cluster: introduce NodeID and ZoneID types

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

pkg/cluster/cluster_import.go

@@ -45,7 +45,7 @@ func (m *Cluster) initZones(opts *ScanOptions) error {
 
 func (m *Cluster) initZone(z *Zone, _ *ScanOptions) error {
 	var hasMissing bool
-	var lastMachineID int
+	var lastMachineID NodeID
 
 	z.zones = m
 	z.logger = m
@@ -58,7 +58,7 @@ func (m *Cluster) initZone(z *Zone, _ *ScanOptions) error {
 		case p.ID == 0:
 			hasMissing = true
 		case p.ID > lastMachineID:
-			lastMachineID = z.ID
+			lastMachineID = p.ID
 		}
 
 		return false