecutors      = newInfo.get('numExecutors') ?: node.numExecutors
  node.labelString       = newInfo.get('label')        ?: node.labelString
  node.mode              = node.mode
  node.retentionStrategy = node.retentionStrategy
  node.setLauncher( newLauncher )
  node.save()
  node.computer.setNode( node )

  // disconnect agent
  if ( node.computer.isOnline() && node.computer.countBusy() == 0 ) {
    println ">> ${node.name} disconnect <<"
    String message = 'disconnect due to credential update'
    node.computer.setTemporarilyOffline( true, new hudson.slaves.OfflineCause.ByCLI(message) )
    node.computer.disconnect( new hudson.slaves.OfflineCause.UserCause(User.current(), message ) )
    node.computer.doChangeOfflineCause( message )
    println '\t.. computer.getOfflineCause: ' + node.computer.getOfflineCause();
  }

  // connect agent
  Thread.sleep( 5*1000 )
  if ( node.computer.isOffline() ) {
    println ">> ${node.name} connect <<"
    node.getComputer().connect( true )
    node.computer.setTemporarilyOffline( false, null )
  }

  println ">> ${node.name} DONE <<"
}

"DONE"

disconnect agent

reconnect:
agent.computer.connect( true )
jenkins.model.Jenkins.instance.getNode( name ).computer.connect( true )
disconnect:
agent.computer.doDoDisconnect( 'messasge' )
agent.computer.disconnect( new hudson.slaves.OfflineCause.UserCause(User.current(), 'message') )
agent.computer.disconnect( new hudson.slaves.OfflineCause.ByCLI('message') )
reference:
API:

import jenkins.model.Jenkins
import hudson.plugins.sshslaves.SSHLauncher
import hudson.slaves.ComputerLauncher
import hudson.slaves.OfflineCause

String newCredId = 'NEW_CREDENTIAL'
String nodeName  = 'AGENT_NAME'

jenkins.model.Jenkins.instance.nodes.findAll { node ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(node) &&
  node?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher &&
  nodeName == node.name
}.each { node ->
  if ( node.computer.isOnline() && node.computer.countBusy() == 0 ) {
    println ">> ${node.name} disconnect <<"
    String message = 'disconnect due to ...'
    node.computer.setTemporarilyOffline( true, new hudson.slaves.OfflineCause.ByCLI(message) )
    node.computer.disconnect( new OfflineCause.UserCause(User.current(), message) )
    node.computer.doChangeOfflineCause( message )
    println '\t.. computer.getOfflineCause: ' + node.computer.getOfflineCause();
  }
}

legacy version

import hudson.slaves.*

String name = 'AGEENT_NAME'
String cause = "disconnet the agent automatically via ${env.BUILD_URL}"

DumbSlave agent = jenkins.model.Jenkins.instance.getNode( name )

if ( agent
     && ! ['AbstractCloudComputer', 'AbstractCloudSlave'].contains(agent.computer?.class.superclass?.simpleName)
     && ! (agent.computer instanceof jenkins.model.Jenkins.MasterComputer)
   ) {
    Boolean online = agent.computer.isOnline()
    Boolean busy = agent.computer.countBusy() != 0
    if( online && !busy ) {
      agent.computer.disconnect( new OfflineCause.ChannelTermination(new UnsupportedOperationException(cause)) )
    }
}

temporarily offline agent

offline agent is normally for workspace cleanup
reference:
bring node online
computer.setTemporarilyOffline( false, null )

[!NOTE|label:references:]

import hudson.slaves.OfflineCause

// offline
node.computer.setTemporarilyOffline( true, new hudson.slaves.OfflineCause.ByCLI("disk cleanup on slave") )
// online
node.computer.setTemporarilyOffline( false, null )
// or online
node.computer.cliOnline()

import jenkins.model.Jenkins
import hudson.plugins.sshslaves.SSHLauncher
import hudson.slaves.ComputerLauncher

