fix: only set gateway if set in context (opennebula)

Fix the network config setup.

Signed-off-by: Christian WALDBILLIG <christian@waldbillig.io>
Signed-off-by: Andrey Smirnov <andrey.smirnov@siderolabs.com>

internal/app/machined/pkg/runtime/v1alpha1/platform/opennebula/opennebula.go

@@ -127,26 +127,28 @@ func (o *OpenNebula) ParseMetadata(st state.State, oneContextPlain []byte) (*run
 						},
 					)
 
-					// Parse gateway address and create RouteSpecSpec entry
-					gateway, err := netip.ParseAddr(oneContext[ifaceName+"_GATEWAY"])
-					if err != nil {
-						return nil, fmt.Errorf("failed to parse gateway ip: %w", err)
-					}
+					if oneContext[ifaceName+"_GATEWAY"] != "" {
+						// Parse gateway address and create RouteSpecSpec entry
+						gateway, err := netip.ParseAddr(oneContext[ifaceName+"_GATEWAY"])
+						if err != nil {
+							return nil, fmt.Errorf("failed to parse gateway ip: %w", err)
+						}
 
-					route := network.RouteSpecSpec{
-						ConfigLayer: network.ConfigPlatform,
-						Gateway:     gateway,
-						OutLinkName: ifaceNameLower,
-						Table:       nethelpers.TableMain,
-						Protocol:    nethelpers.ProtocolStatic,
-						Type:        nethelpers.TypeUnicast,
-						Family:      nethelpers.FamilyInet4,
-						Priority:    network.DefaultRouteMetric,
-					}
+						route := network.RouteSpecSpec{
+							ConfigLayer: network.ConfigPlatform,
+							Gateway:     gateway,
+							OutLinkName: ifaceNameLower,
+							Table:       nethelpers.TableMain,
+							Protocol:    nethelpers.ProtocolStatic,
+							Type:        nethelpers.TypeUnicast,
+							Family:      nethelpers.FamilyInet4,
+							Priority:    network.DefaultRouteMetric,
+						}
 
-					route.Normalize()
+						route.Normalize()
 
-					networkConfig.Routes = append(networkConfig.Routes, route)
+						networkConfig.Routes = append(networkConfig.Routes, route)
+					}
 
 					// Parse DNS servers
 					dnsServers := strings.Fields(oneContext[ifaceName+"_DNS"])