fix: handle ext conns in hybrid envs

if a physical switch is connected to a hardware external, the
correponding ExternalConnection does not need to be created.
Since the connection does not specify the external, the addLink
function cannot know from the current config whether that
connection is physical or virtual. Work around this by also
annotating hardware ExternalConnections and ignoring them
when processing the virtual externals.

Signed-off-by: Emanuele Di Pascale <emanuele@githedgehog.com>

Author: edipascale

pkg/hhfab/vlabconfig.go

@@ -662,17 +662,26 @@ func createVLABConfig(ctx context.Context, controls []fabapi.ControlNode, nodes
 				}
 			}
 		} else if conn.Spec.External != nil {
+			// in hybrid environments we can have physical switches connected to
+			// both virtual and hardware externals. Since a connection is not associated
+			// with a specific external, we need to annotate the connection itself
+			if isHardware(&conn) {
+				slog.Debug("Skipping hardware external connection", "connection", conn.Name)
+
+				continue
+			}
 			if externalID > MaxExternalConns {
 				return nil, fmt.Errorf("too many external connections") //nolint:goerr113
 			}
 
 			switchName := conn.Spec.External.Link.Switch.DeviceName()
-			// add the link representing the external connection
+			// add the link representing the virtual external connection
+			// note that if the switch is hardware, we will require passthrough annotations
 			nicName := fmt.Sprintf("enp2s%d", externalID)
 			externalID++
 			toStr := fmt.Sprintf("%s/%s", ExternalVMName, nicName)
 			if err := addLink(conn.Spec.External.Link.Switch.Port, toStr); err != nil {
-				return nil, fmt.Errorf("failed to add link for external connection %q: %w", conn.Name, err)
+				return nil, fmt.Errorf("failed to add link for virtual external connection %q: %w", conn.Name, err)
 			}
 			extNicCfg := ExternalNICCfg{
 				Attachments: make([]ExternalAttachCfg, 0),