Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss
Bug#846381: avahi-daemon: cups frequently forgets about all printers untils restarting avahi-daemon
119 views
Skip to first unread message
Helmut Grohne
Nov 30, 2016, 3:10:03 PM11/30/16
to
Package: avahi-daemon
Version: 0.6.31-5
Control: affects -1 cups-daemon
Since Debian jessie, cups uses avahi to broadcast its printers to the
local network. I have a jessie cups with a few printers and publish them
via avahi. Now I am seeing a little weird behaviour on client systems:
After booting their cups daemons know about the broadcasted printers,
but after some time (usually a few times a day) they forget. I have no
clue what causes the client cups to forget about all network printers,
but after issuing "service avahi-daemon restart" on the client machine,
all the printers are back. Restarting something else (such as cups)
doesn't get me the printers back instead. This lets me conclude that
avahi-daemon somehow is the cause. I am observing this with both jessie
and unstable client systems, so stretch is affected. The
avahi-daemon.conf is pretty much the default with the exception of
setting disable-publishing=yes on all client systems. I have no idea how
to reliably trigger this bug (beyond waiting a day). Before and after
restarting avahi-daemon, the output of "avahi-browse -at" looks no
different (i.e. printers always show up there).
I understand that this bug description is quite vague. Still, it is
fairly annoying and as it happens on multiple systems some of which are
pretty close to defaults, I believe still believe it to be a bug. I
already spent considerable time trying to diagnose it and intend to do
further diagnosis if someone can provide hints as to what to check. It
might even be a cups bug. Please reassign as appropriate.
Thanks in advance
Helmut
Version: 0.6.31-5
Control: affects -1 cups-daemon
Since Debian jessie, cups uses avahi to broadcast its printers to the
local network. I have a jessie cups with a few printers and publish them
via avahi. Now I am seeing a little weird behaviour on client systems:
After booting their cups daemons know about the broadcasted printers,
but after some time (usually a few times a day) they forget. I have no
clue what causes the client cups to forget about all network printers,
but after issuing "service avahi-daemon restart" on the client machine,
all the printers are back. Restarting something else (such as cups)
doesn't get me the printers back instead. This lets me conclude that
avahi-daemon somehow is the cause. I am observing this with both jessie
and unstable client systems, so stretch is affected. The
avahi-daemon.conf is pretty much the default with the exception of
setting disable-publishing=yes on all client systems. I have no idea how
to reliably trigger this bug (beyond waiting a day). Before and after
restarting avahi-daemon, the output of "avahi-browse -at" looks no
different (i.e. printers always show up there).
I understand that this bug description is quite vague. Still, it is
fairly annoying and as it happens on multiple systems some of which are
pretty close to defaults, I believe still believe it to be a bug. I
already spent considerable time trying to diagnose it and intend to do
further diagnosis if someone can provide hints as to what to check. It
might even be a cups bug. Please reassign as appropriate.
Thanks in advance
Helmut
Brian Potkin
Dec 31, 2017, 8:00:02 PM12/31/17
to
tags 846381 moreinfo
thanks
Thanks you for your report, Helmut.
On Wed 30 Nov 2016 at 20:57:01 +0100, Helmut Grohne wrote:
> Package: avahi-daemon
> Version: 0.6.31-5
> Control: affects -1 cups-daemon
>
> Since Debian jessie, cups uses avahi to broadcast its printers to the
> local network. I have a jessie cups with a few printers and publish them
> via avahi. Now I am seeing a little weird behaviour on client systems:
> After booting their cups daemons know about the broadcasted printers,
> but after some time (usually a few times a day) they forget. I have no
What are the symptoms? How do you know that the printing system does
not see the remote broadcasted printers on the clients?
> clue what causes the client cups to forget about all network printers,
> but after issuing "service avahi-daemon restart" on the client machine,
> all the printers are back. Restarting something else (such as cups)
> doesn't get me the printers back instead. This lets me conclude that
> avahi-daemon somehow is the cause. I am observing this with both jessie
> and unstable client systems, so stretch is affected. The
cups-browsed browses the mdns broadcasts and makes the remote printers
available to applications.
