[systemd-devel] What's the correct way to configure encrypted volume and mount point?

[Andrei Borzenkov]

On Thu, Jan 29, 2015 at 8:31 PM, John Lane <systemd at jelmail.com> wrote:
> I am looking for some advice about configuring encrypted volumes with
> systemd that I want to open on demand (noauto).
>
> I can add entries into /etc/crypttab and /etc/fstab for the device, for
> example
>
> # <name>       <device>                                     <password>
> <options>
> data        UUID=deadbeef....                            none
> noauto
>
> and
>
> # <file system>    <dir>    <type>    <options>    <dump>    <pass>
> /dev/mapper/data /home/myuser/data ext4 noauto 0 0
>
> But the device doesn't unlock when I do
>
> $ mount /home/myuser/data
> mount: special device /dev/mapper/keyring does not exist
>
> But it does if I use
>
> $ systemctl start home-myuser-data.mount
>
> I'm guessing that "mount" doesn't effect systemd and, therefore, the
> dependency isn't actioned. But the docs for systemd.mount state that
> "configuring mount points through /etc/fstab is the preferred approach" so
> I'm wondering if there's something I missed from my crypttab or fstab
> entries?
>

No, you did not. systemd know about additional dependencies and tries
to resolve them. Plain "mount" does not know anything about them. It
is irrelevant where exactly this mount point is configured and
decsribed.

May be one day mount will forward mount request to systemd. Who knows.