https://github.com/openshift/ose/pull/1498
QE did the following scenarios on version v3.9.72, this issue had been fixed. 1. Create a namespace. Create some pods and NetworkPolicies in that namespace. Confirm with "ovs-ofctl -O OpenFlow13 dump-flows br0 table=80" on a node that there are flows referencing that namespace (via "reg0" in the OVS flow referring to the NetID of the NetNamespace associated with the Namespace). Now delete the namespace and wait for it to disappear from "oc get namespaces". All of the OVS flows referencing that namespace should now be gone. 2. Create a namespace. Create some pods and NetworkPolicies in that namespace. Kill the SDN pods and wait for them to restart. Delete the namespace. Confirm that the OVS flows are deleted just like in the above case. 2. Create a namespace. Create two pods and a "default deny" NetworkPolicy in that namespace and confirm that the pods can't talk to each other. Kill the SDN pods and wait for them to restart. Add a NetworkPolicy to the namespace to allow communication between the two pods. (Don't create any new pods or re-label the existing pods after restarting the SDN; *Only* add a NetworkPolicy.) Confirm that new OVS flows have been created and the pods can talk.
Doh. Ignore previous comment. That was meant for bug 1679270
This is being reverted from 3.11 and earlier. Note that while stale OVS flows may build up at times, there is already a periodic job that eventually cleans them up.