ProCKSI

h1. Time Synchronisation

The system time on all nodes must be synchronized as 

 a) data is written/read on/from a common, shared file system or even expires after a certain period of time and must be deleted, and 

 b) system logs are maintained independently but entries must be able to be associated with each other.

* Add your own time server to _/etc/ntp/ntpservers_: 

<pre>

   128.243.21.16 #marian.cs.nott.ac.uk

   128.243.21.17 #robin.cs.nott.ac.uk

   128.243.21.18 #tuck.cs.nott.ac.uk

   128.243.21.19 #pat.cs.nott.ac.uk

</pre>

* Modify _/etc/ntp.conf_ in order to permit systems on the subnet to synchronise with this time service:

<pre>

   # -- CLIENT NETWORK -------

   restrict 192.168.199.0 mask 255.255.255.0 nomodify notrap

   broadcastclient

</pre>

* Modify _/etc/ntp.conf_ and add further time servers:

<pre>

   # --- OUR TIMESERVERS -----

   server 128.243.21.16 #marian.cs.nott.ac.uk

   restrict 128.243.21.16 mask 255.255.255.255 nomodify notrap noquery

   server 128.243.21.17 #robin.cs.nott.ac.uk

   restrict 128.243.21.17 mask 255.255.255.255 nomodify notrap noquery

   server 128.243.21.18 #tuck.cs.nott.ac.uk

   restrict 128.243.21.18 mask 255.255.255.255 nomodify notrap noquery

   server 128.243.21.19 #pat.cs.nott.ac.uk

   restrict 128.243.21.19 mask 255.255.255.255 nomodify notrap noquery

</pre>

* Make the NTP daemon start at bootup. Enter at the command line of the master node and each slave node:

<pre>

   /sbin/chkconfig  --add ntpd

   /sbin/chkconfig  ntpd  on

</pre>

* Start the NTP daemon. Enter at the command line of the master node and each slave node:

<pre>

   /sbin/service ntpd start

</pre>