Synchronizing cluster node clocks
It is important to ensure all cluster node’s clocks are synchronized using Chrony and/or NTP. Without this synchronization, there may be problems with internal cluster communications and have downstream impacts.
When you initially install Redis Enterprise Software, the install script asks for permission to configure a scheduled Cron job if it does not detect Chrony or NTP. This should ensure the node’s clock is always synchronized. If you did not confirm configuring this job during the installation process, you must use the Network Time Protocol (NTP) regularly to ensure that all server clocks are synchronized.
To synchronize the server clock, run the command relevant to your host’s operating system. For example, in Ubuntu, the following command can be used to synchronize a server’s clock to an NTP server:
$ sudo /etc/network/if-up.d/ntpdate
If you are using Geo-Replication, it is critical to keep OS clocks consistent across clusters as well. Certain aspects of conflict resolution are achieved using OS time. For specific information, please see Network Time Services as they pertain to CRDBs.