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Early warning about GPS week rollover

Apr 04, 2019 GMT+08:00

I. Summary

According to the official release of the US GPS, the older GPS devices are not protected against Week Number Rollover issue. This bug will reset clock to 1024 weeks ago when the UTC time on April 6, 2019, at 23:59:42 (Beijing time, April 7th, 7:59:42). If the top-level (stratum 1) clock source is adjusted, its associated sub-level node of NTP will also be adjusted, which will have a huge impact on the business of node that run NTP as client.

In fact, the current authoritative time service center can avoid the impact of this event, and the probability of failure is low, but we remain need caution.

II. Solution

In order to ensure the stable running of the customer's business, please refer to the following instructions and check your server.

1. If server configure ntp.myhuaweicloud.com (Huawei cloud internal NTP clock source and this is default configuration of Huawei cloud OS), it will not be affected by this event. 

2. If server configure a third-party NTP clock source, please consult with provider of third-party NTP server. Please refer to chapter 3 of guide for querying NTP cloud source of server.

3. If you are unable to contact third-party NTP server, or if you do not know the scope of the problem, we recommends that turning off the clock source for Linux host and adjusting registry parameters for Windows host. Please refer to chapter 4 of guide for operation.

4. If you do not perform any NTP related circumvention measures before the rollover time, you will find that the host NTP service dead or exit. Please do not restart the NTP service immediately, you can restart NTP service until upper NTP clock source has returned to normal.