test ! -e "$root/var/also-nope"
test ! -e "$root/usr/nope-too"
+ # --volatile= with -U
+ touch "$root/usr/has-usr"
+ # volatile(=yes): rootfs is tmpfs, /usr/ from the OS tree is mounted read only
+ systemd-nspawn --directory="$root"\
+ --volatile \
+ -U \
+ bash -xec 'test -e /usr/has-usr; touch /usr/read-only && exit 1; touch /nope'
+ test ! -e "$root/nope"
+ test ! -e "$root/usr/read-only"
+ systemd-nspawn --directory="$root"\
+ --volatile=yes \
+ -U \
+ bash -xec 'test -e /usr/has-usr; touch /usr/read-only && exit 1; touch /nope'
+ test ! -e "$root/nope"
+ test ! -e "$root/usr/read-only"
+ # volatile=state: rootfs is read-only, /var/ is tmpfs
+ systemd-nspawn --directory="$root" \
+ --volatile=state \
+ -U \
+ bash -xec 'test -e /usr/has-usr; mountpoint /var; touch /read-only && exit 1; touch /var/nope'
+ test ! -e "$root/read-only"
+ test ! -e "$root/var/nope"
+ # volatile=overlay: tmpfs overlay is mounted over rootfs
+ systemd-nspawn --directory="$root" \
+ --volatile=overlay \
+ -U \
+ bash -xec 'test -e /usr/has-usr; touch /nope; touch /var/also-nope; touch /usr/nope-too'
+ test ! -e "$root/nope"
+ test ! -e "$root/var/also-nope"
+ test ! -e "$root/usr/nope-too"
+
# --machine=, --hostname=
systemd-nspawn --directory="$root" \
--machine="foo-bar.baz" \