Voir :

• https://www.baeldung.com/linux/bind-mounts
• https://blog.stephane-robert.info/docs/admin-serveurs/linux/namespaces/
• https://github.com/docker/for-mac/issues/3431
• https://abdelouahabmbarki.com/linux-mount-namespaces-a-closer-look-at-isolated-file-system-views/
• https://unix.stackexchange.com/questions/710971/how-do-you-get-the-child-pid-of-unshare-when-using-fork-for-nsenter-t-pid
• https://www.gabriel.urdhr.fr/2022/12/03/entering-podman-namespaces/
• https://unix.stackexchange.com/questions/710971/how-do-you-get-the-child-pid-of-unshare-when-using-fork-%20for-nsenter-t-pid
• https://connect.ed-diamond.com/GNU-Linux-Magazine/glmf-247/a-la-decouverte-des-namespaces-mount-et-uts
• https://superuser.com/questions/165116/mount-dev-proc-sys-in-a-chroot-environment
• https://lwn.net/Articles/690679/
• https://stackoverflow.com/questions/56254904/why-can-a-process-launched-with-unshare-m-affect-the-mounts-in-the-host
• https://www.redhat.com/en/blog/mount-namespaces
• https://people.kernel.org/brauner/mounting-into-mount-namespaces
• https://unix.stackexchange.com/questions/594545/can-i-move-mount-to-other-mount-namespace

findmnt -o TARGET,PROPAGATION /opt
 
cat /proc/1/mountinfo

$ podman pull docker.io/hadolint/hadolint
WARN[0001] "/" is not a shared mount, this could cause issues or missing mounts with rootless containers

Solution

sudo mount --make-shared /