NFS Datastore Fails to Mount with "The mount request was denied by the NFS server" Error

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• When attempting to add an NFS datastore to an ESXi host, the operation fails. The following error is observed in the VMkernel logs:
• You see the error:
  Unable to complete Sysinfo operation. Please see the VMkernel log file for more details.
• The ESXi /var/log/messages log contains warnings similar to:

  NFS: 220: Got error 2 from mount call  
  SunRPC: 1092: Destroying world  
  StorageApdHandler: APD Handle Created and Freed  
       NFS: 194: NFS mount <NFS_Server>:<NFS_Path> failed: The mount request was denied by the NFS server. Check that the export exists and that the client is permitted. 

Environment

VMware ESXi 7.x

VMware ESXi 8.x

Cause

The issue occurs due to access restrictions or misconfiguration on the NFS server. The NFS server may deny the mount request if:
The NFS export does not exist.
The ESXi host is not permitted access to the NFS share.

Resolution

1. Verify NFS Server Configuration:
   Confirm that the NFS export path exists on the NFS server.
   Ensure that the ESXi host has been granted appropriate permissions on the NFS server.
2. Validate Network Connectivity:
   Confirm that the ESXi can communicate with the NFS server.
   Use the following commands to check connectivity:
   vmkping <NFS_Server_IP>  
   nc -vz <NFS_Server_IP> 2049  
3. Check Firewall Rules and Export Settings:
   Verify that there are no firewall rules blocking the connection between the ESXi host and the NFS server.
   On the NFS server, ensure that the export configuration allows the ESXi host's IP address or subnet.
4. If the above checks do not resolve the issue, engage the storage team to review and correct the access settings on the NFS server.

Additional Information
After resolving the access issue, retry the operation to mount the NFS datastore.
To mount the NFS datastore from the ESXi CLI:
esxcli storage nfs add --host=<NFS_Server> --share=<NFS_Share_Path> --volume-name=<Datastore_Name>  

Additional Information

Troubleshooting NFS datastore connectivity issues