Do you know why uptime -s increasing in Azure platform?
hostname@ubuntu:~$ date Thu Jan 4 15:00:04 CET 2018 hostname@ubuntu:~$ uptime -s 2018-01-01 00:52:15
After 10 minutes:
hostname@ubuntu:~$ date Thu Jan 4 15:10:18 CET 2018 hostname@ubuntu:~$ uptime -s 2018-01-01 00:52:24
hostname@ubuntu:~$ ps -Afl
F S UID PID PPID C PRI NI ADDR SZ WCHAN STIME TTY TIME CMD
4 S root 1 0 0 80 0 – 30225 – Jan01 ? 00:00:49 /sbin/init
This host works stable
The apparent time that your system was booted, as shown by
uptime -s, changed because the system clock changed.
Let us look at the source code for
uptime, to see how it works.
/* Get the current time and convert it to a double */ gettimeofday(&tim, NULL); now = tim.tv_sec + (tim.tv_usec / 1000000.0);
We see here that it first gets the current time of day.
/* Get the uptime and calculate when that was */ uptime(&uptime_secs, &idle_secs); up_since_secs = (time_t) ((now - uptime_secs) + 0.5);
Next, it gets the actual uptime in seconds as reported by the kernel, and which would otherwise have been reported if you hadn’t used
-s. It then subtracts that number of seconds from the current time, rounding to the nearest second.
Thus, if the system clock is adjusted, the output of
-s will have a corresponding change.
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