Singularity build with fakeroot giving an invalid argument error - containers

Question

I am having some trouble with singularity on a system that I don't have sudo permissions on. Singularity is a module on this system so that other users can use it.
I am the first user trying to use it. I am trying to use --fakeroot (-f) to build a very simple container.
$ module load singularity
$ singularity --version
singularity version 3.6.4
$ cat t.def
Bootstrap: library
From: ubuntu:18.04
Stage: build
$ singularity build -f t.sif t.def
ERROR : Failed to create container process: Invalid argument
$ singularity -d build -f t.sif t.def
DEBUG [U=1013,P=8140] persistentPreRun() Singularity version: 3.6.4
DEBUG [U=1013,P=8140] persistentPreRun() Parsing configuration file /opt/singularity/3.6.4//etc/singularity/singularity.conf
DEBUG [U=1013,P=8140] handleConfDir() /home/Thomas.Robinson/.singularity already exists. Not creating.
DEBUG [U=1013,P=8140] init() Use starter binary /opt/singularity/3.6.4/libexec/singularity/bin/starter-suid
VERBOSE [U=0,P=8140] print() Set messagelevel to: 5
VERBOSE [U=0,P=8140] init() Starter initialization
DEBUG [U=0,P=8140] get_pipe_exec_fd() PIPE_EXEC_FD value: 8
VERBOSE [U=0,P=8140] is_suid() Check if we are running as setuid
VERBOSE [U=0,P=8140] priv_drop() Drop root privileges
DEBUG [U=1013,P=8140] init() Read engine configuration
DEBUG [U=1013,P=8140] init() Wait completion of stage1
VERBOSE [U=1013,P=8150] priv_drop() Drop root privileges permanently
DEBUG [U=1013,P=8150] set_parent_death_signal() Set parent death signal to 9
VERBOSE [U=1013,P=8150] init() Spawn stage 1
DEBUG [U=1013,P=8150] startup() fakeroot runtime engine selected
VERBOSE [U=1013,P=8150] startup() Execute stage 1
DEBUG [U=1013,P=8150] StageOne() Entering stage 1
VERBOSE [U=1013,P=8140] wait_child() stage 1 exited with status 0
DEBUG [U=1013,P=8140] cleanup_fd() Close file descriptor 4
DEBUG [U=1013,P=8140] cleanup_fd() Close file descriptor 5
DEBUG [U=1013,P=8140] cleanup_fd() Close file descriptor 6
DEBUG [U=1013,P=8140] init() Set child signal mask
DEBUG [U=1013,P=8140] init() Create socketpair for master communication channel
DEBUG [U=1013,P=8140] init() Create RPC socketpair for communication between stage 2 and RPC server
VERBOSE [U=1013,P=8140] user_namespace_init() Create user namespace
VERBOSE [U=1013,P=8140] pid_namespace_init() Create pid namespace
ERROR [U=1013,P=8140] init() Failed to create container process: Invalid argument
The debug build doesn't give any information about what the invalid argument is. I tried to remove one of the files, and it just told me I was missing an argument. Is there something wrong with the singularity install, my .def file, or am I doing something totally wrong?
Thanks for the help.

Answer 1

Could you check system enable unprivileged user namespace creation’.
It is not enabled by default.
Document: https://sylabs.io/guides/3.6/admin-guide/user_namespace.html#user-namespace-requirements
In my enviroment CentOS 7.4, enabled with:
sudo sh -c 'echo user.max_user_namespaces=15000 \
>/etc/sysctl.d/90-max_net_namespaces.conf'
sudo sysctl -p /etc/sysctl.d /etc/sysctl.d/90-max_net_namespaces.conf
The same issue in:
https://github.com/hpcng/singularity/issues/5585