Centos: systemd-journald.service misses the zfs-mount.service dependency #8060

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1. mskarbek commented on Oct 25, 2018

   

   mskarbek

   on Oct 25, 2018

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   This is not an issue for ZoL just a matter of proper configuration on your side. Simply put override file for each unit that depends on your mount point:

   [Unit]
   Requires=zfs-mount.service
   After=zfs-mount.service
   

   For journald that will be: /etc/systemd/system/systemd-journald.service.d/override.conf
2. drook commented on Oct 25, 2018

   

   drook

   on Oct 25, 2018

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   Well, you're right - yeah, that's a minor issue, but wouldn't it be great if this override.conf file was included in the centos package ?
3. mskarbek commented on Oct 25, 2018

   

   mskarbek

   on Oct 25, 2018

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   Nope, the fact that you have /var/log configured as a ZFS dataset doesn't mean that everyone has it that way. Shipping such override.conf with the package would cause more damage than good.

   👍React with 👍2Reacted by John M. Drescher and hesdago
4. drook commented on Oct 25, 2018

   

   drook

   on Oct 25, 2018

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   Same rule applies to your approach - the fact that you don't have the /var/log on a separate dataset doesn't mean everyone shouldn't have it there. In fact, most modern installers provided with ZFS-enabled OSes do configure the /var/log on a separate dataset: Solaris does, FreeBSD does.... welll, that's the end of list for now, but this pretty much means that any user migrating his habits from these OSes to Linux will want /var/log on a separate dataset (I could go much further and say that I believe everyone should have the /var/log on a separate dataset, but that would be counterproductive).

   And what harm could be done by starting journald after the zfs-mount.service ? I see none. I see that the defaults provided currently are non-universal and hard to fix by newbies.
5. mskarbek commented on Oct 25, 2018

   

   mskarbek

   on Oct 25, 2018

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   Do you ship predefined /etc/fstab? No, that's something local, generated during installation and modified after that accordingly to the changing situation. The same goes for messing with the configuration of others services, you are not packaging that, it's a matter of local requirements, specific to that concrete installation and to be provided by administrator or automation script after installation. Linux is not a native environment for ZFS, nobody expects and tests changes from ZFS besides ZoL users so comparing to the ZFS-enabled OSes is not adequate. If you are expecting such configuration to be provided automatically on a Linux installation with ZFS on root for example then it's a matter of instillator to provide that change.
6. rlaager commented on Jan 9, 2019

   

   rlaager

   on Jan 9, 2019

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   Rather than adding an override for each unit, you can make /var/log a legacy mount and put it in /etc/fstab. In this way, things lean on the built-in/default mount dependencies. Once ZFS has a systemd mount generator, it will not be necessary to use legacy mounts.

   I have this in the Ubuntu 18.04 HOWTO:
   https://github.com/zfsonlinux/zfs/wiki/Ubuntu-18.04-Root-on-ZFS

   # zfs set mountpoint=legacy rpool/var/log
   # zfs set mountpoint=legacy rpool/var/tmp
   # cat >> /etc/fstab << EOF
   rpool/var/log /var/log zfs noatime,nodev,noexec,nosuid 0 0
   rpool/var/tmp /var/tmp zfs noatime,nodev,nosuid 0 0
   EOF
   
   If you created a /tmp dataset, do the same for it:
   # zfs set mountpoint=legacy rpool/tmp
   # cat >> /etc/fstab << EOF
   rpool/tmp /tmp zfs noatime,nodev,nosuid 0 0
   EOF
   

   👍React with 👍1Reacted by Ian Campbell
7. rlaager commented on Dec 14, 2019

   

   rlaager

   on Dec 14, 2019

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   ZFS has a systemd mount generator these days.
8. rlaager

   closed this as completedon Dec 14, 2019