You can easily install NTP (Network Time Protocol, a means of transmitting time signals over a computer network) using the yum command under Red Hat or CentOS/Fedora Linux server or workstation based systems. You need to install the following packages:
| Tutorial details | |
|---|---|
| Difficulty level | Easy |
| Root privileges | Yes |
| Requirements | NTPD server |
| Est. reading time | 5m |
- ntp : ntpd server which continuously adjusts system time and utilities used to query and configure the ntpd daemon.
- ntpdate : Utility to set the date and time via NTP.
- ntp-doc : NTP documentation
Procedure: Setup NTPD on CentOS Linux
Open the terminal or login over the ssh session. You must login as as the root user. Type the following yum command to install ntp
# yum install ntp ntpdate ntp-doc
Turn on service, enter:
# chkconfig ntpd on
Synchronize the system clock with 0.pool.ntp.org server (use this command only once or as required):
# ntpdate pool.ntp.org
Start the NTP server. The following will continuously adjusts system time from upstream NTP server. No need to run ntpdate:
# /etc/init.d/ntpd start
Configure ntpd (optional)
Edit /etc/ntp.conf, enter:
# vi /etc/ntp.conf
Set public servers from the pool.ntp.org project:
server 0.rhel.pool.ntp.org server 1.rhel.pool.ntp.org server 2.rhel.pool.ntp.org
See this tutorial on how to configure NTPD for LAN based client on RHEL / CentOS Linux for more information.
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Nice inof, but how do i configure a NTP server? i want to do this with a client and a server… Thanks
Thanks, very straight forward.
This helped me to fix my call of duty world at war server problem.
Thank you.
Does anyone know how to make it run ntpdate at certain time increments?
Like every hour?
Thanks
Setup a cronjob.
Good info, very helpful.
Thanks!
Thanks, very simple to install and configure. My time is synchronized now.
nice information but please tell me about the client end that how i sync time server with clients
See: CentOS / Red Hat Configure an NTP Client And Server
thanks man
very nice
is there a way where i can use my own server from which clients should sync time?
I did ntpdate 0.asia.pool.ntp.org
and now all my servers showing different time. Any idea why
server1 – Wed Jan 6 15:54:10 IST 2010
server2 – Wed Jan 6 15:47:39 IST 2010
server3 – Wed Jan 6 15:58:23 IST 2010
For more infomation – My servers are in India
Thanks in advance
@Kunal,
My guess: You are obtaining your time info from a pool, so each time you synchronize you’re really getting your time form a different server. This shouldn’t matter, but it seems that the different servers in that pool are not synchronized with each other. You could pick a single server out of the pool and synchronize with it directly on each of your servers.
Or, even better, set up your own ntp server, have it synchronize with a quality outside time server, then have the rest of your servers sync up with the time server that you installed. That way, even if there’s an accuracy problem upstream, at least all of your servers will agree with each other.
I have this error:
ntpdate[14060]: step-systime: Operation not permitted
This is likely related to the server being a virtual server. It is not possible to sync to ntp in a VPS because the clock is inherited from the hardware that you are hosted on.
I just ran across the same problem.
Very useful
Very Helpful :)
Replying @Anonymous June 4, 2010
Actually if you mean a Xen VM, you still can have your own independent system clock setting the following sysctl parameter.
sysctl -w xen.independent_wallclock = 1;
And you save it inside /etc/sysctl.conf
Thanks for this tip!
Thanks you for your instructions.
This is exactly what I was looking for. Thank you for this clear post. :)
Thank you this was very helpful!
i have configured ntp server on my machine which runs rhel6
but at the client side at the time of ntp setting it giving me error tha
server is note reachable or doesn’t act as a ntp server and also i cant
see the port of ntp is open on my system, will you please help me for this
Thanks
Thanks but setting up / configuriing ntp servers list would be useful also
Thank you very much, it was exactly as you said.
Thanks a lot. great howto…
i am from Malaysia. which server should i use ?
Great post ,, and it works as a charm :) ,, thank you very much
Thanks a lot for your concise post.
The following command will additionally update your hardware clock
hwclock –systohc
Very helpful. Thanks
You dont need to have an ntp server running in your machine in order to have the time synced, it is as easy as having cron do the syncing with the ‘ntpclient’ command.
Hi Fred,
Could you please share script to sync with ntp server. so that i can run the same as a cron job.
Thank you much.
Thanks!!!
Thanks! you saved my day!
Thank you very much ! Very useful guide.
Hi,
I’m having a small issue on Fedora 21: when my computer goes to sleep, I lose time synchronization and have to manually restart ntpd when I wake it in order to resync. Any idea how to fix this?
Great tutorial! Thanks so much from Brazil.
Ed
Thanks! Very helpful.