Windows Failover cluster

Hi Sarath, I am Henry and I want to share with you about this issue.

I've encountered a few cases with the same issue you're facing. Before diving into troubleshooting and analyzing cluster logs as a last resort, please make sure that the prerequisites for cluster setup are in place. You can refer to this guide: Create a Failover Cluster (Windows Admin Center)

Alternatively, follow the checklist below:

1. DNS Issues: Ensure that the Cluster Name Object (CNO) and all node hostnames resolve correctly to their IP addresses across all nodes. Verify A and PTR records, ensure DNS server consistency, and flush DNS caches.

2. Firewalls: Verify that Windows Defender Firewall or any third-party firewall isn’t blocking required cluster ports. Ensure required ports are open. You can reference Cluster Service:

• RPC: 135
• SMB: 445
• Cluster: 3343
• RPC dynamic ports: 49152–65535

Try temporarily disabling the firewall to isolate the issue.

3. Network Connectivity: Review physical and logical network connections, including heartbeat and cluster networks. Confirm all adapters are functioning and nodes can communicate with each other.

4. Cluster Service Health: Make sure the "Cluster Service" is stable on all nodes. Check Event Logs for any warnings or errors.

5. Permissions: Ensure your user account has the proper administrative privileges on each node and for the cluster object in Active Directory.

6. Run Cluster Validation Report Execute the validation report from a functioning node to detect hardware, network, or software configuration issues.

If the issue persists after these checks, please reproduce it across three nodes.from one working node and the two affected nodes. Run this PowerShell command as Administrator: Get-ClusterLog -Node <NodeName> -TimeSpan 5

Zip the resulting log files and share them with me — I’ll help review them.