[systemd-devel] Journald : from initialramfs to real root

[Thomas HUMMEL]

On 2/25/25 7:49 PM, Mantas Mikulėnas wrote:

>> But this seems to go against the fact that intitalramfs journald can
>> show intitialramfs systemd units (which dracut services are) logs, no ?
> 
> 
> No, why do you think so?

Hello,

Sorry, I had a poor understanding of how this all should fit together.
I've read doc further now.

I thought you said it logged into /run/log to some other place/mechanism 
than journald. You obviously meant the volatile /run/log/journal/ 
journal, right ?

So, indeed it makes sense now.

Still I'm curious about:

1. how one tmpfs can be handed to new root (but this is out of topic)

2. why, assuming rsyslogd uses /proc/kmsg instead of /dev/kmsg
(which you assumed too because of the format and I also assume because I 
can see with lsof rsyslogd opened /proc/kmsg + I think its imklog module 
can manage console_log_level for instance), I can still dmesg (which 
strace shows it opens /dev/kmsg) or journalctl -b and see kernel boot 
logs which should have been consumed when read through /proc/kmsg.
Or maybe rsyslogd uses SYSLOG_ACTION_READALL of syslog(2) and never 
clears the buffer ? or uses both /dev/ and /proc kmsg


Thanks again for your help and sorry for the slow catch up I showed in 
my understanding.

-- 
Thomas HUMMEL
HPC Group
Institut PASTEUR
Paris, FRANCE