This is similar to JENKINS-5661 which was set to Resolve as it could not be re-produced. I have created a slave which is activated on the same machine as the master instance of Jenkins, and I also have slaves which reside on other machines. When running a job on the slave which is on the same machine as the master instance of Jenkins, I get the error below, however this error does not occur when running the same job with the same configuration on a slave node which does not run on the same machine as the Jenkins master instance. Also, this was working for me before, however I recently upgraded Jenkins and all plugins.
Caught exception communicating with perforce. Connect to server failed; check $P4PORTcom.tek42.perforce.PerforceException: Connect to server failed; check $P4PORT
at com.tek42.perforce.parse.AbstractPerforceTemplate.getPerforceResponse(AbstractPerforceTemplate.java:406)
at com.tek42.perforce.parse.AbstractPerforceTemplate.getPerforceResponse(AbstractPerforceTemplate.java:301)
at com.tek42.perforce.parse.Workspaces.getWorkspace(Workspaces.java:61)
at hudson.plugins.perforce.PerforceSCM.getPerforceWorkspace(PerforceSCM.java:1615)
at hudson.plugins.perforce.PerforceSCM.getPerforceWorkspace(PerforceSCM.java:1576)
at hudson.plugins.perforce.PerforceSCM.checkout(PerforceSCM.java:892)
at hudson.model.AbstractProject.checkout(AbstractProject.java:1414)
at hudson.model.AbstractBuild$AbstractBuildExecution.defaultCheckout(AbstractBuild.java:671)
at jenkins.scm.SCMCheckoutStrategy.checkout(SCMCheckoutStrategy.java:88)
at hudson.model.AbstractBuild$AbstractBuildExecution.run(AbstractBuild.java:580)
at hudson.model.Run.execute(Run.java:1684)
at hudson.maven.MavenModuleSetBuild.run(MavenModuleSetBuild.java:529)
at hudson.model.ResourceController.execute(ResourceController.java:88)
at hudson.model.Executor.run(Executor.java:231)
ERROR: Unable to communicate with perforce. Connect to server failed; check $P4PORT