String nodeName = <AGENT_NAME>

jenkins.model.Jenkins.instance.nodes.findAll { node ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(node) &&
  node?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher &&
  nodeName == node.name
}.each { node ->
  if ( node.computer.isOnline() && node.computer.countBusy() == 0 ) {
    println ">> ${node.name} offline <<"
    String message = 'disconnect due to update credential'
    node.computer.setTemporarilyOffline(true, new hudson.slaves.OfflineCause.ByCLI( message ))
    node.computer.doChangeOfflineCause( message )
    println '\t.. computer.getOfflineCause: ' + node.computer.getOfflineCause();
  }

  if ( ! node.computer.isOnline() ) {
    sleep 10
    println ">> ${node.name} re-online <<"
    node.computer.cliOnline()
  }
}

legacy version

import hudson.slaves.*

String name  = 'AGEENT_NAME'
String cause = "temporary offline for the agent workspace cleanup"
DumbSlave agent = jenkins.model.Jenkins.instance.getNode( name )

if ( agent
     && ! ['AbstractCloudComputer', 'AbstractCloudSlave'].contains(agent.computer?.class.superclass?.simpleName)
     && ! (agent.computer instanceof jenkins.model.Jenkins.MasterComputer)
 ) {
  Boolean online = agent.computer.isOnline()
  Boolean busy = agent.computer.countBusy() != 0

  if( online && !busy ) {
    agent.computer.setTemporarilyOffline( true,
                                          new hudson.slaves.OfflineCause.ByCLI("disk cleanup on slave")
                                        )
  }
}

restart agent

[!NOTE|label:references:]

import jenkins.model.Jenkins
import hudson.plugins.sshslaves.SSHLauncher
import hudson.slaves.ComputerLauncher
import hudson.slaves.OfflineCause

String nodeName = '<AGENT_NAME>'

jenkins.model.Jenkins.instance.nodes.findAll { node ->
  ! jenkins.model.Jenkins.MasterComputer.isInstance(node) &&
  node?.launcher instanceof hudson.plugins.sshslaves.SSHLauncher &&
  nodeName == node.name
}.each { node ->
  if ( node.computer.isOnline() && node.computer.countBusy() == 0 ) {
    println ">> ${node.name} disconnect <<"
    String message = 'disconnect due to ...'
    node.computer.setTemporarilyOffline( true, new hudson.slaves.OfflineCause.ByCLI(message) )
    node.computer.disconnect( new OfflineCause.UserCause(User.current(), message ) )
    node.computer.doChangeOfflineCause( message )
    println '\t.. computer.getOfflineCause: ' + node.computer.getOfflineCause();
  }

  if ( node.computer.isOffline() ) {
    sleep 10
    println ">> ${node.name} re-connect <<"
    node.getComputer().connect( true )
    node.getComputer().cliOnline()
  }
}

delete agent

references:

def isAgentExists( String name ) {
  jenkins.model.Jenkins.instance.getNodes().any { name == it.computer?.name }
}

def removeAgent( String name ) {
  Boolean deleted = false
  DumbSlave agent = jenkins.model.Jenkins.instance.getNode( name )

  if ( agent
       && ! AbstractCloudComputer.isInstance( agent.computer )
       && ! AbstractCloudSlave.isInstance( agent.computer )
       && ! ( agent.computer instanceof jenkins.model.Jenkins.MasterComputer )
  ) {
    Boolean online = agent.computer.isOnline()
    Boolean busy   = agent.computer.countBusy() != 0

    if ( !busy ) {
      println """
        "${online ? ' offline and' : ''} remove agent ${name} :"
           display name : ${agent.getDisplayName()}
            description : ${agent.getNodeDescription()}
               executor : ${agent.getNumExecutors()}
              node mode : ${agent.getMode()}
                online? : ${online}
                  busy? : ${busy}
         offline cause? : ${agent.computer.getOfflineCause()}
      """
      if ( online ) {
        agent.computer.setTemporarilyOffline( true,
                                              new hudson.slaves.OfflineCause.ByCLI('offline due to agent will be removed automatically')
        )
        Thread.sleep( 5*1000 )
      }
      agent.computer.doDoDelete()
      deleted = ! isAgentExists( name )
      println( "INFO: agent ${name} ${deleted ? 'has been successfully removed' : 'failed been removed'} from ${env.JENKINS_URL}computer")
    } else {
      println("WARN: the agent ${name} cannot be removed due to project is tie to it" )
    }
  } else {
    println('WARN: cloud agent or Jenkins master cannot be removed!' )
  }

