cmd/microcloud: Store the interface names in preseed mode

Signed-off-by: Gabriel Mougard <gabriel.mougard@canonical.com>

cmd/microcloud/preseed.go

@@ -794,6 +794,7 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig, installedServices map
 					return nil, fmt.Errorf("Failed to parse supplied underlay IP %q", sys.UnderlayIP)
 				}
 
+				ovnUnderlayIfaceByPeer := make(map[string]string)
 				for _, iface := range addressedInterfaces[sys.Name] {
 					for _, cidr := range iface.Addresses {
 						_, subnet, err := net.ParseCIDR(cidr)
@@ -803,6 +804,7 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig, installedServices map
 
 						if subnet.Contains(underlayIP) {
 							assignedSystems[sys.Name] = true
+							ovnUnderlayIfaceByPeer[sys.Name] = iface.Network.Name
 							break
 						}
 					}
@@ -812,8 +814,14 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig, installedServices map
 					return nil, fmt.Errorf("No available interface found for OVN underlay IP %q", sys.UnderlayIP)
 				}
 
+				ifaceName, ok := ovnUnderlayIfaceByPeer[sys.Name]
+				if !ok {
+					return nil, fmt.Errorf("Failed to find OVN underlay interface name for system %q", sys.Name)
+				}
+
 				system := c.systems[sys.Name]
 				system.OVNGeneveAddr = sys.UnderlayIP
+				system.OVNGeneveIface = ifaceName
 				c.systems[sys.Name] = system
 			}
 		}
@@ -1084,8 +1092,14 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig, installedServices map
 				return nil, err
 			}
 
+			iface, err := lxd.FindInterfaceForSubnet(internalCephNetwork)
+			if err != nil {
+				return nil, err
+			}
+
 			bootstrapSystem := c.systems[s.Name]
 			bootstrapSystem.MicroCephInternalNetworkSubnet = internalCephNetwork
+			bootstrapSystem.MicroCephInternalNetworkIface = iface.Name
 			c.systems[s.Name] = bootstrapSystem
 		}
 
@@ -1102,8 +1116,14 @@ func (p *Preseed) Parse(s *service.Handler, c *initConfig, installedServices map
 				return nil, err
 			}
 
+			iface, err := lxd.FindInterfaceForSubnet(publicCephNetwork)
+			if err != nil {
+				return nil, err
+			}
+
 			bootstrapSystem := c.systems[s.Name]
 			bootstrapSystem.MicroCephPublicNetworkSubnet = publicCephNetwork
+			bootstrapSystem.MicroCephPublicNetworkIface = iface.Name
 			c.systems[s.Name] = bootstrapSystem
 		}
 	} else {