Bug#758808: Additional info

[Miloslav Semler]

I dont know too much about systemd, but it is strange that depending 
service can fail if has set shorter timeout than service which depends on:

[Unit]
SourcePath=/etc/fstab
Documentation=man:fstab(5) man:systemd-fstab-generator(8)
Before=local-fs.target
RequiresOverridable=systemd-fsck at dev-mapper-vol_md2\x2dlv_var_lib.service
After=systemd-fsck at dev-mapper-vol_md2\x2dlv_var_lib.service

content of dir local-fs.target.wants:

**** lvm2-activation-early.service
[Unit]
Description=Activation of LVM2 logical volumes
Documentation=man:lvm(8) man:vgchange(8)
DefaultDependencies=no
After=systemd-udev-settle.service
Before=cryptsetup.target local-fs.target shutdown.target
Wants=systemd-udev-settle.service

[Service]
ExecStart=/sbin/lvm vgchange -aay --sysinit
Type=oneshot

[Install]
WantedBy=local-fs.target

*****

[Unit]
Description=Activation of LVM2 logical volumes
Documentation=man:lvm(8) man:vgchange(8)
DefaultDependencies=no
After=lvm2-activation-early.service cryptsetup.target
Before=local-fs.target shutdown.target
Wants=systemd-udev-settle.service

[Service]
ExecStart=/sbin/lvm vgchange -aay --sysinit
Type=oneshot

[Install]
WantedBy=local-fs.target

**** content of udev-settle-service, which wants

[Unit]
Description=udev Wait for Complete Device Initialization
Documentation=man:udev(7) man:systemd-udevd.service(8)
DefaultDependencies=no
Wants=systemd-udevd.service
After=systemd-udev-trigger.service
Before=sysinit.target
ConditionPathIsReadWrite=/sys

[Service]
Type=oneshot
TimeoutSec=300
RemainAfterExit=yes
ExecStart=/bin/udevadm settle

If I set timeout 60 sec, system starts (after timeout of udev-settle) 
normally, otherwise both services mounting /var/lib and /mnt/data fails 
and system goes to failsafe mode.

So question is How is this possible? Service waits and timeouts on 
something on which does not depend? Or depend... so how it is possible 
systemd starts this service after failure of service which depends on.


Miloslav
> Am 17.01.2016 um 20:18 schrieb Miloslav Semler:
>> Finally,
>> I found that if I shorten timeout of systemd-udev-settle.service from
>> 180s to 60s, systems boot to normal mode (althrough this udev service
>> rise an error).
>>
>> So please fix timeouts in this package to 60sec otherwise udev mount of
>> lvm drive can fail.
> I don't see how this would be a proper fix.
> So far we don't know what the underlying problem is and how to reproduce
> it, which is a prerequisite for fixing it.
>
>