  return deleted
}

references:

import hudson.node_monitors.*
import hudson.slaves.*
import java.util.concurrent.*
import javax.mail.internet.*;
import javax.mail.*
import javax.activation.*

jenkins = jenkins.model.Jenkins.instance

def sendMail ( agent, cause ) {
  message = agent + " agent is down. Check http://JENKINS_HOSTNAME:JENKINS_PORT/computer/" + agent + "\nBecause " + cause
  subject = agent + " agent is offline"
  toAddress = "JENKINS_ADMIN@YOUR_DOMAIN"
  fromAddress = "JENKINS@YOUR_DOMAIN"
  host = "SMTP_SERVER"
  port = "SMTP_PORT"

  Properties mprops = new Properties();
  mprops.setProperty("mail.transport.protocol","smtp");
  mprops.setProperty("mail.host",host);
  mprops.setProperty("mail.smtp.port",port);

  Session lSession = Session.getDefaultInstance(mprops,null);
  MimeMessage msg = new MimeMessage(lSession);

  //tokenize out the recipients in case they came in as a list
  StringTokenizer tok = new StringTokenizer(toAddress,";");
  ArrayList emailTos = new ArrayList();
  while(tok.hasMoreElements()) {
    emailTos.add(new InternetAddress(tok.nextElement().toString()));
  }
  InternetAddress[] to = new InternetAddress[emailTos.size()];
  to = (InternetAddress[]) emailTos.toArray(to);
  msg.setRecipients(MimeMessage.RecipientType.TO,to);
  InternetAddress fromAddr = new InternetAddress(fromAddress);
  msg.setFrom(fromAddr);
  msg.setFrom(new InternetAddress(fromAddress));
  msg.setSubject(subject);
  msg.setText(message)

  Transport transporter = lSession.getTransport("smtp");
  transporter.connect();
  transporter.send(msg);
}

def getEnviron(computer) {
  def env
  def thread = Thread.start("Getting env from ${computer.name}", { env = computer.environment })
  thread.join(2000)
  if (thread.isAlive()) thread.interrupt()
  env
}

def agentAccessible(computer) {
  getEnviron(computer)?.get('PATH') != null
}

def numberOfflineNodes = 0
def numberNodes = 0
for (agent in jenkins.getNodes()) {
  def computer = agent.computer
  numberNodes ++
  println ""
  println "Checking computer ${computer.name}:"
  def isOK = (agentAccessible(computer) && !computer.offline)
  if (isOK) {
    println "\t\tOK, got PATH back from agent ${computer.name}."
    println('\tcomputer.isOffline: ' + computer.isOffline());
    println('\tcomputer.isTemporarilyOffline: ' + computer.isTemporarilyOffline());
    println('\tcomputer.getOfflineCause: ' + computer.getOfflineCause());
    println('\tcomputer.offline: ' + computer.offline);
  } else {
    numberOfflineNodes ++
    println "  ERROR: can't get PATH from agent ${computer.name}."
    println('\tcomputer.isOffline: ' + computer.isOffline());
    println('\tcomputer.isTemporarilyOffline: ' + computer.isTemporarilyOffline());
    println('\tcomputer.getOfflineCause: ' + computer.getOfflineCause());
    println('\tcomputer.offline: ' + computer.offline);
    sendMail(computer.name, computer.getOfflineCause().toString())
    if (computer.isTemporarilyOffline()) {
      if (!computer.getOfflineCause().toString().contains("Disconnected by")) {
        computer.setTemporarilyOffline(false, agent.getComputer().getOfflineCause())
      }
    } else {
        computer.connect(true)
    }
  }
 }
println ("Number of Offline Nodes: " + numberOfflineNodes)
println ("Number of Nodes: " + numberNodes)

