Brad as requested please open an openshift-docs PR making sure to discuss the GCE requirements/workaround here. You may, after openning the PR, reassign this to Vikram Goyal.
Updated docs here: https://github.com/openshift/openshift-docs/pull/2783
Commit pushed to master at https://github.com/openshift/openshift-docs https://github.com/openshift/openshift-docs/commit/396c197a577afec3d3a92f1d1c8fed8d0acb32e0 Merge pull request #2853 from bfallonf/multizone-bz1372702 Bug 1372702 followup edits to #2783
Docs followup here: https://github.com/openshift/openshift-docs/pull/2853 Moving to release_pending
Link to released docs: https://docs.openshift.com/container-platform/3.3/install_config/persistent_storage/dynamically_provisioning_pvs.html#enabling-provisioner-plugins