How to get the Jenkins master IP/hostname inside a pipeline stage executing on a slave?

Question

I have a Jenkins declarative pipeline in which I build in one stage and test in another, on different machines. I also have a Selenium hub running on the same machine as the Jenkins master.

pipeline {
  agent none
  stages {
    stage('Build') {
      agent { node { label 'builder' } }
      steps {
        sh 'build-the-app'
        stash(name: 'app', includes: 'outputs')
      }
    }
    stage('Test’) {
      agent { node { label 'tester' } }
      steps {
        unstash 'app'
        sh 'test-the-app'
      }
    }
  }
}

I'd like for the Selenium tests that run on at the Test stage to connect back to the Selenium hub on the Jenkins master machine, and that means that I need to get the IP address or hostname of the Jenkins master machine from the slave.

Is there a way to do this? The Jenkins master URL / hostname isn't in the environment variables and I'm uncertain how else to get the Jenkins master's IP address.

score 5 · Accepted Answer · answered Aug 08 '17 at 23:18

Not sure if there are better ways to do this, I am able to run

def masterIP = InetAddress.localHost.hostAddress
println "Master located at ${masterIP}"

in my Jenkinsfile. The first time I ran this code in my Jenkinsfile, the build failed with

org.jenkinsci.plugins.scriptsecurity.sandbox.RejectedAccessException: 
Scripts not permitted to use method java.net.InetAddress getHostAddress
at org.jenkinsci.plugins.scriptsecurity.sandbox.whitelists.StaticWhitelist.rejectMethod(StaticWhitelist.java:178)
at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor$6.reject(SandboxInterceptor.java:243)
at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onGetProperty(SandboxInterceptor.java:363)
at org.kohsuke.groovy.sandbox.impl.Checker$4.call(Checker.java:241)
at org.kohsuke.groovy.sandbox.impl.Checker.checkedGetProperty(Checker.java:238)
at com.cloudbees.groovy.cps.sandbox.SandboxInvoker.getProperty(SandboxInvoker.java:28)

I had to approve the method signature in Jenkins by navigating to Manage Jenkins > In-process Script Approval.

score 4 · Answer 2 · answered Dec 01 '17 at 15:26

4

Inspired from @kayvee for using BUILD_URL, the following worked from me:

def getJenkinsMaster() {
    return env.BUILD_URL.split('/')[2].split(':')[0]
}

This returns the master's hostname or IP as it would appear in the build URL. If you also require the port number remove the second split().

answered Dec 01 '17 at 15:26

urban

5,392
3
19
45

1

This won't work if Jenkins runs behind a reverse proxy. – Alex O Nov 16 '18 at 15:16

score 4 · Answer 3 · answered May 23 '18 at 16:37

4

To get current slave host :

Jenkins.getInstance().getComputer(env['NODE_NAME']).getHostName()

To get master host :

Jenkins.getInstance().getComputer('').getHostName()

answered May 23 '18 at 16:37

ldenisey

136
5

this will probably return the container id if you're running jenkins in docker – James Robert Albert Aug 19 '20 at 18:40
I confirm, this does return the docker hostname – Ordiel Sep 16 '20 at 16:46
Why master computer is called '' (empty string)??? – Barel elbaz Dec 29 '21 at 14:17

score 1 · Answer 4 · answered May 07 '20 at 15:25

You can simply do it like this way:

 stage("SomeStageName") {
     agent { label 'exampleRunOnlyOnLinuxNode' }
     steps {
         script {
              println "\n\n-- Running on machine: " + "hostname".execute().text
         }
     }
 }

and "hostname -i".execute().text will print the IP

score 0 · Answer 5 · edited Oct 13 '17 at 02:28

0

Try this below shell command

def host= sh(returnStdout: true, script: 'echo ${BUILD_URL/https:\\/\\/} | cut -d "/" -f1').trim()
println("Hostname : ${host}")

edited Oct 13 '17 at 02:28

answered Oct 13 '17 at 01:58

kayvee

1

How to get the Jenkins master IP/hostname inside a pipeline stage executing on a slave?

5 Answers5

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