Issue

• How to disable NFSv4.1 on RHEL7 based NFS server permanently?

• According to the kernel doc, we can disable v4.1 at runtime:

(From /usr/share/doc/kernel-doc-3.10.0/Documentation/filesystems/nfs/nfs41-server.txt)

NFSv4.1 Server Implementation

Server support for minorversion 1 can be controlled using the
/proc/fs/nfsd/versions control file.  The string output returned
by reading this file will contain either "+4.1" or "-4.1"
correspondingly.

Currently, server support for minorversion 1 is disabled by default.
It can be enabled at run time by writing the string "+4.1" to
the /proc/fs/nfsd/versions control file.  Note that to write this
control file, the nfsd service must be taken down.  Use your user-mode
nfs-utils to set this up; see rpc.nfsd(8)

(Warning: older servers will interpret "+4.1" and "-4.1" as "+4" and
"-4", respectively.  Therefore, code meant to work on both new and old
kernels must turn 4.1 on or off *before* turning support for version 4
on or off; rpc.nfsd does this correctly.)

• However it will not survive the server reboot and revert back to the default (v4.1 enabled).