How To Synchronize Time Across a Linux Cluster

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Introduction

For proper cluster functionality, all nodes in the cluster need to have their clocks synchronized, even when the cluster is isolated from the Internet and global time sync servers. To accomplish this, we installed NTP on Ubuntu/Linux and configured one node to act as the main time server, while the other nodes act as clients to main time server. This how-to tutorial describes how to set up your machine as a local Network Time Protocol (NTP) server and how to use the NTP daemon to regularly maintain an accurate system time across the cluster. We hope you find the below information useful in building your own clusters.

Install NTP on all Nodes

On all nodes install NTP and set the timezone to UTC.

NTP Server

Choose one node as the main time server and set it up to run properly even if it is not connected to the Internet.

Add the following to provide your current local time as a default should you temporarily (or permanently) lose Internet connectivity:

Restart NTP:

NTP Clients

On all the remaining nodes in your cluster, set them up to sync clocks with the node which was designated as the main time server in the cluster.

Add:

, where <main time server> is the ip address of the node designated as the main time server.

Remove the following lines in the con file by commenting out with a # character at the beginning of the line:

Restart NTP:

Check Connectivity to main time server: