TechnitiumSoftware/DnsServer · error · DnsServerException

Failed to delete Secondary node: the specified node does not

Error message

Failed to delete Secondary node: the specified node does not exist in the Cluster.

What it means

Thrown by DeleteSecondaryNode when the provided secondaryNodeId is not found in _clusterNodes. The TryGetValue on existingClusterNodes at line 775 fails, meaning no node with that integer ID currently exists in the cluster.

Source

Thrown at DnsServerCore/Cluster/ClusterManager.cs:776

            //ask secondary node to leave the cluster
            await secondaryNode.AskSecondaryNodeToLeaveClusterAsync();

            return secondaryNode;
        }

        public ClusterNode DeleteSecondaryNode(int secondaryNodeId)
        {
            if (!ClusterInitialized)
                throw new DnsServerException("Failed to delete Secondary node: the Cluster is not initialized.");

            if (GetSelfNode().Type != ClusterNodeType.Primary)
                throw new DnsServerException("Failed to delete Secondary node: only a Primary node can delete a Secondary node from the Cluster.");

            //find existing secondary node
            IReadOnlyDictionary<int, ClusterNode> existingClusterNodes = _clusterNodes;

            if (!existingClusterNodes.TryGetValue(secondaryNodeId, out ClusterNode secondaryNode))
                throw new DnsServerException("Failed to delete Secondary node: the specified node does not exist in the Cluster.");

            if (secondaryNode.Type == ClusterNodeType.Primary)
                throw new DnsServerException("Failed to delete Secondary node: the specified node is the Cluster Primary node and cannot be deleted.");

            //delete secondary node from cluster nodes
            Dictionary<int, ClusterNode> updatedClusterNodes = new Dictionary<int, ClusterNode>(existingClusterNodes.Count - 1);

            foreach (KeyValuePair<int, ClusterNode> existingClusterNode in existingClusterNodes)
            {
                if (existingClusterNode.Key == secondaryNodeId)
                    continue;

                updatedClusterNodes[existingClusterNode.Key] = existingClusterNode.Value;
            }

            IReadOnlyDictionary<int, ClusterNode> originalValue = Interlocked.CompareExchange(ref _clusterNodes, updatedClusterNodes, existingClusterNodes);
            if (!ReferenceEquals(originalValue, existingClusterNodes))
                throw new InvalidOperationException("Failed to delete Secondary node: please try again.");

View on GitHub (pinned to d0484b6c1e)

Solutions

1. Refresh the cluster node list and pass a currently-valid secondaryNodeId.
2. Verify the node exists (_clusterNodes.ContainsKey) before calling.
3. If the node is already gone, treat it as success (idempotent delete) rather than an error.

Example fix

// before
_clusterManager.DeleteSecondaryNode(nodeId);
// after — guard against stale/missing node
if (!_clusterManager.ClusterNodes.Any(n => n.Key == nodeId))
    return; // already removed — idempotent no-op
_clusterManager.DeleteSecondaryNode(nodeId);

// Verify the node exists before deleting — treat missing as idempotent success
if (!_dnsWebService.ClusterManager.ClusterNodes.Any(n => n.Key == nodeId))
    return; // already removed
_dnsWebService.ClusterManager.DeleteSecondaryNode(nodeId);

static bool NodeExists(ClusterManager cm, int nodeId)
    => cm.ClusterNodes.Any(n => n.Key == nodeId);

try
{
    _clusterManager.DeleteSecondaryNode(nodeId);
}
catch (DnsServerException ex) when (ex.Message.Contains("does not exist in the Cluster"))
{
    // node already deleted — idempotent no-op
}

When it happens

Trigger: DeleteSecondaryNode(secondaryNodeId) is called with an ID that does not match any key in the _clusterNodes dictionary. The node may have been already deleted, or the ID is simply wrong.

Common situations: Stale UI or client state showing a node that was already removed; double-delete attempt; wrong integer ID passed; race condition where another admin removed the node between the list refresh and the delete call.

Related errors

• Failed to ask Secondary node to leave: the specified node do
• Failed to delete Secondary node: the Cluster is not initiali
• Failed to delete Secondary node: only a Primary node can del
• Failed to update Primary node: the specified Primary node ID
• At least one parameter must be provided.

AI-assisted analysis of TechnitiumSoftware/DnsServer@d0484b6c1e (2026-08-13). Data as JSON: /api/errors/935adfcebcafa9b5. Report an issue: GitHub.