Bug#958390: systemd: systemctl ignores soft links in /etc/systemd/system at boot

Erich Minderlein erich.minderlein at edhec.com
Wed Apr 22 11:10:18 BST 2020


Hi Michael

Your proposal to tamper with initramfs is off the target.
initramfs is well before PID 1. There ist no problem before PID 1.
It can only hurt or damage something.

systemctl list-dependencies my.timer
my.timer
● └─sysinit.target
●   ├─apparmor.service
●   ├─dev-hugepages.mount
●   ├─dev-mqueue.mount
●   ├─keyboard-setup.service
●   ├─kmod-static-nodes.service
●   ├─proc-sys-fs-binfmt_misc.automount
●   ├─sys-fs-fuse-connections.mount
●   ├─sys-kernel-config.mount
●   ├─sys-kernel-debug.mount
●   ├─systemd-ask-password-console.path
●   ├─systemd-binfmt.service
●   ├─systemd-hwdb-update.service
●   ├─systemd-journal-flush.service
●   ├─systemd-journald.service
●   ├─systemd-machine-id-commit.service
●   ├─systemd-modules-load.service
●   ├─systemd-random-seed.service
●   ├─systemd-sysctl.service
●   ├─systemd-sysusers.service
●   ├─systemd-timesyncd.service
●   ├─systemd-tmpfiles-setup-dev.service
●   ├─systemd-tmpfiles-setup.service
●   ├─systemd-udev-trigger.service
●   ├─systemd-udevd.service
●   ├─systemd-update-utmp.service
●   ├─cryptsetup.target
●   ├─local-fs.target
●   │ ├─-.mount
●   │ ├─home.mount
●   │ ├─systemd-fsck-root.service
●   │ ├─systemd-remount-fs.service
●   │ ├─tmp.mount
●   │ └─var.mount
●   └─swap.target
●     └─dev-disk-by\x2duuid-xxxxxxxx....xxxxxxxxxxxxxxxxx.swap

When you go down the tree, you find
level -1 sysinit.target
level -2 local-fs.target
level -3 home.mount

S systemd knows, that it must provide the mount of home before scanning 
my.timer

I suggest you reopen the bug, because you have a race condition there, 
which redhat seemss to have solved.


after some reading I see that two mounts may be needed :

systemctl list-units --type=mount --all
UNIT                          LOAD   ACTIVE   SUB     DESCRIPTION
-.mount                       loaded active   mounted Root Mount
dev-hugepages.mount           loaded active   mounted Huge Pages File System
dev-mqueue.mount              loaded active   mounted POSIX Message 
Queue File System
home.mount                    loaded active   mounted /home
proc-sys-fs-binfmt_misc.mount loaded active   mounted Arbitrary 
Executable File Formats File System
run-user-0.mount              loaded active   mounted /run/user/0
run-user-1000.mount           loaded active   mounted /run/user/1000
sys-fs-fuse-connections.mount loaded inactive dead    FUSE Control File 
System
sys-kernel-config.mount       loaded inactive dead    Kernel 
Configuration File System
sys-kernel-debug.mount        loaded active   mounted Kernel Debug File 
System
tmp.mount                     loaded active   mounted /tmp
var.mount                     loaded active   mounted /var

That is the home mount and may be the user-1000-mount.

btw I have done som more testing with systemd.

There is nothing in
/etc/initramfs-tools/scripts/local-premount, except . and  .. , :-)
as they are all in fstab , seems to be a race .

I have now added
RequireMountsFor=/home into the service files.
The problem continues.

I think, you have been too fast in closing this bug.
Initramfs is another site.
If I goof something in initramfs , then it will be gone with the next 
kernel install.
debian 10.3 has nothing inside the initramfs script section,
I could not even copy and adopt a script.
systemd provides a job home.mount and is solely responsible for the 
complete ordered startup through all runlevel. I expect this .
that the file system is mounted before any job wants to accces it.

My fix of this problem is to go back to cron and sysvinit, if systemd is 
relying  on the customer to sort, what the vendor of the package has not 
achieved. So devuan is the the solution , because debian has integrated 
systemnd so much taht there is no way back





Am 21.04.20 um 14:01 schrieb Michael Biebl:
> Am 21.04.20 um 13:55 schrieb Michael Biebl:
>> Control: tags -1 + moreinfo
>> Control: severity -1 normal
>>
>> Am 21.04.20 um 13:23 schrieb Erich Minderlein:
>>
>>> $HOME/location/of/app/etc/systemd/system/config.*
>>
>> Is that on a separate partition that has to be mounted during boot to
>> make it accessible?
> 
> systemd itself should have no problems with using symlinks, fwiw.
> 
> My guess is, that your $HOME/location/of/app/etc/systemd/system/
> is not available when systemd is started during boot, so those files are
> inaccessible. This obviously can't work.
> You either need to move those files to a location which resides on your
> / partition or pre-mount /home in your initramfs before systemd is started.
> 

-- 
mit freundlichen Grüßen
with the beste regards

cordialement

Erich |\/|inderlei|\|
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