> avahi-daemon.conf is pretty much the default with the exception of
> setting disable-publishing=yes on all client systems. I have no idea how
> to reliably trigger this bug (beyond waiting a day). Before and after
> restarting avahi-daemon, the output of "avahi-browse -at" looks no
> different (i.e. printers always show up there).
Being able to reproduce behaviour is always a plus and, in some cases,
a necessity.
> I understand that this bug description is quite vague. Still, it is
> fairly annoying and as it happens on multiple systems some of which are
> pretty close to defaults, I believe still believe it to be a bug. I
> already spent considerable time trying to diagnose it and intend to do
> further diagnosis if someone can provide hints as to what to check. It
> might even be a cups bug. Please reassign as appropriate.
First things first. Are you still experiencing this behaviour on an
up-to-date unstable/testing system?
thanks
Thanks you for your report, Helmut.
On Wed 30 Nov 2016 at 20:57:01 +0100, Helmut Grohne wrote:
> Package: avahi-daemon
> Version: 0.6.31-5
> Control: affects -1 cups-daemon
>
> Since Debian jessie, cups uses avahi to broadcast its printers to the
> local network. I have a jessie cups with a few printers and publish them
> via avahi. Now I am seeing a little weird behaviour on client systems:
> After booting their cups daemons know about the broadcasted printers,
> but after some time (usually a few times a day) they forget. I have no
not see the remote broadcasted printers on the clients?
> clue what causes the client cups to forget about all network printers,
> but after issuing "service avahi-daemon restart" on the client machine,
> all the printers are back. Restarting something else (such as cups)
> doesn't get me the printers back instead. This lets me conclude that
> avahi-daemon somehow is the cause. I am observing this with both jessie
> and unstable client systems, so stretch is affected. The
available to applications.
> avahi-daemon.conf is pretty much the default with the exception of
> setting disable-publishing=yes on all client systems. I have no idea how
> to reliably trigger this bug (beyond waiting a day). Before and after
> restarting avahi-daemon, the output of "avahi-browse -at" looks no
> different (i.e. printers always show up there).
a necessity.
> I understand that this bug description is quite vague. Still, it is
> fairly annoying and as it happens on multiple systems some of which are
> pretty close to defaults, I believe still believe it to be a bug. I
> already spent considerable time trying to diagnose it and intend to do
> further diagnosis if someone can provide hints as to what to check. It
> might even be a cups bug. Please reassign as appropriate.
up-to-date unstable/testing system?
Helmut Grohne
Jan 1, 2018, 7:50:03 AM1/1/18
to
Control: tags -1 - moreinfo
On Mon, Jan 01, 2018 at 12:46:47AM +0000, Brian Potkin wrote:
> Thanks you for your report, Helmut.
Thanks for looking into this.
> On Wed 30 Nov 2016 at 20:57:01 +0100, Helmut Grohne wrote:
> > Since Debian jessie, cups uses avahi to broadcast its printers to the
> > local network. I have a jessie cups with a few printers and publish them
> > via avahi. Now I am seeing a little weird behaviour on client systems:
> > After booting their cups daemons know about the broadcasted printers,
> > but after some time (usually a few times a day) they forget. I have no
>
> What are the symptoms? How do you know that the printing system does
> not see the remote broadcasted printers on the clients?
When printers are broadcasted, client cups systems create
/etc/cups/ppd/<something>.ppd for each remote printer. These files exist
after booting and then vanish. Another way to diagnose the presence of
the issue is running "lpstat -a". After boot, it lists all the printers,
but after a while, the output becomes "lpstat: No destinations added."
When I try to print something (e.g. using evince), I am presented with
an empty printer list. Then I restart avahi-daemon on the client system
and the files are back and "lpstat -a" gives a printer list again until
it forgets again.
