rngd read error

Timothy Murphy gayleard at eircom.net
Mon Jun 29 15:30:09 UTC 2015


When I re-boot my Fedora-21/KDE laptop
I get dozens of error lines "rngd read error" in /var/log/messages .
This has been happening for some time.
I've ignored it up to now, as it seems to have no bad consequences.
But the number of times this line is repeated seems to be increasing,
so I thought I would look into it.
Many people have asked about this error message,
but the only helpful response I have seen was in
<https://ask.fedoraproject.org/en/question/48046/boot-hangs-rngd-read-error//>,
where I read (in one of the answers):
------------------------
rngd gathers entropy from a hardware device, You don't have one, so rngd 
doesn't work. This is expected, and not related to your problem. You can do 
systemctl disable rngd with no ill effects to stop seeing the messages
------------------------

I've followed this advice, but am left wondering from what "hardware device"
rngd would "gather entropy"?

Incidentally, I read at one point that I could learn more from journalctl.
But when I run "sudo journalctl" I get an enormous number of lines,
ending with lines 262810-262850, dated March 10 (I assume this year).
Is there some way of culling journalctl?

I tried "sudo journalctl _SYSTEMD_UNIT=rngd"
but just got the response
Logs begin at Tue 2015-01-13 07:42:13 CET, 
  end at Mon 2015-06-29 17:25:30 CEST

I found "man journalctl" more or less unintelligible.
Maybe it was written by a machine?


-- 
Timothy Murphy  
gayleard /at/ eircom.net
School of Mathematics, Trinity College, Dublin




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