Ben Parees of Red Hat reports: When an s2i build is run, if the builder image contains ONBUILD commands, or if the builder image does not contain a "tar" binary, s2i will construct a Dockerfile and docker build it in order to execute the ONBUILD commands or to layer the source code into the image for assembly. This is a problem for openshift because the docker build container is not running with network isolation.
Acknowledgments: Name: Ben Parees (Red Hat)
This is an issue only when multi-tenant SDN is enabled and the build is run in a namespace that would normally be isolated from pods in other namespaces. The pod can access normal network functions as if the multitenant SDN was not enabled (equivalent to when the standard SDN function is enabled).
This issue has been addressed in the following products: Red Hat OpenShift Enterprise 3.2 Via RHSA-2016:1094 https://access.redhat.com/errata/RHSA-2016:1094