Make systemd debug shell usable again

Question

Specifying systemd.debug-shell=1 as kernel parameter kind of works: I can switch via Alt+F9 to a shell when systemd boot hangs.

But this shell is quite impossible because an animated

[ ***  ] A start job is running for Create Volatile Files and 
        Directories (4min 23s / no limit)

banner is destroying my prompt and command line output.

Thus, my question: how do I disable this obstructing systemd output in my shell tty9?

I'm ok with it being displayed in tty1, i.e. the main console - but as-is, it makes the systemd debug shell unusable.

This is the systemd under Fedora 29.

Answer 1

One way is to also set systemd.show_status as kernel parameter. For example, in total:

systemd.debug-shell=1 systemd.show_status=false

This makes the systemd debug shell usable again.

However, it kills all systemd boot console output, not just obstructing animations. Perhaps there is a better way - say - tell systemd somehow to just print to a certain tty.

The hanging jobs can be displayed via:

# systemctl list-jobs | grep running

Answer 2

If you add the boot option console=tty1, it should keep the systemd output on tty1.

That said, I think systemd.show_status=false is closer to what you asked for.

console=tty1 will also keep kernel messages on tty1.[*] So you could miss useful warnings or error messages. If the kernel crashes completely, it could log very useful information to tty1, but you will not be able to switch back to see it. (To be fair, you can have the same problem once you are using a graphical interface).

---

[*] Linux: Difference between /dev/console , /dev/tty and /dev/tty0

Answer 3

the inserted return; will fix the garbled F9 console in systemD :

static void manager_print_jobs_in_progress(Manager *m) {
    _cleanup_free_ char *job_of_n = NULL;
    Iterator i;
    Job *j;
    unsigned counter = 0, print_nr;
    char cylon[6 + CYLON_BUFFER_EXTRA + 1];
    unsigned cylon_pos;
    char time[FORMAT_TIMESPAN_MAX], limit[FORMAT_TIMESPAN_MAX] = "no limit";
    uint64_t x;
    return;
    assert(m);

after this, there will no longer be that stop-job notification but you can always look up the journal entries. Maybe one can find the waiting time somewhere too. see dreaded cylon patched out with more details.

Feel free to ask to reopen the OP titled: "fix dreaded “A stop job is running” cylon-animation garbling systemd.debug_shell on Alt-F9" which was redirected from view. No point in a "duplication" yet again. This seems progressively unworkable.