Wednesday, June 17, 2015

NTP leap second fix - Red Hat stuff

Resolve Leap Second Issues in Red Hat Enterprise Linux

Leap seconds are a periodic one-second adjustment of Coordinated Universal Time(UTC) in order to keep a system's time of day close to the mean solar time. However, the Earth's rotation speed varies in response to climatic and geological events, and due to this, UTC leap seconds are irregularly spaced and unpredictable. This article seeks to provide information regarding the leap seconds themselves, along with addressing how Red Hat Enterprise Linux handles the insertion of one.

The next leap second insertion is scheduled for June 30th, 2015 at 23:59:60 UTC.

Systems running any version of Red Hat Enterprise Linux should automatically account for leap second corrections if they are using the NTP (Network Time Protocol) daemon to synchronize their local timekeeping with an NTP server. During the last day before a leap second correction, NTP servers should notify their clients that a leap second will occur, and at 23:59:59 UTC, the Linux kernel should add or remove an extra second by making the 60th second occur twice or removing it entirely.