Let's make a basic Singularity file system containing certificates at the place many programs expect them to be, i.e. /etc/ssl:
$ guix pack -S /etc/ssl=etc/ssl --format=squashfs bash nss-certs /gnu/store/mxyc56nsrcgcclvm5qsz5c9fkqwdswpw-bash-nss-certs-squashfs-pack.gz.squashfs There is no error message concerning the symlink, but it's not recorded either: $ guix shell squashfs-tools -- unsquashfs -l /gnu/store/mxyc56nsrcgcclvm5qsz5c9fkqwdswpw-bash-nss-certs-squashfs-pack.gz.squashfs | grep -v /gnu/store squashfs-root squashfs-root/.empty squashfs-root/.empty_1 squashfs-root/.singularity.d squashfs-root/.singularity.d/actions squashfs-root/.singularity.d/env squashfs-root/.singularity.d/env/90-environment.sh squashfs-root/bin squashfs-root/dev squashfs-root/gnu squashfs-root/gnu/.empty squashfs-root/home squashfs-root/proc squashfs-root/sys What *does* work is: $ guix pack -S /etc=etc --format=squashfs bash nss-certs which makes me suspect that linking /etc/ssl fails because there is no /etc in the file system, but I don't much about squashfs, so maybe I am wrong. Cheers, Konrad