Configure the ntpd daemon to be started, at run time and to use the correct name servers.

Configure state

enable the ntp service to run at 3,4,5 runlevels

[Parameters]

ntp_server0 = ip-time-0.cern.ch

ntp_server1 = ip-time-1.cern.ch

ntp_server2 = ip-time-2.cern.ch

client_networks = undef

Modifying the ntp.conf

change the ntp server domains to ips with the gethostbyname() function ( /etc/ntp.conf understands both fqdn and IPs so we probably wont have any problem writing the fqdns )

• Remove lines, "restrict default nomodify notrap nopeer noquery","restrict 127.0.0.1","restrict ::1" and add "restrict default ignore", in order to remove restriction
• Remove all defined servers( e.g. in Centos server 0.centos.pool.ntp.org iburst ) and add our ntp servers e.g for ip-time-0.cern.ch, "server 137.138.18.69", "restrict 137.138.18.69 mask 255.255.255.255 nomodify notrap noquery"
• Remove fudge servers (e.g server "137.138.16.69 # added by /sbin/dhclient-script") and just add localhost in case of network outages, "fudge 127.127.1.0 stratum 10"
• allow some debugging via ntpdc, but with no modifications, "restrict 127.0.0.1 nomodify notrap"
• add our own clients in case we are a real "server", "server 127.0.0.1", "restrict <<IP>> mask <<MASK>> nomodify notrap"

$diff /etc/ntp.conf.old /etc/ntp.conf

8d7
< restrict default nomodify notrap nopeer noquery
13,14d11
< restrict 127.0.0.1
< restrict ::1
21,24d17
< server 0.centos.pool.ntp.org iburst
< server 1.centos.pool.ntp.org iburst
< server 2.centos.pool.ntp.org iburst
< server 3.centos.pool.ntp.org iburst
59,60c52,61
< server 137.138.16.69 # added by /sbin/dhclient-script
< server 137.138.17.69 # added by /sbin/dhclient-script
---
> # This file is under NCM-ntpd control.
> restrict default ignore
> server 137.138.18.69
> restrict 137.138.18.69 mask 255.255.255.255 nomodify notrap noquery
> server 137.138.16.69
> restrict 137.138.16.69 mask 255.255.255.255 nomodify notrap noquery
> server 137.138.17.69
> restrict 137.138.17.69 mask 255.255.255.255 nomodify notrap noquery
> fudge 127.127.1.0 stratum 10
> restrict 127.0.0.1 nomodify notrap

Modifying the /etc/ntp/step-tickers

Rewrite everything with the ntp servers IPs

e.g

$ cat /etc/ntp/step-tickers
137.138.18.69
137.138.16.69
137.138.17.69

Reload the ntp service if the files are changed.

Unconfigure State

Nothing done to unconfigure the ntp component.