NTP clock synchronization
For the master and tablet server daemons, the server’s clock must be synchronized
using Network Time Protocol (NTP). In addition, the maximum clock
error (not to be mistaken with the estimated error) must be below
a configurable threshold. The default value is 10 seconds, but it can be set with
the flag --max_clock_sync_error_usec.
If NTP is not installed, or if the clock is reported as unsynchronized, Kudu will not start, and will display a message such as:
F0924 20:24:36.336809 14550 hybrid_clock.cc:191 Couldn't get the current time: Clock unsynchronized. Status: Service unavailable: Error reading clock. Clock considered unsynchronized.
If NTP is installed and synchronized, but the maximum clock error is too high, you will see a message such as:
Sep 17, 8:13:09.873 PM FATAL hybrid_clock.cc:196 Couldn't get the current time: Clock synchronized, but error: 11130000, is past the maximum allowable error: 10000000
or
Sep 17, 8:32:31.135 PM FATAL tablet_server_main.cc:38 Check failed: _s.ok() Bad status: Service unavailable: Cannot initialize clock: Cannot initialize HybridClock. Clock synchronized but error was too high (11711000 us).
