Add resilience to known nodes with the noaddr flag.

StackExchange.Redis/StackExchange/Redis/ClusterConfiguration.cs

@@ -182,6 +182,9 @@ internal ClusterConfiguration(ServerSelectionStrategy serverSelectionStrategy, s
                     if (string.IsNullOrWhiteSpace(line)) continue;
 
                     var node = new ClusterNode(this, line, origin);
+                    // Be resilient to ":0 {master,slave},fail,noaddr" nodes
+                    if (node.IsNoAddr)
+                        continue;
                     nodeLookup.Add(node.EndPoint, node);
                 }
             }
@@ -262,6 +265,8 @@ public sealed class ClusterNode :  IEquatable<ClusterNode>, IComparable<ClusterN
 
         private readonly bool isSlave;
 
+        private readonly bool isNoAddr;
+
         private readonly string nodeId, parentNodeId, raw;
 
         private readonly IList<SlotRange> slots;
@@ -291,6 +296,7 @@ internal ClusterNode(ClusterConfiguration configuration, string raw, EndPoint or
             }
             nodeId = parts[0];
             isSlave = flags.Contains("slave");
+            isNoAddr = flags.Contains("noaddr");
             parentNodeId = string.IsNullOrWhiteSpace(parts[3]) ? null : parts[3];
 
             List<SlotRange> slots = null;
@@ -339,6 +345,11 @@ public IList<ClusterNode> Children
         /// </summary>
         public bool IsSlave { get { return isSlave; } }
 
+        /// <summary>
+        /// Gets whether this node is flagged as noaddr
+        /// </summary>
+        public bool IsNoAddr { get { return isNoAddr; } }
+
         /// <summary>
         /// Gets the unique node-id of the current node
         /// </summary>