> First things first. Are you still experiencing this behaviour on an
> up-to-date unstable/testing system?
Yes. I see this behaviour on stretch and sid.
Is there anything else I can check? Maybe trace something? Turn on some
debug logging somewhere? The issue is sufficiently annoying that I am
willing to put some time into it.
Helmut
On Mon, Jan 01, 2018 at 12:46:47AM +0000, Brian Potkin wrote:
> Thanks you for your report, Helmut.
> On Wed 30 Nov 2016 at 20:57:01 +0100, Helmut Grohne wrote:
> > Since Debian jessie, cups uses avahi to broadcast its printers to the
> > local network. I have a jessie cups with a few printers and publish them
> > via avahi. Now I am seeing a little weird behaviour on client systems:
> > After booting their cups daemons know about the broadcasted printers,
> > but after some time (usually a few times a day) they forget. I have no
>
> What are the symptoms? How do you know that the printing system does
> not see the remote broadcasted printers on the clients?
/etc/cups/ppd/<something>.ppd for each remote printer. These files exist
after booting and then vanish. Another way to diagnose the presence of
the issue is running "lpstat -a". After boot, it lists all the printers,
but after a while, the output becomes "lpstat: No destinations added."
When I try to print something (e.g. using evince), I am presented with
an empty printer list. Then I restart avahi-daemon on the client system
and the files are back and "lpstat -a" gives a printer list again until
it forgets again.
> First things first. Are you still experiencing this behaviour on an
> up-to-date unstable/testing system?
Is there anything else I can check? Maybe trace something? Turn on some
debug logging somewhere? The issue is sufficiently annoying that I am
willing to put some time into it.
Helmut
Brian Potkin
Jan 1, 2018, 11:00:03 AM1/1/18
to
On Mon 01 Jan 2018 at 13:44:15 +0100, Helmut Grohne wrote:
> Control: tags -1 - moreinfo
>
> On Mon, Jan 01, 2018 at 12:46:47AM +0000, Brian Potkin wrote:
> > Thanks you for your report, Helmut.
>
> Thanks for looking into this.
>
> > On Wed 30 Nov 2016 at 20:57:01 +0100, Helmut Grohne wrote:
> > > Since Debian jessie, cups uses avahi to broadcast its printers to the
> > > local network. I have a jessie cups with a few printers and publish them
> > > via avahi. Now I am seeing a little weird behaviour on client systems:
> > > After booting their cups daemons know about the broadcasted printers,
> > > but after some time (usually a few times a day) they forget. I have no
> >
> > What are the symptoms? How do you know that the printing system does
> > not see the remote broadcasted printers on the clients?
>
> When printers are broadcasted, client cups systems create
> /etc/cups/ppd/<something>.ppd for each remote printer. These files exist
> after booting and then vanish. Another way to diagnose the presence of
cups-browsed creates the PPDs.
> Control: tags -1 - moreinfo
>
> On Mon, Jan 01, 2018 at 12:46:47AM +0000, Brian Potkin wrote:
> > Thanks you for your report, Helmut.
>
> Thanks for looking into this.
>
> > On Wed 30 Nov 2016 at 20:57:01 +0100, Helmut Grohne wrote:
> > > Since Debian jessie, cups uses avahi to broadcast its printers to the
> > > local network. I have a jessie cups with a few printers and publish them
> > > via avahi. Now I am seeing a little weird behaviour on client systems:
> > > After booting their cups daemons know about the broadcasted printers,
> > > but after some time (usually a few times a day) they forget. I have no
> >
> > What are the symptoms? How do you know that the printing system does
> > not see the remote broadcasted printers on the clients?
>
> When printers are broadcasted, client cups systems create
> /etc/cups/ppd/<something>.ppd for each remote printer. These files exist
> after booting and then vanish. Another way to diagnose the presence of
> the issue is running "lpstat -a". After boot, it lists all the printers,
> but after a while, the output becomes "lpstat: No destinations added."
