[systemd-devel] Antw: [EXT] Re: successful mount starts a service - how?

[lejeczek]

On 19/01/2021 07:50, Ulrich Windl wrote:
>>>> Andrei Borzenkov <arvidjaar at gmail.com> schrieb am 19.01.2021 um 06:30 in
> Nachricht <3a365c71-004e-031e-4153-80c376d80838 at gmail.com>:
>> 19.01.2021 04:00, lejeczek пишет:
>>> hi guys.
>>>
>>> I'm fiddling with it but have run out of options/ideas.
>>> What I would like to have is systemd starts a service when a device, in
>>> my case a crypt-luks device, gets mounted which mount would happen by
>>> manual 'cryptsetup open'
>> I am not aware that "cryptsetup open" mounts anything. I do not even see
>> any option to specify mount point in its invocation. Please show exact
>> command you are using that "mounts" encrypted container.
> But it will make some device (/dev/mapper) to appear.
I'm on centos Stream with systemd 239 (239-43.el8)
OS after boot:
1)
-> $ systemctl status -l devs.mount
● devs.mount - /devs
    Loaded: loaded (/etc/fstab; generated)
    Active: inactive (dead)
     Where: /devs
      What: /dev/mapper/luks-devs
      Docs: man:fstab(5)
            man:systemd-fstab-generator(8)

Jan 19 10:24:45 swir.private.pawel systemd[1]: Dependency 
failed for /devs.
Jan 19 10:24:45 swir.private.pawel systemd[1]: devs.mount: 
Job devs.mount/start failed with result 'dependency'.
2)
-> $ cryptsetup open /dev/mapper/cl_swir-devs luks-devs
3)
-> $ systemctl status -l devs.mount
● devs.mount - /devs
    Loaded: loaded (/etc/fstab; generated)
    Active: active (mounted) since Tue 2021-01-19 10:27:09 
GMT; 48s ago
     Where: /devs
      What: /dev/mapper/luks-devs
...
In fstab:
/dev/mapper/luks-devs     /devs                   ext4 
context="system_u:object_r:root_t:s0",nofail,noatime,nobarrier,noatime,x-systemd.device-timeout=3s 
0 2

Crypt-luks device got mounted without me doing only no. 2. 
and which is fantastic. Here systemd wisdom does something 
which us users would do but as a result do not have to.

Now, how to "bind" a sevice to "that" so such a service 
would wait for and then auto start(but also stop when device 
is umounted)?
I've tried in such a service' unit a variations of these:

After=devs.mount
BindsTo=devs.mount
PartOf=devs.mount
RequiresMountsFor=/devs

But now I've run out of ideas.

many thanks, L

>>> I see when that manual action takes place then systemd changes status of
>>> a home.mount (which is in fstab) to "active" - and it's here where I
>>> hope systemd would auto-start a service.
>>> Is such a "simple" thing possible?
>>> many thanks, L
>>> _______________________________________________
>>> systemd-devel mailing list
>>> systemd-devel at lists.freedesktop.org
>>> https://lists.freedesktop.org/mailman/listinfo/systemd-devel
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