fix: ipv4 destination dns resolution

agent/xds/clusters.go

@@ -1494,7 +1494,7 @@ func (s *ResourceGenerator) makeTerminatingHostnameCluster(snap *proxycfg.Config
 		// Having an empty config enables outlier detection with default config.
 		OutlierDetection:     &envoy_cluster_v3.OutlierDetection{},
 		ClusterDiscoveryType: &envoy_cluster_v3.Cluster_Type{Type: envoy_cluster_v3.Cluster_LOGICAL_DNS},
-		DnsLookupFamily:      envoy_cluster_v3.Cluster_AUTO,
+		DnsLookupFamily:      envoy_cluster_v3.Cluster_V4_ONLY,
 	}
 
 	rate := 10 * time.Second

agent/xds/testdata/clusters/transparent-proxy-terminating-gateway-destinations-only.latest.golden

@@ -138,6 +138,7 @@
         ]
       },
       "dnsRefreshRate": "10s",
+      "dnsLookupFamily": "V4_ONLY",
       "outlierDetection": {
 
       }
@@ -167,6 +168,7 @@
         ]
       },
       "dnsRefreshRate": "10s",
+      "dnsLookupFamily": "V4_ONLY",
       "outlierDetection": {
 
       },
@@ -218,6 +220,7 @@
         ]
       },
       "dnsRefreshRate": "10s",
+      "dnsLookupFamily": "V4_ONLY",
       "outlierDetection": {
 
       }
@@ -247,6 +250,7 @@
         ]
       },
       "dnsRefreshRate": "10s",
+      "dnsLookupFamily": "V4_ONLY",
       "outlierDetection": {
 
       }