| [chrony-users] reachability cycling between 377 to 000 |
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All: If I monitor the output from 'chronyc sources', I see the reachability status change regularly from "377" to "000" and back again. Is this a known problem or a wrong / incomplete configuration? After starting 'chronyd', the reachablilty goes from 0 to 377 as expected. 12 minutes (+/-1 poll interval) after "377", reachability starts dropping every 16 s poll interval (376, 374, 370, ...) down to 000. There it stays for 12 minutes, at which point reachability starts ascending (000, 003, 007, ...) back to 377. The process then repeats. Typical data from ‘chronyc -s’ is shown below. I'm using a Raspberry Pi 4B and Uputronics GPS HAT (uBlox 8) with 'gpsd' (versions shown below). I built it following the instructions on the NTPSEC documentation page, “Stratum-1-Microserver HOWTO”. This includes stripping non-essential (for NTPSEC) services. Details, including ‘ps’ output for ‘chronyd’ and ‘gpsd’ are below. 'cgps -s' shows nothing obviously wrong to my eye. I have a cheapo puck antenna in the window with mostly south exposure. Capturing NMEA GGA sentences as close as possible to the reachability changes always shows a lock at that time (field 5, "FS Fix Status). This setup runs 'ntpsec' as expected, with perhaps a little more jitter than I'd like. There is no change in reachability once 377 is achieved at startup. Thanks for any ideas for fixing or further troubleshooting. -wis Test Setup RPI 4B with 2GB RAM and latest firmware, Uputronics GPS HAT (uBlox 8) ----------------------- wis@raspberrypi:~ $ cat /proc/cpuinfo | perl -ane 'next if( ! /(Revision|Hardware)/m); print' Hardware : BCM2711 Revision : b03111 wis@raspberrypi:~ $ uname -a Linux raspberrypi 5.4.51-v7l+ #1333 SMP Mon Aug 10 16:51:40 BST 2020 armv7l GNU/Linux wis@raspberrypi:~ $ chronyd -v chronyd (chrony) version 3.5.1 (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP -SCFILTER -SIGND +ASYNCDNS -SECHASH +IPV6 -DEBUG) wis@raspberrypi:~ $ gpsd -V gpsd: 3.21.1~dev (revision release-3.21-191-ge80e4bd75) wis@raspberrypi:~ $ sudo rpi-eeprom-update BCM2711 detected Dedicated VL805 EEPROM detected BOOTLOADER: up-to-date CURRENT: Thu 03 Sep 2020 12:11:43 PM UTC (1599135103) LATEST: Thu 03 Sep 2020 12:11:43 PM UTC (1599135103) FW DIR: /lib/firmware/raspberrypi/bootloader/critical VL805: up-to-date CURRENT: 000138a1 LATEST: 000138a1 wis@raspberrypi:~ $ ps -aux | grep sbin/gpsd | grep -v grep nobody 426 0.1 0.0 11776 1664 ? S<sl Oct10 7:56 /usr/local/sbin/gpsd -P /var/run/gpsd.pid /dev/gpsd0 wis@raspberrypi:~ $ ps -aux | grep sbin/chronyd | grep -v grep root 19180 0.8 0.0 12396 1864 ? S 09:12 4:10 /usr/local/sbin/chronyd wis@raspberrypi:~ $ gpsd/ubxtool -p MON-VER -P 18.00 ubxtool: poll MON-VER sent: UBX-MON-VER: Poll request ... UBX-MON-VER: swVersion ROM CORE 3.01 (107888) hwVersion 00080000 extension FWVER=SPG 3.01 extension PROTVER=18.00 extension GPS;GLO;GAL;BDS extension SBAS;IMES;QZSS ... ----------------------- data ( "chronyc -s | grep PPS", captured when reachability changes, followed by "gpspipe -r -t -n 13 | grep GGA", both within a perl script with some line editing for clarity and calculating the delta T between changes in the last column. The next to last column is the "fix" status in the GGA NMEA sentence, 1: GPS fix, 2: DGPS fix ). wis@raspberrypi:~ $ tail -50 chrony_mon 2020-10-15T15:00:21 #* PPS 0 4 200 124 -231 ns[ -364 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:00:37 #* PPS 0 4 0 139 -231 ns[ -364 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:12:21 #* PPS 0 4 1 4 +30 ns[ +8058 ns] +/- 444 ns GGA lock: 2 11:44 2020-10-15T15:12:37 #* PPS 0 4 3 8 -14 ns[ -25 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:12:53 #* PPS 0 4 7 8 +147 ns[ +234 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:13:09 #* PPS 0 4 17 7 -48 ns[ -65 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:13:25 #* PPS 0 4 37 7 +272 ns[ +346 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:13:41 #* PPS 0 4 77 8 -216 ns[ -264 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:13:57 #* PPS 0 4 177 9 +2 ns[ +2 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:14:13 #* PPS 0 4 377 7 +462 ns[ +539 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:26:29 #* PPS 0 4 376 28 -584 ns[ -672 ns] +/- 444 ns GGA lock: 2 12:16 2020-10-15T15:26:45 #* PPS 0 4 374 44 -584 ns[ -672 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:27:01 #* PPS 0 4 370 60 -584 ns[ -672 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:27:17 #* PPS 0 4 360 76 -584 ns[ -672 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:27:33 #* PPS 0 4 340 92 -584 ns[ -672 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:27:49 #* PPS 0 4 300 108 -584 ns[ -672 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:28:05 #* PPS 0 4 200 124 -584 ns[ -672 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:28:21 #* PPS 0 4 0 140 -584 ns[ -672 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:40:21 #* PPS 0 4 1 11 -37 ns[ -7074 ns] +/- 444 ns GGA lock: 2 12:00 2020-10-15T15:40:37 #* PPS 0 4 3 7 -5 ns[ -88 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:40:53 #* PPS 0 4 7 7 -382 ns[ -594 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:41:09 #* PPS 0 4 17 6 +105 ns[ +141 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:41:25 #* PPS 0 4 37 8 -177 ns[ -225 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:41:41 #* PPS 0 4 77 7 -110 ns[ -134 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:41:57 #* PPS 0 4 177 6 -307 ns[ -365 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:42:13 #* PPS 0 4 377 7 -167 ns[ -194 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T15:54:13 #* PPS 0 4 376 29 -83 ns[ -115 ns] +/- 543 ns GGA lock: 2 12:00 2020-10-15T15:54:29 #* PPS 0 4 374 45 -83 ns[ -115 ns] +/- 543 ns GGA lock: 2 00:16 2020-10-15T15:54:45 #* PPS 0 4 370 61 -83 ns[ -115 ns] +/- 543 ns GGA lock: 2 00:16 2020-10-15T15:55:01 #* PPS 0 4 360 77 -83 ns[ -115 ns] +/- 543 ns GGA lock: 2 00:16 2020-10-15T15:55:17 #* PPS 0 4 340 93 -83 ns[ -115 ns] +/- 543 ns GGA lock: 2 00:16 2020-10-15T15:55:33 #* PPS 0 4 300 109 -83 ns[ -115 ns] +/- 543 ns GGA lock: 2 