Re: [chrony-users] Problem when removing all sources

[Thomas Lange <thomas@xxxxxxxxxxxx>]

On 2023-11-21 12:51, Miroslav Lichvar wrote:
> On Mon, Nov 20, 2023 at 04:17:47PM +0100, Miroslav Lichvar wrote:
> > On Mon, Nov 20, 2023 at 11:14:00AM +0100, Thomas Lange wrote:
> > > <chronyc reload sources>
> > >
> > > 2023-11-19T17:43:20Z Removed source 103.242.68.69
> > > 2023-11-19T17:43:20Z Removed source 162.159.200.123
> > > 2023-11-19T17:43:20Z Removed source 194.58.202.148
> > > 2023-11-19T17:43:20Z Selected source 194.58.206.20
> > > 2023-11-19T17:43:20Z Removed source 194.58.206.20
> > > 2023-11-19T17:43:20Z Removed source 217.75.106.216
> > > 2023-11-19T17:43:20Z Removed source 91.209.0.17
> > >
> > > <Missing "Can't synchronise: no selectable sources" >
> >
> > It depends on the order of removed sources and the reselection that
> > can happen.
> >
> > The message is logged only when a source is already selected and
> > newly executed source selection doesn't find a selectable source.
> > In your example the last selected source is 194.58.206.20. It is
> > removed, i.e. nothing is selected, and with the two remaining sources
> > there is no successful selection.
>
> The issue actually was in the removal of the source. If it was
> reselected due to becoming offline, the log message was logged. If it
> was kept selected even as offline (due to other sources not being
> better), it would not be logged.
>
> The latest development code now has a fix to make it consistent.

Thanks, I like consistency. I reran my tests using 4.5-pre1 and my test case
seems to work now. However, I found another test case that doesn't.

It's the same setup as in my original post but instead of removing all
sources and leaving chrony without any sources at all, I add an unreachable
server. This results in:

I don't get the "Can't synchronise: no selectable sources" log message.

'chronyc tracking' still reports the now removed server. Perhaps this
is expected.

Logs below.

/Thomas

# chronyd -d
2023-11-23T08:45:54Z chronyd version 4.5-pre1 starting (+CMDMON +NTP +REFCLOCK -RTC +PRIVDROP -SCFILTER -SIGND -ASYNCDNS -NTS -SECHASH -IPV6 +DEBUG)
2023-11-23T08:45:54Z Running with root privileges
2023-11-23T08:45:54Z Frequency 0.814 +/- 4.379 ppm read from /var/lib/chrony/drift
2023-11-23T08:45:54Z Added source 103.242.68.69
2023-11-23T08:45:54Z Added source 162.159.200.123
2023-11-23T08:45:54Z Added source 194.58.202.148
2023-11-23T08:45:54Z Added source 194.58.206.20
2023-11-23T08:45:54Z Added source 217.75.106.216
2023-11-23T08:45:54Z Added source 91.209.0.17
2023-11-23T08:46:00Z Selected source 91.209.0.17
2023-11-23T08:46:01Z Selected source 194.58.206.20
2023-11-23T08:46:27Z Removed source 103.242.68.69
2023-11-23T08:46:27Z Removed source 162.159.200.123
2023-11-23T08:46:27Z Removed source 194.58.202.148
2023-11-23T08:46:27Z Removed source 194.58.206.20
2023-11-23T08:46:27Z Removed source 217.75.106.216
2023-11-23T08:46:27Z Removed source 91.209.0.17
2023-11-23T08:46:27Z Added source 172.16.1.99

-----

# rm chrony.sources
# cp /tmp/new.sources .
# cat new.sources
server 172.16.1.99 burst iburst xleave
# chronyc reload sources
200 OK
# chronyc tracking
Reference ID    : C23ACE14 (194.58.206.20)
Stratum         : 2
Ref time (UTC)  : Thu Nov 23 08:45:59 2023
System time     : 0.000013376 seconds slow of NTP time
Last offset     : +0.003778137 seconds
RMS offset      : 0.003778137 seconds
Frequency       : 0.814 ppm fast
Residual freq   : +107.309 ppm
Skew            : 4.379 ppm
Root delay      : 0.032012437 seconds
Root dispersion : 0.006136328 seconds
Update interval : 0.8 seconds
Leap status     : Normal
# chronyc sources
MS Name/IP address         Stratum Poll Reach LastRx Last sample
===============================================================================
^? 172.16.1.99                   0   7     0     -     +0ns[   +0ns] +/-    0ns

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