for jenkins master

execute gc

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

before = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
System.gc();
after = Runtime.getRuntime().totalMemory() - Runtime.getRuntime().freeMemory();
println I18N.getFormattedString("ramasse_miette_execute", Math.round((before - after) / 1024));

display http sessions

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

println SessionListener.getSessionCount() + " sessions:";
sessions = SessionListener.getAllSessionsInformations();
for (session in sessions) {
    println session;
}

display a simple threads dump

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

java = new JavaInformations(Parameters.getServletContext(), true);
threads = java.getThreadInformationsList();
println threads.size() + " threads (" + java.activeThreadCount + " http threads active):";
for (thread in threads) {
  println "";
  println thread;
  for (s in thread.getStackTrace())
    println "    " + s;
}

display deadlocked threads

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

java = new JavaInformations(Parameters.getServletContext(), true);
threads = java.getThreadInformationsList();
deadlocked = new java.util.ArrayList();
for (thread in threads) {
  if (thread.deadlocked)
    deadlocked.add(thread);
}
println deadlocked.size() + " deadlocked threads / " + threads.size() + " threads (" + java.activeThreadCount + " http threads active)";
for (thread in deadlocked) {
  println "";
  println thread;
  for (s in thread.getStackTrace())
    println "    " + s;
}

display some memory data

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

memory = new MemoryInformations();
println "\nused memory:\n    " + Math.round(memory.usedMemory / 1024 / 1024) + " Mb";
println "\nmax memory:\n    " + Math.round(memory.maxMemory / 1024 / 1024) + " Mb";
println "\nused perm gen:\n    " + Math.round(memory.usedPermGen / 1024 / 1024) + " Mb";
println "\nmax perm gen:\n    " + Math.round(memory.maxPermGen / 1024 / 1024) + " Mb";
println "\nused non heap:\n    " +       Math.round(memory.usedNonHeapMemory / 1024 / 1024) + " Mb";
println "\nused physical memory:\n    " +       Math.round(memory.usedPhysicalMemorySize / 1024 / 1024) + " Mb";
println "\nused swap space:\n    " +       Math.round(memory.usedSwapSpaceSize / 1024 / 1024) + " Mb";

display some jvm data

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

java = new JavaInformations(Parameters.getServletContext(), true);
println "\nsessions count:\n    "            + java.sessionCount;
println "\nactive HTTP threads count:\n    " + java.activeThreadCount;
println "\nthreads count:\n    "             + java.threadCount;
println "\nsystem load average:\n    "       + java.systemLoadAverage;
println "\nsystem cpu load:\n    "           + java.systemCpuLoad; // since 1.59
println "\navailable processors:\n    "      + java.availableProcessors;
println "\nhost:\n    "                      + java.host;
println "\nos:\n    "                        + java.os;
println "\njava version:\n    "              + java.javaVersion;
println "\njvm version:\n    "               + java.jvmVersion;
println "\npid:\n    "                       + java.pid;
println "\nserver info:\n    "               + java.serverInfo;
println "\ncontext path:\n    "              + java.contextPath;
println "\nstart date:\n    "                + java.startDate;
println "\nfree disk space in Jenkins directory:\n    " + Math.round(java.freeDiskSpaceInTemp / 1024 / 1024) + " Mb";

display heap histogram (object instances per class)

