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CentOS 6 NTP Server

It is important for systems administrators to make sure that mission-critical servers are always using the correct system time.

The ntpd (Network Time Protocol daemon) program is an operating system daemon which sets and maintains the system time of day in synchronism with Internet standard time servers. Make sure that the time zone configuration of your computer is correct. ntpd itself does not do anything about the time zones, it just uses UTC internally.

Install Network Time Protocol (NTP) daemon

# yum install ntp

Add NTP daemon to startup

# chkconfig ntpd on

Edit the NTPD config file

Here you can either use the default NTP public servers or add servers closer to your region.

Visit http://www.pool.ntp.org/en/ and either considder joining or getting your regional NTP pool servers

# vi /etc/ntp.conf
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
server 0.centos.pool.ntp.org
server 1.centos.pool.ntp.org
server 2.centos.pool.ntp.org

Start the NTP daemon

# service ntpd start

Standard NTP query program (ntpq)

Print a list of the peers known to the server as well as a summary of their state.

# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*javanese.kjsl.c 69.36.224.15     2 u  108  128  377    1.401    3.392   4.779
+66-191-139-149. 132.163.4.101    2 u   70  128  377   46.044   11.205   5.378
+ntp.sunflower.c 132.236.56.250   3 u   85  128  377   50.962   -2.129  14.112

Managing NTPd with Puppet

If you’re running Puppet we have included the manifest for installing Varnish on CentOS 6. If you’re not running Puppet then you can install it by following the instructions outlined in our CentOS 6 Puppet Install.

This is only the manifest and doesn’t include any of the files (i.e. ntp.conf).

class ntpd::install {
 
	$packagelist = ["ntp"]
 
	package { $packagelist:
		ensure => installed
	}
}
 
class ntpd::service {
 
	service { "ntpd":
		ensure => true,
		enable => true,
		hasrestart => true,
		hasstatus => true,
		require => Class ["ntpd::install"]
	}
}
 
class ntpd::conf {
 
	File {
		require => Class ["ntpd::install"],
		owner => "root",
		group => "root",
		mode => 644,
		notify => Class ["ntpd::service"]
	}
 
	file { "/etc/ntp.conf":
		source  => "puppet:///modules/ntpd/ntp.conf"
	}
}
 
class ntpd {
	include ntpd::install, ntpd::service, ntpd::conf
}

By George

Technical Samurai specializing in open source IT Automation and Cloud Infrastructure.