F36 Change: Unit Names in Systemd Messages (Self-Contained Change proposal)

[Ben Cotton]

https://fedoraproject.org/wiki/Changes/Unit_Names_in_Systemd_Messages

== Summary ==
The default format of messages printed by systemd to the console and
the journal is changed from "Starting Frobnicating Daemon..." /
"Started Frobnicating Daemon" to "Starting frobnicator.service —
Frobnicating Daemon..." / "Started frobnicator.service — Frobnicating
Daemon".

== Owner ==
* Name: [[User:Zbyszek|Zbigniew Jędrzejewski-Szmek]]
* Email: zbyszek at in.waw.pl


== Detailed Description ==
Systemd has three message formatting modes: `description`, `name`, and
`combined`. The first uses the Description, the second uses the unit
name, and the third uses "<name> — <Description>". We currently
default to `description`, and the proposal is to change the
compile-time default to `combined`. Users can override the default by
creating a configuration file and/or specifying an override on the
kernel command line.

systemd historically used the unit Description in console and journal
status messages, just like SysV init scripts. The Description is
intended to be easy to understand, but has the downside that to
interact with the service in any way, one has to figure out what the
unit name is. Thus, for an unfamiliar service, the user would have to
grep the unit list for the description first. And for more experienced
users, the unit name is more informative than the description. People
interact with unit names when operating on units, and don't look at
the descriptions during normal system administration. Thus, for both
new and experienced users, seeing the unit name is useful. To make the
change easier to accept, we added the `combined` mode, that also
prints the description on the right.

`journalctl -o cat` (old and new):
<pre>
Started Journal Service.
Finished Load Kernel Modules.
Starting Apply Kernel Variables...
Starting Create Volatile Files and Directories...
Finished Apply Kernel Variables.
Finished Create Volatile Files and Directories.
Finished Setup Virtual Console.
Starting dracut ask for additional cmdline parameters...
Finished dracut ask for additional cmdline parameters.
Starting dracut cmdline hook...
</pre>

<pre>
Started systemd-journald.service - Journal Service.
Finished systemd-modules-load.service - Load Kernel Modules.
Finished systemd-tmpfiles-setup-dev.service - Create Static Device
Nodes in /dev.
Starting systemd-sysctl.service - Apply Kernel Variables...
Starting systemd-tmpfiles-setup.service - Create Volatile Files and
Directories...
Finished systemd-sysctl.service - Apply Kernel Variables.
Finished systemd-tmpfiles-setup.service - Create Volatile Files and Directories.
Finished systemd-vconsole-setup.service - Setup Virtual Console.
Starting dracut-cmdline-ask.service - dracut ask for additional
cmdline parameters...
Finished dracut-cmdline-ask.service - dracut ask for additional
cmdline parameters.
Starting dracut-cmdline.service - dracut cmdline hook...
</pre>

If users don't like the new default, they can use
`systemd.status-unit-format=name|description` to override the default.
It is also possible to use `bootctl systemd-efi-options
systemd.status-unit-format=name|description` on EFI systems, and
create a config file with `[Manager]
StatusUnitFormat=name|description` to pick a different setting.


== Benefit to Fedora ==
The default format of messages is more directly useful. A user can
select&amp;paste the unit name directly from a message into a command
like `systemctl status` or `journalctl -u`.

== Scope ==
* Proposal owners:
** Implement the new mode (already done, available in systemd-249).
** Flip the compile-time default in systemd.

* Other developers:
** Adjust Descriptions of their units if appropriate. For example,
firewalld.service repeats the unit name in the Description. This was
already discouraged in the systemd.unit(5) man page, but now becomes
even more visible: `rawhide systemd[1]: Starting firewalld.service -
firewalld - dynamic firewall daemon...`. The Description should be
changed to "Description=Dynamic Firewall Daemon".

* Policies and guidelines: N/A (not needed for this Change)
* Trademark approval: N/A (not needed for this Change)
* Alignment with Objectives:


== Upgrade/compatibility impact ==
There shouldn't be any. I'm making this a Change because people don't
like surprises in the default look of things. There might be some
poorly written scripts which grep for unit Descriptions.


== How To Test ==
Boot, look at `journalctl -b _PID=1`.