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

classes = VirtualMachine.createHeapHistogram().getHeapHistogram();
println "class    instances    bytes    source";
println "=====================================";
for ( c in classes ) {
  println c.name + "    " + c.instancesCount + "    " + c.bytes + "    " + c.source;
}

take a heap dump

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

if (System.getProperty("java.vendor").contains("IBM")) {
  Action.HEAP_DUMP.ibmHeapDump();
  println I18N.getString("heap_dump_genere_ibm");
} else {
  heapDumpPath = Action.HEAP_DUMP.heapDump().getPath();
  println I18N.getFormattedString("heap_dump_genere", heapDumpPath);
}

display some MBean attribute value

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

exampleAttribute = "java.lang:type=OperatingSystem.ProcessCpuTime";
println exampleAttribute + " = " + MBeans.getConvertedAttributes(exampleAttribute);
Display stats of builds and build steps having mean time greater than severe threshold
(By default, severe threshold = 2 x stddev of all durations and warning threshold = 1 x stddev)

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

buildCounter = CounterRunListener.getBuildCounter();
aggreg = new CounterRequestAggregation(buildCounter);
for ( request in aggreg.getRequests() ) {
  if ( request.getMean() >= aggreg.getSevereThreshold()
       || request.getCpuTimeMean() >= aggreg.getSevereThreshold() ) {
      println( request.getName()
               + ", hits=" + request.getHits()
               + ", mean=" + request.getMean()
               + ", max=" + request.getMaximum()
               + ", stddev=" + request.getStandardDeviation()
               + ", cpuTimeMean=" + request.getCpuTimeMean()
               + ", systemErrorPercentage=" + request.getSystemErrorPercentage()
      );
   }
}

send alerts

[!TIP|label:references:]
suppose that you want to check:
every 15 minutes on the Jenkins master,
if the system load average is above 50
if the active HTTP threads count is above 100
if there are deadlocked threads
if there are less than 10 Gb free disk space left:
by:
create a freestyle job in jenkins by clicking "New Item".
check "build periodically" and write a schedule, "*/15 * * * *" for example.
add a build step "execute system groovy script" and write a script
- or any script with monitoring values in this page - add a post-build action "E-mail Notification" and write your email in "Recipients". - you can also configure "Discard old builds" and write a description. - save. - click "Build now" to test it.

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

java = new JavaInformations(Parameters.getServletContext(), true);
memory = java.memoryInformations;
println "used memory = " + Math.round(memory.usedMemory / 1024 / 1024) + " Mb";
println "active HTTP threads count = " + java.activeThreadCount;
println "system load average = " + java.systemLoadAverage;
println "free disk space in Jenkins directory = " + Math.round(java.freeDiskSpaceInTemp / 1024 / 1024) + " Mb";

threads = java.getThreadInformationsList();
deadlocked = new java.util.ArrayList();
for (thread in threads) {
  if (thread.deadlocked)
    deadlocked.add(thread);
}
println deadlocked.size() + " deadlocked threads / " + threads.size() + " threads";
for (thread in deadlocked) {
  println "";
  println thread;
  for (s in thread.getStackTrace())
    println "    " + s;
}

if (java.systemLoadAverage > 50) throw new Exception("Alert for Jenkins: systemLoadAverage is " + java.systemLoadAverage);
if (java.activeThreadCount > 100) throw new Exception("Alert for Jenkins: activeThreadCount is " + java.activeThreadCount);
if (deadlocked.size() > 0) throw new Exception("Alert for Jenkins: " + deadlocked.size() + " deadlocked threads");
if (java.freeDiskSpaceInTemp / 1024 / 1024 < 10000) throw new Exception("Alert for Jenkins: only " + Math.round(java.freeDiskSpaceInTemp / 1024 / 1024) + " Mb free disk space left");

for jenkins agents

display jvm data, memory data, deadlocked threads by node

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

String nodeName = null ; // null for all nodes, not null for a particular node
Map mapByNodeName = new RemoteCallHelper(nodeName).collectJavaInformationsListByName();
for (node in mapByNodeName.keySet()) {
  java = mapByNodeName.get(node);
  println "\nNode:\n  " + node;

