NFS clients are not able to mount the NFS share after a reboot

NFS clients are not able to mount the NFS share after a reboot. The same share is accessible on other system's. Even on these system's, fresh mount attempts are not possible. The NFS mount command on the NFS client results in a permission denied error

Client error :

 mount: NFS-SERVER:/share failed, reason given by server: Permission denied

NFS Server Messages :

nfsserver mountd[11412]: authenticated mount request from 192.168.0.1:859 for /clients (/clients)

The main cause of this error is the nfsd file system is known to mount when the nfsd module is loaded. The nfsd filesytem is a special filesystem which provides access to the Linux NFS server. The exportfs and mountd programs (part of the nfs-utils package) expect to find this filesystem mounted at /proc/fs/nfsd. Restarting the NFS service will not mount the unmounted nfsd FS because the module is not reloaded.

Check whether the nfsd fs is mounted on the NFS server:

# cat /proc/mounts | grep nfsd

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cat /proc/mounts |grep nfsd
nfsd /proc/fs/nfsd nfsd rw,relatime 0 0

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Execute the following command on the NFS server to resolve the issue

# mount -t nfsd nfsd /proc/fs/nfsd

Try the NFS mounts now