Issue

• Currently we are using the Openshift SDN and more exactly the plugin ovs-subnet.
  Because of the fact that now we want isolation between projects I try to migrate from ovs-subnet plugin to ovs-multitenant plugin by following your
  documentation: https://docs.openshift.com/enterprise/3.1/install_config/configuring_sdn.html part "Migrating Between SDN Plug-ins".
  In summary:
  1) I modified on our 3 masters the file /etc/origin/master/master-config.yaml to put networkPluginName: "redhat/openshift-ovs-subnet"
  2) I modified on all our nodes the file /etc/origin/node/node-config.yaml to put networkPluginName: "redhat/openshift-ovs-subnet"
  3) I restarted on each master the service atomic-openshift-master-api without problem
  4) I restarted on each node the server atomic-openshift-node and I got error and more exactly:

Jun 23 14:11:23 hostname.example.com atomic-openshift-node[2668]: F0623 14:11:23.046318    2668 node.go:175] SDN Node failed: Failed to start plugin: Error fetching Net ID for namespace: default
Jun 23 14:11:23 hostname.example.com systemd[1]: atomic-openshift-node.service: main process exited, code=exited, status=255/n/a
Jun 23 14:11:23 hostname.example.com systemd[1]: Failed to start Atomic OpenShift Node.
Jun 23 14:11:23 hostname.example.com systemd[1]: Unit atomic-openshift-node.service entered failed state.

Note that if I set back the ovs-subnet it works again. So the problem is really when I switch to the new one.