Merge pull request #45915 from akerouanton/create-overlay-on-non-manager

libnet: Return proper error when overlay network can't be created

api/swagger.yaml

@@ -9900,7 +9900,9 @@ paths:
               Id: "22be93d5babb089c5aab8dbc369042fad48ff791584ca2da2100db837a1c7c30"
               Warning: ""
         403:
-          description: "operation not supported for pre-defined networks"
+          description: |
+            Forbidden operation. This happens when trying to create a network named after a pre-defined network,
+            or when trying to create an overlay network on a daemon which is not part of a Swarm cluster.
           schema:
             $ref: "#/definitions/ErrorResponse"
         404:

daemon/network.go

@@ -293,6 +293,16 @@ func (daemon *Daemon) createNetwork(cfg *config.Config, create types.NetworkCrea
 		return nil, PredefinedNetworkError(create.Name)
 	}
 
+	c := daemon.netController
+	driver := create.Driver
+	if driver == "" {
+		driver = c.Config().DefaultDriver
+	}
+
+	if driver == "overlay" && !daemon.cluster.IsManager() && !agent {
+		return nil, errdefs.Forbidden(errors.New(`This node is not a swarm manager. Use "docker swarm init" or "docker swarm join" to connect this node to swarm and try again.`))
+	}
+
 	var warning string
 	nw, err := daemon.GetNetworkByName(create.Name)
 	if err != nil {
@@ -311,12 +321,6 @@ func (daemon *Daemon) createNetwork(cfg *config.Config, create types.NetworkCrea
 		warning = fmt.Sprintf("Network with name %s (id : %s) already exists", nw.Name(), nw.ID())
 	}
 
-	c := daemon.netController
-	driver := create.Driver
-	if driver == "" {
-		driver = c.Config().DefaultDriver
-	}
-
 	networkOptions := make(map[string]string)
 	for k, v := range create.Options {
 		networkOptions[k] = v
@@ -375,10 +379,6 @@ func (daemon *Daemon) createNetwork(cfg *config.Config, create types.NetworkCrea
 
 	n, err := c.NewNetwork(driver, create.Name, id, nwOptions...)
 	if err != nil {
-		if errors.Is(err, libnetwork.ErrDataStoreNotInitialized) {
-			//nolint: revive
-			return nil, errors.New(`This node is not a swarm manager. Use "docker swarm init" or "docker swarm join" to connect this node to swarm and try again.`)
-		}
 		return nil, err
 	}