Eu tenho a configuração do NTP para rodar com o GPSd e tudo está bem. O problema surge depois de cerca de uma semana do meu pi de framboesa sendo desconectado, o NTP irá confiar na data antiga no relógio do sistema. Como o GPS leva alguns segundos para obter energia e adquirir um bloqueio, parece que o NTP confiará no meu relógio local e nunca mais verificará o GPS novamente.
Curiosamente, se eu executar ntpq -p , vejo:
SHM(0) .GPS. 0 l - 16 0 0.000 0.000 0.000
*LOCAL(0) .LOCL. 10 l 45 64 377 0.000 0.000 0.001
Em seguida, execute exatamente o mesmo comando imediatamente após:
*SHM(0) .GPS. 0 l 1 16 0 0.000 9516243 0.001
LOCAL(0) .LOCL. 10 l 45 64 377 0.000 0.000 0.001
Por algum motivo, embora o GPS estivesse on-line e informando o tempo, o NTP nunca tentou pesquisá-lo novamente até que eu corresse ntpq -p
Minha configuração é a seguinte:
# WARNING: Disabling the panicgate is insecure when you don't fully trust your time calibrations. Since we are
# only using a GPS, this is okay.
tinker panic 0
# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
restrict default kod nomodify notrap nopeer
restrict -6 default kod nomodify notrap nopeer
# Permit all access over the loopback interface. This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1
restrict -6 ::1
# Only allow on our own network
restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
# Read the rough GPS time from device 127.127.28.0
# Read the accurate PPS time from device 127.127.28.1
# The flag1 will allow skipping the time difference, see driver28 in NTP documentation:
# https://www.eecis.udel.edu/~mills/ntp/html/drivers/driver28.html
server 127.127.28.0 minpoll 4 maxpoll 4 iburst prefer
fudge 127.127.28.0 time1 0.535 refid GPS flag1 1
# Local clock backup
server 127.127.1.0 # local clock
fudge 127.127.1.0 stratum 10
# Use servers from the ntp pool for the first synchronization,
# or as a backup if the GPS is disconnected
server 0.pool.ntp.org
server 1.pool.ntp.org
server 2.pool.ntp.org
server 3.pool.ntp.org
# Ignore all other interfaces but itself
interface ignore wildcard
interface listen 127.0.0.1
interface listen ::1
# Drift file. Put this in a directory which the daemon can write to.
# No symbolic links allowed, either, since the daemon updates the file
# by creating a temporary in the same directory and then rename()’ing
# it to the file.
driftfile /var/lib/ntp/drift
logfile /var/log/ntp.log
statsdir /var/log/ntp/
statistics loopstats peerstats clockstats
filegen loopstats file loopstats type day enable
filegen peerstats file peerstats type day enable
filegen clockstats file clockstats type day enable
Qualquer ajuda seria muito apreciada. Estou quase no ponto de ter um cronjob executando o comando de vez em quando, para que o GPS tenha uma chance de responder.