  println "\nsessions count:\n    " + java.sessionCount;
  println "\nactive HTTP threads count:\n    " + java.activeThreadCount;
  println "\nthreads count:\n    " + java.threadCount;
  println "\nsystem load average:\n    " + java.systemLoadAverage;
  println "\nsystem cpu load:\n    " + java.systemCpuLoad; // since 1.59
  println "\navailable processors:\n    " + java.availableProcessors;
  println "\nhost:\n    " + java.host;
  println "\nos:\n    " + java.os;
  println "\njava version:\n    " + java.javaVersion;
  println "\njvm version:\n    " + java.jvmVersion;
  println "\npid:\n    " + java.pid;
  println "\nserver info:\n    " + java.serverInfo;
  println "\ncontext path:\n    " + java.contextPath;
  println "\nstart date:\n    " + java.startDate;
  println "";

  memory = java.memoryInformations;
  println "\nused memory:\n    " + Math.round(memory.usedMemory / 1024 / 1024) + " Mb";
  println "\nmax memory:\n    " + Math.round(memory.maxMemory / 1024 / 1024) + " Mb";
  println "\nused perm gen:\n    " + Math.round(memory.usedPermGen / 1024 / 1024) + " Mb";
  println "\nmax perm gen:\n    " + Math.round(memory.maxPermGen / 1024 / 1024) + " Mb";
  println "\nused non heap:\n    " +       Math.round(memory.usedNonHeapMemory / 1024 / 1024) + " Mb";
  println "\nused physical memory:\n    " +       Math.round(memory.usedPhysicalMemorySize / 1024 / 1024) + " Mb";
  println "\nused swap space:\n    " +       Math.round(memory.usedSwapSpaceSize / 1024 / 1024) + " Mb";
  println "";

  threads = java.getThreadInformationsList();
  deadlocked = new java.util.ArrayList();
  for (thread in threads) {
    if (thread.deadlocked)
      deadlocked.add(thread);
  }
  println deadlocked.size() + " deadlocked threads / " + threads.size() + " threads (" + java.activeThreadCount + " threads active)";
  for (thread in deadlocked) {
    println "";
    println thread;
    for (s in thread.getStackTrace())
      println "    " + s;
  }
  println "";

  println "*************************************************************";
  println "";
}

display some mbean attributes values by node

import net.bull.javamelody.*;
import net.bull.javamelody.internal.model.*;
import net.bull.javamelody.internal.common.*;

String exampleAttributes = "java.lang:type=OperatingSystem.ProcessCpuTime|java.lang:type=Memory.HeapMemoryUsage";
String nodeName = null;         // null for all nodes, not null for a particular node
List values = new RemoteCallHelper(nodeName).collectJmxValues(exampleAttributes);
for (String value in values) {
  println exampleAttributes + " = " + value;
}

Previousstage Nextsecurity & authorization

Last updated 7 months ago

Was this helpful?

get information

get all

Computer and Node

get projects tied to agent

get agent credentialsId

get agent environment variable

get agent labels

cloud agents

check how many cloud agent running

KubernetesComputer

executor

basic usage

stop all running builds via WorkflowRun

force interrupt executors

to WorkUnit and SubTask ( ExecutorStepExecution.PlaceholderTask )

to Computer

update agent label

update agent credentialsId

universal agent update

disconnect agent

temporarily offline agent

restart agent

delete agent

for jenkins master

send alerts

for jenkins agents

get information

get all

Computer and Node

get projects tied to agent

get agent credentialsId

get agent environment variable

get agent labels

cloud agents

check how many cloud agent running

KubernetesComputer

executor

basic usage

stop all running builds via WorkflowRun

force interrupt executors

to

to WorkUnit and SubTask ( ExecutorStepExecution.PlaceholderTask )

to Computer

update agent label

update agent credentialsId

universal agent update

disconnect agent

temporarily offline agent

restart agent

delete agent

for jenkins master

send alerts

for jenkins agents

to

`Computer` and `Node`

to `WorkUnit` and `SubTask` ( `ExecutorStepExecution.PlaceholderTask` )

to `Computer`

`Computer` and `Node`

to `WorkUnit` and `SubTask` ( `ExecutorStepExecution.PlaceholderTask` )

to `Computer`