dns: sort zones when writing data

Signed-off-by: Alejandro Mery <amery@jpi.io>

pkg/dns/record.go

@@ -175,6 +175,16 @@ func (mgr *Manager) genRegionsSorted() []string {
 	return SortRegions(regions)
 }
 
+func (mgr *Manager) genZonesSorted() []string {
+	zones := make([]string, 0, len(mgr.zones))
+	for name := range mgr.zones {
+		zones = append(zones, name)
+	}
+
+	sort.Strings(zones)
+	return zones
+}
+
 func (mgr *Manager) genAllAddrRecords() []AddrRecord {
 	var out []AddrRecord
 

pkg/dns/write.go

@@ -14,12 +14,13 @@ func (mgr *Manager) WriteTo(w io.Writer) (int64, error) {
 	cache := make(map[string][]netip.Addr)
 
 	// zones
-	for _, z := range mgr.zones {
+	for _, zoneName := range mgr.genZonesSorted() {
+		z := mgr.zones[zoneName]
+
 		mgr.writeZoneHosts(&buf, z)
 
 		// zone alias
 		addrs := mgr.genZoneAddresses(z)
-		zoneName := z.Name
 
 		rr := AddrRecord{
 			Name: mgr.fqdn(zoneName + mgr.suffix),