> When I try to print something (e.g. using evince), I am presented with
> an empty printer list. Then I restart avahi-daemon on the client system
> and the files are back and "lpstat -a" gives a printer list again until
> it forgets again.
latter is not running, it browses the Bonjour broadcasts of servers and
printers directly, just as avahi-browse does.
> > First things first. Are you still experiencing this behaviour on an
> > up-to-date unstable/testing system?
>
> Yes. I see this behaviour on stretch and sid.
Let's see whether cups-browsed has any connection with the issue. Stop
it running and bring up evince. Its print dialog should show the remote
printers it gets from mdns broadcasts. You relate the printers disappear
a few times a day, so we shouldn't have to wait too long to see whether
it happens in this situation. BTW, is there any discernable pattern to
the behaviour? Time of day, time interval etc?
> Is there anything else I can check? Maybe trace something? Turn on some
> debug logging somewhere? The issue is sufficiently annoying that I am
> willing to put some time into it.
for clues with "avahi", "audit", SIGTERM (and anything else you can
think of).
Cheers,
Brian.
Helmut Grohne
Jan 2, 2018, 4:20:02 AM1/2/18
to
On Mon, Jan 01, 2018 at 03:47:04PM +0000, Brian Potkin wrote:
> evince can get remote printer information from cups-browsed but, if the
> latter is not running, it browses the Bonjour broadcasts of servers and
> printers directly, just as avahi-browse does.
I cannot confirm the described behaviour.
> evince can get remote printer information from cups-browsed but, if the
> latter is not running, it browses the Bonjour broadcasts of servers and
> printers directly, just as avahi-browse does.
> > > First things first. Are you still experiencing this behaviour on an
> > > up-to-date unstable/testing system?
> >
> > Yes. I see this behaviour on stretch and sid.
>
> I am working with sid. Are you using AppArmor on Stretch?
close to a standard installation. I haven't fiddled with it much.
The sid system certainly isn't using AppArmor and could have a few
oddities: It was installed as potato and upgraded since.
> Let's see whether cups-browsed has any connection with the issue. Stop
> it running and bring up evince. Its print dialog should show the remote
> printers it gets from mdns broadcasts. You relate the printers disappear
> a few times a day, so we shouldn't have to wait too long to see whether
> it happens in this situation. BTW, is there any discernable pattern to
> the behaviour? Time of day, time interval etc?
are deleted. lpstat does not know them anymore and they disappear from
the evince print dialog (or don't show up there if I restart evince).
When cups-browsed is started again, the printers in evince, the ppd
files and the lpstat output is back again pretty much immediately.
Concerning the timing, I looked hard before filing the bug report. Log
rotation was something obvious to correlate it to, but without luck. The
waiting time seems exponentially distributed to me. Sometimes I had it
multiple times within an hour other times a day went by without.
When I ran the whole thing under strace, it didn't happen within 12h.
> Thanks for the offer. Have a good look at what journalctl says. Search
> for clues with "avahi", "audit", SIGTERM (and anything else you can
> think of).
some more logging to get useful things here. Just what should I enable?
The manual page of avahi-daemon.conf is pretty scarce on debugging
options. cups-browsed logging is pretty much off by default and when you
enable it you only see the fact that printers get removed, not why.
You see, this issue is not easy to debug. I hope you can bear with me.
Helmut
Brian Potkin
Jan 2, 2018, 1:00:03 PM1/2/18
to
On Tue 02 Jan 2018 at 10:13:01 +0100, Helmut Grohne wrote:
> On Mon, Jan 01, 2018 at 03:47:04PM +0000, Brian Potkin wrote:
> > evince can get remote printer information from cups-browsed but, if the
> > latter is not running, it browses the Bonjour broadcasts of servers and
> > printers directly, just as avahi-browse does.
>
> I cannot confirm the described behaviour.
The print dialog is empty when cups-browsed is stopped? Mystifying! GTK+
> On Mon, Jan 01, 2018 at 03:47:04PM +0000, Brian Potkin wrote:
> > evince can get remote printer information from cups-browsed but, if the
> > latter is not running, it browses the Bonjour broadcasts of servers and
> > printers directly, just as avahi-browse does.
