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Why NTP/ time is important in openstack

asked 2017-05-31 08:42:33 -0600

Prithvipal Singh gravatar image


I am learning openstack. I am following below link to install openstack. (

I got some questions while configuring NTP in environment section. 1. Why NTP is important in openstack? 2. Why all nodes must have same time? 3. What will happen if all nodes have different time?

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answered 2017-06-01 13:58:46 -0600

dsneddon gravatar image

NTP is always recommended, but only really required when you are running HA between your controller nodes. In that case, the clocks have to be very closely synchronized in order to manage the cluster and fail over properly.

In a non-HA environment, NTP will synchronize the clocks in order to make log correlation possible, and will ensure that the clocks never get out of sync far enough that authentication tokens appear to be expired. If that happens, you will lose the connections to all the APIs between two out-of-sync nodes.

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answered 2017-05-31 17:20:20 -0600

updated 2017-05-31 18:46:24 -0600

It's a requirement for the message queues used for communication between OpenStack components. If time isn't accurately synchronized, messages are not answered and communication is impossible.

In principle, NTP is not required. All you need is a method to keep the clocks in synch.

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answered 2017-06-01 04:41:26 -0600

abhijitsinha gravatar image

I agree with Bernd. Keeping the clocks in sync is the main purpose and NTP is a way to do that. If you are using storage services like Ceph, then time synchronisation is very critical.

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Asked: 2017-05-31 08:40:45 -0600

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Last updated: Jun 01 '17