TL;DR: chronyd doesn't like server specifications with FQDN when there is no
DNS resolver available -- and neither does rival ntpd. We'll see if NXDOMAIN
is just as bad.
(I did check to see if this had already been reported -- didn't find any
reference to issues like I experienced. Went back two years.)
My story:
I live in a hilly area that experiences power dropouts of about 1.5 seconds
(more than a sag) during high winds. Tonight, I had four such events. My
edge router rebooted each time.
My edge router (CentOS 7 on four-port box) is connected via ARRIS BGW210-700
broadband gateway to AT&T UVerse fiber (100/20). As I am building this new
edge router, I hadn't gotten A Round Tuit to set up caching DNS yet.
Translation: using 8.8.8.8 and 8.8.4.4 only. I have a Time Machines
GPS-based source indicated by IP address (10.1.1.15); the rest of the sources
are downstream, called out with FQDNs.
After one of the power cycles, I checked matters with chronyc(1) and found
the only active NTP server in the "sources" list was my local GPS NTP box.
Everything else was missing. When I restarted chronyd, everything was there
as expected.
Fortunately, I'm qualifying the circuit and new edge router, so nothing is
live on it.
It would appear that not having DNS service available is fatal to bringing up
a server. So I have installed the caching DNS server so chrony will get
*something* as a response; we'll see on the next power fail if things look
better, or if NXDOMAIN results in the same.
By the way, I have another edge server running ntpd which *is* live, and it
behaves the same way...so both NTP daemons have the same, er, difficulty.
Now some of you will be saying "where's your UPS"? Another missing Round
Tuit -- the box is in the garage waiting to be opened and tested before I
tear my rack apart.
N.B.: the constant power cycling took out my LED desk lamp...
RFC: should I consider writing a script that will call chronyc to create the
servers again, say once a day?
1. Is this recommended?
2. Would this tend to eventually add all the servers
in [0123].centos.pool.ntp.org
3. Is there a better way to "wake up" servers rejected
because of no resolver, or NXDOMAIN if that causes drops?
4. If not, may I make a feature request?
--
To unsubscribe email chrony-users-request@xxxxxxxxxxxxxxxxxxxx with
"unsubscribe" in the subject.
For help email chrony-users-request@xxxxxxxxxxxxxxxxxxxx with "help" in the
subject.
Trouble? Email listmaster@xxxxxxxxxxxxxxxxxxxx.