>
> I cannot confirm the described behaviour.
uses the avahi library to list printers and print queues advertised by
the DNS-SD protocol.
https://bugzilla.gnome.org/show_bug.cgi?id=688956
You have attained a goal others have striven for. :)
https://lists.debian.org/debian-user/2017/09/msg00980.html
> > > > First things first. Are you still experiencing this behaviour on an
> > > > up-to-date unstable/testing system?
> > >
> > > Yes. I see this behaviour on stretch and sid.
> >
> > I am working with sid. Are you using AppArmor on Stretch?
>
> I have never explicitly enabled AppArmor. The stretch system is pretty
> close to a standard installation. I haven't fiddled with it much.
stretch....
> The sid system certainly isn't using AppArmor and could have a few
> oddities: It was installed as potato and upgraded since.
> > Let's see whether cups-browsed has any connection with the issue. Stop
> > it running and bring up evince. Its print dialog should show the remote
> > printers it gets from mdns broadcasts. You relate the printers disappear
> > a few times a day, so we shouldn't have to wait too long to see whether
> > it happens in this situation. BTW, is there any discernable pattern to
> > the behaviour? Time of day, time interval etc?
>
> As soon as I stop cups-browsed, all printers disappear. The ppd files
> are deleted. lpstat does not know them anymore and they disappear from
> the evince print dialog (or don't show up there if I restart evince).
> When cups-browsed is started again, the printers in evince, the ppd
> files and the lpstat output is back again pretty much immediately.
>
> Concerning the timing, I looked hard before filing the bug report. Log
> rotation was something obvious to correlate it to, but without luck. The
> waiting time seems exponentially distributed to me. Sometimes I had it
> multiple times within an hour other times a day went by without.
> When I ran the whole thing under strace, it didn't happen within 12h.
>
> > Thanks for the offer. Have a good look at what journalctl says. Search
> > for clues with "avahi", "audit", SIGTERM (and anything else you can
> > think of).
>
> I checked that much before the filing. I'm afraid we'll need to turn on
> some more logging to get useful things here. Just what should I enable?
> The manual page of avahi-daemon.conf is pretty scarce on debugging
> options. cups-browsed logging is pretty much off by default and when you
> enable it you only see the fact that printers get removed, not why.
> You see, this issue is not easy to debug. I hope you can bear with me.
knowledge of avahi is not great. It seems avahi-daemon stops providing
cups-browsed with information and the printer list would disappear, of
course. I would have been interesting to find out if the same thing
happens with the GTK dialog.
Cheers,
Brian.
>
> Helmut
Brian Potkin
Aug 15, 2022, 10:10:03 AM8/15/22
to
affects 846381 - cuos-daemon
thanks
On Tue 02 Jan 2018 at 17:51:06 +0000, Brian Potkin wrote:
[...]
> My interest in this bug arises from its affecting cups-daemon and my
> knowledge of avahi is not great. It seems avahi-daemon stops providing
> cups-browsed with information and the printer list would disappear, of
> course. I would have been interesting to find out if the same thing
> happens with the GTK dialog.
I am using cups 2.4.2-1+b1 on unstable with a default avahi-daemon.conf
and do not observe what you describe in your first post. cups always
sees the printers with 'lpstat -l -e'.
Cheers,
Brian.
thanks
On Tue 02 Jan 2018 at 17:51:06 +0000, Brian Potkin wrote:
[...]
> My interest in this bug arises from its affecting cups-daemon and my
> knowledge of avahi is not great. It seems avahi-daemon stops providing
> cups-browsed with information and the printer list would disappear, of
> course. I would have been interesting to find out if the same thing
> happens with the GTK dialog.
and do not observe what you describe in your first post. cups always
sees the printers with 'lpstat -l -e'.
Cheers,
Brian.
0 new messages