From 0a86133da59261e7ebb3e5d465e2a619598e15e2 Mon Sep 17 00:00:00 2001
From: Gabriel Mougard <gabriel.mougard@canonical.com>
Date: Thu, 7 Dec 2023 19:22:13 +0100
Subject: [PATCH] microcloud/preseed: Allow the creation of an underlay network
 in preseed mode

Signed-off-by: Gabriel Mougard <gabriel.mougard@canonical.com>
---
 cmd/microcloud/main_init_preseed.go | 75 +++++++++++++++++++++++++++--
 1 file changed, 72 insertions(+), 3 deletions(-)

diff --git a/cmd/microcloud/main_init_preseed.go b/cmd/microcloud/main_init_preseed.go
index 84a51e774..7f61e8c9c 100644
--- a/cmd/microcloud/main_init_preseed.go
+++ b/cmd/microcloud/main_init_preseed.go
@@ -38,6 +38,7 @@ type Preseed struct {
 type System struct {
 	Name            string      `yaml:"name"`
 	UplinkInterface string      `yaml:"ovn_uplink_interface"`
+	UnderlayIP      string      `yaml:"underlay_ip"`
 	Storage         InitStorage `yaml:"storage"`
 }
 
@@ -178,6 +179,7 @@ func (c *CmdControl) RunPreseed(cmd *cobra.Command, init bool) error {
 // validate validates the unmarshaled preseed input.
 func (p *Preseed) validate(name string, bootstrap bool) error {
 	uplinkCount := 0
+	underlayCount := 0
 	directCephCount := 0
 	directLocalCount := 0
 	localInit := false
@@ -203,6 +205,15 @@ func (p *Preseed) validate(name string, bootstrap bool) error {
 			uplinkCount++
 		}
 
+		if system.UnderlayIP != "" {
+			_, _, err := net.ParseCIDR(system.UnderlayIP)
+			if err != nil {
+				return fmt.Errorf("Invalid underlay IP: %w", err)
+			}
+
+			underlayCount++
+		}
+
 		if len(system.Storage.Ceph) > 0 {
 			directCephCount++
 		}
@@ -232,6 +243,11 @@ func (p *Preseed) validate(name string, bootstrap bool) error {
 		return fmt.Errorf("Some systems are missing an uplink interface")
 	}
 
+	containsUnderlay := underlayCount > 0
+	if containsUnderlay && underlayCount < len(p.Systems) {
+		return fmt.Errorf("Some systems are missing an underlay interface")
+	}
+
 	containsCephStorage = directCephCount > 0
 	if containsCephStorage && directCephCount < 3 && len(p.Storage.Ceph) == 0 && bootstrap {
 		return fmt.Errorf("At least 3 systems must specify ceph storage disks")
@@ -449,10 +465,15 @@ func (p *Preseed) Parse(s *service.Handler, bootstrap bool) (map[string]InitSyst
 
 	lxd := s.Services[types.LXD].(*service.LXDService)
 	ifaceByPeer := map[string]string{}
+	ovnUnderlayNeeded := false
 	for _, cfg := range p.Systems {
 		if cfg.UplinkInterface != "" {
 			ifaceByPeer[cfg.Name] = cfg.UplinkInterface
 		}
+
+		if cfg.UnderlayIP != "" {
+			ovnUnderlayNeeded = true
+		}
 	}
 
 	// If we have specified any part of OVN config, implicitly assume we want to set it up.
@@ -477,10 +498,58 @@ func (p *Preseed) Parse(s *service.Handler, bootstrap bool) (map[string]InitSyst
 				ifaceByPeer[peer] = nets[0].Name
 			}
 		}
-	}
 
-	if usingOVN && bootstrap && len(ifaceByPeer) < 3 {
-		return nil, fmt.Errorf("Failed to find at least 3 interfaces on 3 machines for OVN configuration")
+		if bootstrap && len(ifaceByPeer) < 3 {
+			return nil, fmt.Errorf("Failed to find at least 3 interfaces on 3 machines for OVN configuration")
+		}
+
+		// Check the preseed underlay network configuration against the available ips.
+		if ovnUnderlayNeeded {
+			underlayNetworks, err := lxd.GetUnderlayInterfaces(context.Background(), bootstrap, infos)
+			if err != nil {
+				return nil, err
+			}
+
+			if len(underlayNetworks) != len(p.Systems) {
+				return nil, fmt.Errorf("Failed to find all underlay IPs on the network")
+			}
+
+			underlays := make(map[string]string, len(p.Systems))
+			for _, sys := range p.Systems {
+				underlays[sys.Name] = sys.UnderlayIP
+			}
+
+			underlayCount := 0
+			for peer, networks := range underlayNetworks {
+				for _, net := range networks {
+					if len(net.Addresses) != 0 {
+						for _, cidrAddr := range net.Addresses {
+							if underlays[peer] == cidrAddr {
+								underlayCount = underlayCount + 1
+								goto out
+							}
+						}
+					}
+				}
+
+			out:
+			}
+
+			if underlayCount != len(p.Systems) {
+				return nil, fmt.Errorf("Failed to find all underlay IPs on the network")
+			}
+
+			// Apply the underlay IPs to the systems.
+			for peer, system := range systems {
+				ip, _, err := net.ParseCIDR(underlays[peer])
+				if err != nil {
+					return nil, fmt.Errorf("Failed to parse underlay IP: %w", err)
+				}
+
+				system.OVNGeneveAddr = ip.String()
+				systems[peer] = system
+			}
+		}
 	}
 
 	for peer, iface := range ifaceByPeer {