Simplify logic in UpdateDNSNameMappings

Previously, we were always updating the ipToDNSName in place, but a
recent change was made to use a local copy instead. With that in place,
we no longer need to first remove old and then add new IPs to te map.
Instead we can just construct the new one only with the new IPs and
reassign it.

Signed-off-by: Kevin Klues <kklues@nvidia.com>

Author: klueska

cmd/compute-domain-daemon/dnsnames.go

@@ -62,8 +62,8 @@ func (m *DNSNameManager) UpdateDNSNameMappings(nodes []*nvapi.ComputeDomainNode)
 	m.Lock()
 	defer m.Unlock()
 
-	// Make a local copy of the current ipToDNSName mappings
-	ipToDNSName := maps.Clone(m.ipToDNSName)
+	// Make a local ipToDNSName mappings
+	ipToDNSName := make(IPToDNSNameMap)
 
 	// Prefilter nodes to only consider those with the matching cliqueID
 	var cliqueNodes []*nvapi.ComputeDomainNode
@@ -73,24 +73,8 @@ func (m *DNSNameManager) UpdateDNSNameMappings(nodes []*nvapi.ComputeDomainNode)
 		}
 	}
 
-	// Find and remove stale IPs from map
-	currentIPs := make(map[string]bool)
+	// Add IPs to map
 	for _, node := range cliqueNodes {
-		currentIPs[node.IPAddress] = true
-	}
-	for ip := range ipToDNSName {
-		if !currentIPs[ip] {
-			delete(ipToDNSName, ip)
-		}
-	}
-
-	// Add new IPs to map
-	for _, node := range cliqueNodes {
-		// If IP already has a DNS name, skip it
-		if _, exists := ipToDNSName[node.IPAddress]; exists {
-			continue
-		}
-
 		// Construct the DNS name from the node index
 		dnsName, err := m.constructDNSName(node)
 		if err != nil {