Optionally, disable the plymouth screen (with Esc or by removing `rhgb
quiet` on the kernel command line), and look at console messages.
Output should contain unit names and be generally readable.
Unfortunately, the console output is ellipsized to fit in 80 columns,
so the full text is not always visible.

== User Experience ==
See example output above.

== Dependencies ==
None.

== Contingency Plan ==
* Contingency mechanism: Revert the change.
* Contingency deadline: Final release, or maybe even later.
* Blocks release? No.

== Documentation ==
*
https://www.freedesktop.org/software/systemd/man/systemd-system.conf.html...
* https://github.com/systemd/systemd/commit/04d232d807


-- 
Ben Cotton
He / Him / His
Fedora Program Manager
Red Hat
TZ=America/Indiana/Indianapolis

[Matthew Miller]

On Mon, Nov 15, 2021 at 09:06:49AM -0500, Ben Cotton wrote:
>  Started Journal Service.
>  Finished Load Kernel Modules.
>  Starting Apply Kernel Variables...
>  Starting Create Volatile Files and Directories...
>  Finished Apply Kernel Variables. 
[...]
>  Started systemd-journald.service - Journal Service.
>  Finished systemd-modules-load.service - Load Kernel Modules.
>  Finished systemd-tmpfiles-setup-dev.service - Create Static Device Nodes in /dev.
>  Starting systemd-sysctl.service - Apply Kernel Variables... 
[...]

This is pretty bikesheddy, but... I find the new format hard to follow
because the service names _aren't_ easily readable, and the following
human-readable text has ragged-left-edge alignment.

Would something like

Started  Journal Service (systemd-journald.service).
Finished Load Kernel Modules (systemd-modules-load.service).
Finished Create Static Device Nodes in /dev (systemd-tmpfiles-setup-dev.service)
etc.

be possible?


-- 
Matthew Miller
<mattdm(a)fedoraproject.org&gt;
Fedora Project Leader

[przemek klosowski]

On 11/17/21 13:49, Matthew Miller wrote:
> > Finished systemd-modules-load.service - Load Kernel Modules.
> > Finished systemd-tmpfiles-setup-dev.service - Create Static Device Nodes in /dev.
> > Starting systemd-sysctl.service - Apply Kernel Variables...
> > [...]
> > Would something like
> >
> > Started  Journal Service (systemd-journald.service).
> > Finished Load Kernel Modules (systemd-modules-load.service).
> > Finished Create Static Device Nodes in /dev (systemd-tmpfiles-setup-dev.service)
> > etc.
> >
> > be possible? 
I find Matthew's version much easier to read and comprehend,
especially 
when it comes as a wall of startup text.

[Zbigniew Jędrzejewski-Szmek]

On Wed, Nov 17, 2021 at 01:49:00PM -0500, Matthew Miller wrote:
>  On Mon, Nov 15, 2021 at 09:06:49AM -0500, Ben Cotton wrote:
>  > Started Journal Service.
>  > Finished Load Kernel Modules.
>  > Starting Apply Kernel Variables...
>  > Starting Create Volatile Files and Directories...
>  > Finished Apply Kernel Variables.
>  [...]
>  > Started systemd-journald.service - Journal Service.
>  > Finished systemd-modules-load.service - Load Kernel Modules.
>  > Finished systemd-tmpfiles-setup-dev.service - Create Static Device Nodes in /dev.
>  > Starting systemd-sysctl.service - Apply Kernel Variables...
>  [...]
>  
>  This is pretty bikesheddy, but... I find the new format hard to follow
>  because the service names _aren't_ easily readable, and the following
>  human-readable text has ragged-left-edge alignment.
>  
>  Would something like
>  
>  Started  Journal Service (systemd-journald.service).
>  Finished Load Kernel Modules (systemd-modules-load.service).
>  Finished Create Static Device Nodes in /dev (systemd-tmpfiles-setup-dev.service)
>  etc.
>  
>  be possible? 
This was one of the versions proposed when we were implementing this
upstream. We ultimately chose the one proposed, primarily because
it is expected that truncation will occur e.g. on 80 char ttys,
and it is better if the description is truncated, rather than the
unit name. Also, in the 'name' format, the name is the only thing
that is displayed, and I think this is the format is the most useful.
It is then nice that the 'combined' format is an extension of 'name',
and not something completely different.

On the console, the unit name part is highlighted, so it's not so
wall-of-texty as in the example I pasted.

Zbyszek