Support configuration networks

- They are configuration-only networks which
  can be used to supply the configuration
  when creating regular networks.
- They do not get allocated and do net get plumbed.
  Drivers do not get to know about them.
- They can be removed, once no other network is
  using them.
- When user creates a network specifying a
  configuration network for the config, no
  other network specific configuration field
  is are accepted. User can only specify
  network operator fields (attachable, internal,...)

Signed-off-by: Alessandro Boch <aboch@docker.com>
Upstream-commit: 9ee7b4dda926a1444dc0ea50c4ca6d90c8684060
Component: engine

components/engine/daemon/network.go

@@ -320,6 +320,10 @@ func (daemon *Daemon) createNetwork(create types.NetworkCreateRequest, id string
 		libnetwork.NetworkOptionIngress(create.Ingress),
 	}
 
+	if create.ConfigOnly {
+		nwOptions = append(nwOptions, libnetwork.NetworkOptionConfigOnly())
+	}
+
 	if create.IPAM != nil {
 		ipam := create.IPAM
 		v4Conf, v6Conf, err := getIpamConfig(ipam.Config)
@@ -337,6 +341,10 @@ func (daemon *Daemon) createNetwork(create types.NetworkCreateRequest, id string
 		nwOptions = append(nwOptions, libnetwork.NetworkOptionPersist(false))
 	}
 
+	if create.ConfigFrom != nil {
+		nwOptions = append(nwOptions, libnetwork.NetworkOptionConfigFrom(create.ConfigFrom.Network))
+	}
+
 	n, err := c.NewNetwork(driver, create.Name, id, nwOptions...)
 	if err != nil {
 		if _, ok := err.(libnetwork.ErrDataStoreNotInitialized); ok {
@@ -501,10 +509,16 @@ func (daemon *Daemon) deleteNetwork(networkID string, dynamic bool) error {
 	if err := nw.Delete(); err != nil {
 		return err
 	}
-	daemon.pluginRefCount(nw.Type(), driverapi.NetworkPluginEndpointType, plugingetter.Release)
-	ipamType, _, _, _ := nw.Info().IpamConfig()
-	daemon.pluginRefCount(ipamType, ipamapi.PluginEndpointType, plugingetter.Release)
-	daemon.LogNetworkEvent(nw, "destroy")
+
+	// If this is not a configuration only network, we need to
+	// update the corresponding remote drivers' reference counts
+	if !nw.Info().ConfigOnly() {
+		daemon.pluginRefCount(nw.Type(), driverapi.NetworkPluginEndpointType, plugingetter.Release)
+		ipamType, _, _, _ := nw.Info().IpamConfig()
+		daemon.pluginRefCount(ipamType, ipamapi.PluginEndpointType, plugingetter.Release)
+		daemon.LogNetworkEvent(nw, "destroy")
+	}
+
 	return nil
 }
 

components/engine/daemon/prune.go

@@ -315,6 +315,9 @@ func (daemon *Daemon) localNetworksPrune(ctx context.Context, pruneFilters filte
 			return true
 		default:
 		}
+		if nw.Info().ConfigOnly() {
+			return false
+		}
 		if !until.IsZero() && nw.Info().Created().After(until) {
 			return false
 		}