Hello,
Just hit that issue on Debian Buster so it is still relevant, but with the systemd erra, I went for a different solution:
mkdir /etc/systemd/system/nfs-server.service.decho -e "[Service]\nExecStartPre=/bin/sh -c '/bin/echo 10 > /proc/fs/nfsd/nfsv4leasetime'" > /etc/systemd/system/nfs-server.service.d/nfsv4leasetime-10secs.conf
systemctl daemon-reload systemctl restart nfs-kernel-server cat /proc/fs/nfsd/nfsv4leasetime Best regards, Adam.