systemd does not start rpc.svcgssd with options given in /etc/default/nfs-kernel-server

[James Dingwall]

/etc/default/nfs-kernel-server invites you to pass additional arguments to rpc.svcgssd by populating RPCSVCGSSDOPTS, e.g.:

RPCSVCGSSDOPTS="-n"

/lib/systemd/system/rpc-svcgssd.service passes additional arguments to rpc.svcgssd from the variable $SVCGSSDARGS with the environment file set as /run/sysconfig/nfs-utils. The content of the environment file is:

PIPEFS_MOUNTPOINT=/run/rpc_pipefs
RPCNFSDARGS=" 12"
RPCMOUNTDARGS="--manage-gids --no-nfs-version 3 --no-nfs-version 2"
STATDARGS=""
RPCSVCGSSDARGS="-n"

As -n is not passed to rpc.svcgssd it does not start as my keytab does not contain an nfs/<fqdn> principal:

Aug 2 15:03:32 zombie rpc.svcgssd[24635]: ERROR: GSS-API: error in gss_acquire_cred(): GSS_S_FAILURE (Unspecified GSS failure. Minor code may provide more information) - No key table entry found matching nfs/@
Aug 2 15:03:32 zombie rpc.svcgssd[24635]: unable to obtain root (machine) credentials
Aug 2 15:03:32 zombie rpc.svcgssd[24635]: do you have a keytab entry for nfs/<your.host>@<YOUR.REALM> in /etc/krb5.keytab?
Aug 2 15:03:32 zombie systemd[1]: rpc-svcgssd.service: Control process exited, code=exited status=1
Aug 2 15:03:32 zombie systemd[1]: rpc-svcgssd.service: Failed with result 'exit-code'.
Aug 2 15:03:32 zombie systemd[1]: Failed to start RPC security service for NFS server.

# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic

# apt-cache policy nfs-kernel-server
nfs-kernel-server:
  Installed: 1:1.3.4-2.1ubuntu5
  Candidate: 1:1.3.4-2.1ubuntu5
  Version table:
 *** 1:1.3.4-2.1ubuntu5 500
        500 http://gb.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        100 /var/lib/dpkg/status