Jobs failing when "Expose DOCKER_HOST" is checked

Hello,

As the title says, jobs are failing when the “Expose DOCKER_HOST” is checked in the global settings, the job console shows the following stack trace:

FATAL: null
java.lang.NullPointerException
	at com.nirima.jenkins.plugins.docker.DockerBuildVariableContributor.buildVariablesFor(DockerBuildVariableContributor.java:34)
	at hudson.model.AbstractBuild.getBuildVariables(AbstractBuild.java:1000)
	at org.jenkinsci.plugins.envinject.util.RunHelper.getBuildVariables(RunHelper.java:80)
	at org.jenkinsci.plugins.envinject.util.RunHelper.getBuildVariables(RunHelper.java:154)
	at org.jenkinsci.plugins.envinject.EnvInjectListener.setUpEnvironmentWithoutJobPropertyObject(EnvInjectListener.java:235)
	at org.jenkinsci.plugins.envinject.EnvInjectListener.setUpEnvironment(EnvInjectListener.java:51)
	at hudson.model.AbstractBuild$AbstractBuildExecution.createLauncher(AbstractBuild.java:534)
	at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:454)
	at hudson.model.Run.execute(Run.java:1737)
	at hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43)
	at hudson.model.ResourceController.execute(ResourceController.java:97)
	at hudson.model.Executor.run(Executor.java:419)
Finished: FAILURE

“Computer log”:

[10/11/17 01:14:34] [SSH] Opening SSH connection to 10.96.14.31:36850.
Connection refused (Connection refused)
SSH Connection failed with IOException: "Connection refused (Connection refused)".
java.io.IOException: There was a problem while connecting to 10.96.14.31:36850
	at com.trilead.ssh2.Connection.connect(Connection.java:834)
	at com.trilead.ssh2.Connection.connect(Connection.java:703)
	at com.trilead.ssh2.Connection.connect(Connection.java:617)
	at hudson.plugins.sshslaves.SSHLauncher.openConnection(SSHLauncher.java:1284)
	at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:804)
	at hudson.plugins.sshslaves.SSHLauncher$2.call(SSHLauncher.java:793)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.ConnectException: Connection refused (Connection refused)
	at java.net.PlainSocketImpl.socketConnect(Native Method)
	at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
	at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
	at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
	at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
	at java.net.Socket.connect(Socket.java:589)
	at com.trilead.ssh2.transport.TransportManager.establishConnection(TransportManager.java:367)
	at com.trilead.ssh2.transport.TransportManager.initialize(TransportManager.java:480)
	at com.trilead.ssh2.Connection.connect(Connection.java:774)
	... 9 more
[10/11/17 01:14:34] Launch failed - cleaning up connection
[10/11/17 01:14:34] [SSH] Connection closed.

And here’s the failed build.xml:

<?xml version='1.0' encoding='UTF-8'?>
<build>
  <actions>
    <hudson.model.CauseAction>
      <causeBag class="linked-hash-map">
        <entry>
          <hudson.model.Cause_-UserIdCause>
            <userId>ffarah</userId>
          </hudson.model.Cause_-UserIdCause>
          <int>1</int>
        </entry>
      </causeBag>
    </hudson.model.CauseAction>
    <jenkins.metrics.impl.TimeInQueueAction plugin="metrics@3.1.2.10">
      <queuingDurationMillis>3378</queuingDurationMillis>
    </jenkins.metrics.impl.TimeInQueueAction>
    <io.jenkins.blueocean.service.embedded.BlueOceanUrlAction plugin="blueocean-rest-impl@1.2.4">
      <blueOceanUrlObject class="io.jenkins.blueocean.service.embedded.BlueOceanUrlObjectImpl">
        <mappedUrl>blue/organizations/jenkins/Dev.eng-pst.devtools.test-jenkins/detail/Dev.eng-pst.devtools.test-jenkins/8</mappedUrl>
      </blueOceanUrlObject>
    </io.jenkins.blueocean.service.embedded.BlueOceanUrlAction>
    <org.jenkinsci.plugins.envinject.EnvInjectPluginAction plugin="envinject@2.1.4"/>
    <com.nirima.jenkins.plugins.docker.action.DockerBuildAction plugin="docker-plugin@0.17">
      <containerId>bd454f6d01f27b3c10e68bec511d07738875e8530cbcfc372b853f3ef30d1d4d</containerId>
      <remoteFsMapping>/var/lib/jenkins/workspace</remoteFsMapping>
    </com.nirima.jenkins.plugins.docker.action.DockerBuildAction>
  </actions>
  <queueId>56</queueId>
  <timestamp>1507684471855</timestamp>
  <startTime>1507684471862</startTime>
  <result>FAILURE</result>
  <duration>101</duration>
  <charset>US-ASCII</charset>
  <keepLog>false</keepLog>
  <builtOn>Docker-10a216054f4921</builtOn>
  <hudsonVersion>2.73.1</hudsonVersion>
  <scm class="hudson.scm.NullChangeLogParser"/>
  <culprits class="com.google.common.collect.EmptyImmutableSortedSet"/>
</build>

Any idea why this is happening? When I uncheck the option the build succeeds.

Fadi

[ndeloof]

https://github.com/jenkinsci/docker-plugin/commit/9cd0f050b4f7c9add89cc0bda9ec874c323af514 is not in a released version yet

[farahfa]

Oh my bad, I thought the fix was in 0.18.