Hi,
discovering the workflow plugin, i started playing with it folowing the tutorial with something like

node("master") {
echo "hello world"
}

and couldn't make it work.

I got the following exception :

Running: Allocate node : Start
Running: Allocate node : End
Running: End of Workflow
java.lang.IllegalStateException: no known slave for /opt/hosting/run/jenkins/etc/workspace/FRONT/PREPROD/testworkflow1 among []
at org.jenkinsci.plugins.workflow.support.actions.WorkspaceActionImpl.<init>(WorkspaceActionImpl.java:57)
at org.jenkinsci.plugins.workflow.support.steps.ExecutorStepExecution$PlaceholderTask$PlaceholderExecutable.run(ExecutorStepExecution.java:403)
at hudson.model.ResourceController.execute(ResourceController.java:89)
at hudson.model.Executor.run(Executor.java:240)
Finished: FAILURE

I succeeded in making ot work by adding a stage at the beginning :

stage "whatever"
node("master") {
echo "hello world"
}

I can't say if the bug is in the plugin or the tutorial. I find easy and a good practice to wrap commands in stages...

Rgds/Romain