Error building container using apptainer built without suid

[adnan-umich]

Version of Apptainer

apptainer version 1.3.1

Expected behavior

Since I built apptainer without requiring suid, I expected this to be build without using fakeroot.

Actual behavior

Does not build:

apptainer build --ignore-subuid --fakeroot my_container.sif test.def
INFO: User not listed in /etc/subuid, trying root-mapped namespace
INFO: fakeroot command not found
INFO: Installing some packages may fail
INFO: Starting build...
INFO: Skipping GPG Key Import
FATAL: While performing build: conveyor failed to get: while copying pseudo devices: while creating /tmp/build-temp-535427745/rootfs/dev/null: operation not permitted

Steps to reproduce this behavior

apptainer build --ignore-subuid --fakeroot my_container.sif test.def

What OS/distro are you running

NAME="Red Hat Enterprise Linux"
VERSION="8.6 (Ootpa)"

How did you install Apptainer

From source
./mconfig --without-suid -b ./buildtree -p ${PREFIX} > ${logfile} 2>&1

[DrDaveD]

You apparently didn't follow the compilation instructions, because the fakeroot command is not found. That's one of the required packages and is needed if /etc/subuid is not set up (or ignored).