00:16 2020-10-15T15:55:49 #* PPS 0 4 200 125 -83 ns[ -115 ns] +/- 543 ns GGA lock: 2 00:16 2020-10-15T15:56:05 #* PPS 0 4 0 141 -83 ns[ -115 ns] +/- 543 ns GGA lock: 2 00:16 2020-10-15T16:07:49 #* PPS 0 4 1 9 -57 ns[ -1228 ns] +/- 444 ns GGA lock: 2 11:44 2020-10-15T16:08:05 #* PPS 0 4 3 7 -26 ns[ -73 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:08:21 #* PPS 0 4 7 9 -98 ns[ -149 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:08:37 #* PPS 0 4 17 8 -13 ns[ -33 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:08:53 #* PPS 0 4 37 8 -336 ns[ -428 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:09:09 #* PPS 0 4 77 7 +499 ns[ +610 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:09:25 #* PPS 0 4 177 9 +41 ns[ +50 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:09:41 #* PPS 0 4 377 8 -50 ns[ -58 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:21:41 #* PPS 0 4 376 28 -400 ns[ -522 ns] +/- 444 ns GGA lock: 2 12:00 2020-10-15T16:21:57 #* PPS 0 4 374 44 -400 ns[ -522 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:22:13 #* PPS 0 4 370 60 -400 ns[ -522 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:22:29 #* PPS 0 4 360 76 -400 ns[ -522 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:22:45 #* PPS 0 4 340 92 -400 ns[ -522 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:23:01 #* PPS 0 4 300 108 -400 ns[ -522 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:23:17 #* PPS 0 4 200 124 -400 ns[ -522 ns] +/- 444 ns GGA lock: 2 00:16 2020-10-15T16:23:33 #* PPS 0 4 0 140 -400 ns[ -522 ns] +/- 444 ns GGA lock: 2 00:16 ‘cgps -s’ output ┌───────────────────────────────────────────┐┌──────────────────Seen 24/Used 11┐ │ Time: 2020-10-16T00:45:08.000Z (18)││ PRN Elev Azim SNR Use │ │ Latitude: <masked> N ││GP 3 64.0 177.0 25.0 Y │ │ Longitude: <masked> W ││GP 4 71.0 325.0 33.0 Y │ │ Alt (HAE, MSL): 406.827, 482.211 ft ││GP 6 21.0 301.0 31.0 Y │ │ Speed: 0.01 mph ││GP 7 13.0 231.0 29.0 Y │ │ Track (true, var): 12.3, 14.7 deg ││GP 9 35.0 290.0 28.0 Y │ │ Climb: 0.00 ft/min ││GP 16 37.0 125.0 37.0 Y │ │ Status: 3D DGPS FIX (2 secs) ││GP 22 42.0 166.0 29.0 Y │ │ Long Err (XDOP, EPX): 0.51, +/- 6.4 ft ││GP 26 39.0 75.0 30.0 Y │ │ Lat Err (YDOP, EPY): 0.65, +/- 8.7 ft ││GP 31 14.0 52.0 21.0 Y │ │ Alt Err (VDOP, EPV): 1.41, +/- 21.9 ft ││GL 71 44.0 110.0 21.0 Y │ │ 2D Err (HDOP, CEP): 0.88, +/- 13.4 ft ││GL 73 43.0 41.0 13.0 Y │ │ 3D Err (PDOP, SEP): 1.66, +/- 138 ft ││GP 1 2.0 198.0 0.0 N │ │ Time Err (TDOP): 0.87 ││GP 2 1.0 338.0 0.0 N │ │ Geo Err (GDOP): 1.88 ││SB 46 39.0 189.0 0.0 N │ │ ECEF X, VX: -2505536.420 m 0.010 m/s ││SB 48 38.0 194.0 0.0 N │ │ ECEF Y, VY: -3848833.310 m -0.020 m/s ││SB 51 37.0 158.0 0.0 N │ │ ECEF Z, VZ: 4411330.600 m 0.000 m/s ││GL 65 31.0 317.0 0.0 N │ │ Speed Err (EPS): +/- 1.0 mph ││GL 72 71.0 n/a 0.0 N │ │ Track Err (EPD): +/- 193 deg ││GL 74 73.0 155.0 0.0 N │ │ Time offset: 0.471591566 s ││GL 75 19.0 199.0 0.0 N │ │ Grid Square: <masked> ││GL 81 8.0 345.0 0.0 N │ └───────────────────────────────────────────┘└More...──────────────────────────┘ |
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