Neutron: Enable sharing of network namespaces with host

This PS enables sharing of network namespaces with the host,
allowing for hitless upgrades of agents, and much simpler debugging.

It does however require mount propogation to be enabled in kubernetes
which is a alpha gated feature introduced in 1.8, and enabled by default
as a beta feature in 1.10.

Depends-On: I7a37f45ff6061b144c6f04233712cd84fccb3e83
Change-Id: I2a191a343fe637cbfd9e4af5277f9784af736dd1

neutron/templates/daemonset-dhcp-agent.yaml

@@ -113,6 +113,11 @@ spec:
             {{- end }}
             - name: socket
               mountPath: /var/lib/neutron/openstack-helm
+            {{- if .Values.network.share_namespaces }}
+            - name: host-run-netns
+              mountPath: /run/netns
+              mountPropagation: Bidirectional
+            {{- end }}
 {{ if $mounts_neutron_dhcp_agent.volumeMounts }}{{ toYaml $mounts_neutron_dhcp_agent.volumeMounts | indent 12 }}{{ end }}
       volumes:
         - name: neutron-bin
@@ -131,6 +136,11 @@ spec:
         - name: socket
           hostPath:
             path: /var/lib/neutron/openstack-helm
+        {{- if .Values.network.share_namespaces }}
+        - name: host-run-netns
+          hostPath:
+            path: /run/netns
+        {{- end }}
 {{ if $mounts_neutron_dhcp_agent.volumes }}{{ toYaml $mounts_neutron_dhcp_agent.volumes | indent 8 }}{{ end }}
 {{- end }}
 {{- end }}

neutron/templates/daemonset-l3-agent.yaml

@@ -112,6 +112,11 @@ spec:
               readOnly: true
             - name: socket
               mountPath: /var/lib/neutron/openstack-helm
+            {{- if .Values.network.share_namespaces }}
+            - name: host-run-netns
+              mountPath: /run/netns
+              mountPropagation: Bidirectional
+            {{- end }}
 {{ if $mounts_neutron_l3_agent.volumeMounts }}{{ toYaml $mounts_neutron_l3_agent.volumeMounts | indent 12 }}{{ end }}
       volumes:
         - name: neutron-bin
@@ -133,6 +138,11 @@ spec:
         - name: socket
           hostPath:
             path: /var/lib/neutron/openstack-helm
+        {{- if .Values.network.share_namespaces }}
+        - name: host-run-netns
+          hostPath:
+            path: /run/netns
+        {{- end }}
 {{ if $mounts_neutron_l3_agent.volumes }}{{ toYaml $mounts_neutron_l3_agent.volumes | indent 8 }}{{ end }}
 {{- end }}
 {{- end }}

neutron/templates/daemonset-metadata-agent.yaml

@@ -127,6 +127,11 @@ spec:
             {{- end }}
             - name: socket
               mountPath: /var/lib/neutron/openstack-helm
+            {{- if .Values.network.share_namespaces }}
+            - name: host-run-netns
+              mountPath: /run/netns
+              mountPropagation: Bidirectional
+            {{- end }}
 {{ if $mounts_neutron_metadata_agent.volumeMounts }}{{ toYaml $mounts_neutron_metadata_agent.volumeMounts | indent 12 }}{{ end }}
       volumes:
         - name: neutron-bin
@@ -145,6 +150,11 @@ spec:
         - name: socket
           hostPath:
             path: /var/lib/neutron/openstack-helm
+        {{- if .Values.network.share_namespaces }}
+        - name: host-run-netns
+          hostPath:
+            path: /run/netns
+        {{- end }}
 {{ if $mounts_neutron_metadata_agent.volumes }}{{ toYaml $mounts_neutron_metadata_agent.volumes | indent 8 }}{{ end }}
 {{- end }}
 {{- end }}

neutron/values.yaml

@@ -80,6 +80,10 @@ network:
   # possible options: openvswitch, linuxbridge, sriov
   backend:
     - openvswitch
+  # NOTE(Portdirect): Share network namespaces with the host,
+  # allowing agents to be restarted without packet loss and simpler
+  # debugging. This feature requires mount propagation support.
+  share_namespaces: true
   external_bridge: br-ex
   ip_address: 0.0.0.0
   interface: