kvm/internal/timesync/ntp.go

114 lines
2.8 KiB
Go

package timesync
import (
"math/rand/v2"
"strconv"
"time"
"github.com/beevik/ntp"
)
var defaultNTPServers = []string{
"time.apple.com",
"time.aws.com",
"time.windows.com",
"time.google.com",
"162.159.200.123", // time.cloudflare.com
"0.pool.ntp.org",
"1.pool.ntp.org",
"2.pool.ntp.org",
"3.pool.ntp.org",
}
func (t *TimeSync) queryNetworkTime() (now *time.Time, offset *time.Duration) {
chunkSize := 4
ntpServers := t.ntpServers
// shuffle the ntp servers to avoid always querying the same servers
rand.Shuffle(len(ntpServers), func(i, j int) { ntpServers[i], ntpServers[j] = ntpServers[j], ntpServers[i] })
for i := 0; i < len(ntpServers); i += chunkSize {
chunk := ntpServers[i:min(i+chunkSize, len(ntpServers))]
now, offset := t.queryMultipleNTP(chunk, timeSyncTimeout)
if now != nil {
return now, offset
}
}
return nil, nil
}
type ntpResult struct {
now *time.Time
offset *time.Duration
}
func (t *TimeSync) queryMultipleNTP(servers []string, timeout time.Duration) (now *time.Time, offset *time.Duration) {
results := make(chan *ntpResult, len(servers))
for _, server := range servers {
go func(server string) {
scopedLogger := t.l.With().
Str("server", server).
Logger()
// increase request count
metricNtpTotalRequestCount.Inc()
metricNtpRequestCount.WithLabelValues(server).Inc()
// query the server
now, response, err := queryNtpServer(server, timeout)
// set the last RTT
metricNtpServerLastRTT.WithLabelValues(
server,
).Set(float64(response.RTT.Milliseconds()))
// set the RTT histogram
metricNtpServerRttHistogram.WithLabelValues(
server,
).Observe(float64(response.RTT.Milliseconds()))
// set the server info
metricNtpServerInfo.WithLabelValues(
server,
response.ReferenceString(),
strconv.Itoa(int(response.Stratum)),
strconv.Itoa(int(response.Precision)),
).Set(1)
if err == nil {
// increase success count
metricNtpTotalSuccessCount.Inc()
metricNtpSuccessCount.WithLabelValues(server).Inc()
scopedLogger.Info().
Str("time", now.Format(time.RFC3339)).
Str("reference", response.ReferenceString()).
Str("rtt", response.RTT.String()).
Str("clockOffset", response.ClockOffset.String()).
Uint8("stratum", response.Stratum).
Msg("NTP server returned time")
results <- &ntpResult{
now: now,
offset: &response.ClockOffset,
}
} else {
scopedLogger.Warn().
Str("error", err.Error()).
Msg("failed to query NTP server")
}
}(server)
}
result := <-results
return result.now, result.offset
}
func queryNtpServer(server string, timeout time.Duration) (now *time.Time, response *ntp.Response, err error) {
resp, err := ntp.QueryWithOptions(server, ntp.QueryOptions{Timeout: timeout})
if err != nil {
return nil, nil, err
}
return &resp.Time, resp, nil
}