If --method is not given the workflow commands insert method=nfs into ks_meta by default. But sometimes a tree will only be available over other protocols (commonly HTTP). If the user doesn't request a specific method using the --method option then the workflow commands should leave method= unset in ks_meta (and thus letting Beaker pick any suitable protocol).
I just realised we have this old open patch about this: http://gerrit.beaker-project.org/2229
This bug fix is included in beaker-client-22.0-0.git.59.cbcb4e8 which is available for download here: https://beaker-project.org/nightlies/develop/
Steps to reproduce: 1. Use bkr workflow-simple to create a job, without using --method option, for example: bkr workflow-simple --family RedHatEnterpriseLinux6 --arch x86_64 --task /distribution/reservesys Actual results: Job XML contains ks_meta="method=nfs". Recipe will therefore abort if the distro is only available over HTTP. Expected results: Job XML should not contain any method= argument in ks_meta.
Beaker 22.0 has been released.