[Unit]
Description=Snapshot %i container
Requisite=systemd-nspawn@%i.service
Wants=mnt-containers.mount
After=systemd-nspawn@%i.service mnt-containers.mount

[Service]
Type=oneshot
ExecStartPre=/usr/bin/machinectl stop %i
# Hereunder is a bit gross, but we need to make sure container is entirely stopped / 5 sec should be sufficient, but we have a problem with mail container; perhaps this sleep is too late anyway...
ExecStart=/usr/bin/bash -c 'sleep 10 && /usr/bin/btrfs subvolume snapshot -r /mnt/containers/%i/current /mnt/containers/%i/$$(date +%%Y%%m%%d)'
# As we now get random issues post snap (containers do not always restart...), we add another sleep... Real gros...
#ExecStartPost=/usr/bin/machinectl start %i
ExecStartPost=/usr/bin/bash -c 'sleep 10 && /usr/bin/machinectl start %i'