NTP
From TBwiki
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| − | == Installing NTP<br> == | + | == Installing NTP<br> == |
<pre>yum install ntpd | <pre>yum install ntpd | ||
| − | </pre> | + | </pre> |
| − | == Configuring NTP == | + | == Configuring NTP == |
| − | === Setting the time zone<br> === | + | === Setting the time zone<br> === |
| − | Make sure that the host time zone is set properly. To modify the time zone go [http://kezhong.wordpress.com/2010/03/08/change-timezone-on-centos-5-4/ here]<br> | + | Make sure that the host time zone is set properly. To modify the time zone go [http://kezhong.wordpress.com/2010/03/08/change-timezone-on-centos-5-4/ here]<br> |
| − | === Setting the DNS server<br> === | + | === Setting the DNS server<br> === |
| − | Make sure your nameserver (DNS) is configured correctly (see [[TBLinux: | + | Make sure your nameserver (DNS) is configured correctly (see [[TBLinux:How to change the ip address|Modify the dhcp client configuration]]).<br> |
| − | === Modify NTP Server List<br> === | + | === Modify NTP Server List (Optional)<br> === |
| − | Modify your ntp server list | + | Modify your ntp server list |
| − | <pre>vim /etc/ntp.conf</pre> | + | <pre>vim /etc/ntp.conf</pre> |
| − | Change the server list for those closer to your server. List can be found [http://www.pool.ntp.org/en/ here]<br>Example for Canadian servers: <br> | + | Change the server list for those closer to your server. List can be found [http://www.pool.ntp.org/en/ here]<br>Example for Canadian servers: <br> |
<pre>server 0.ca.pool.ntp.org | <pre>server 0.ca.pool.ntp.org | ||
server 1.ca.pool.ntp.org | server 1.ca.pool.ntp.org | ||
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server 3.ca.pool.ntp.org | server 3.ca.pool.ntp.org | ||
| − | </pre> | + | </pre> |
| − | === Synchronize the host date with the NTP server<br> === | + | === Synchronize the host date with the NTP server<br> === |
| − | '''Warning''': This may result is a jump in time of several minutes.<br> | + | '''Warning''': This may result is a jump in time of several minutes.<br> |
| − | Use ntpdate to synchronize your server time with a NTP server.<br> | + | Use ntpdate to synchronize your server time with a NTP server.<br> |
| − | Example showing a host synchronization with a Canadian server.<br> | + | Example showing a host synchronization with a Canadian server.<br> |
<pre>ntpdate 0.ca.pool.ntp.org | <pre>ntpdate 0.ca.pool.ntp.org | ||
| − | </pre> | + | </pre> |
| − | === Start NTP<br> === | + | === Start NTP<br> === |
You can use the following command to enable NTP:<br> | You can use the following command to enable NTP:<br> | ||
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</pre> | </pre> | ||
| − | == Verify NTP server status<br> == | + | == Verify NTP server status<br> == |
| − | To | + | To verify the synchronization between the host and the NTP servers: |
<pre>ntpq -p</pre> | <pre>ntpq -p</pre> | ||
| − | <br>Example of host synched with barricade.rack9: <br> | + | '''Note''': After starting the NTP service, the system requires at least 10 minutes to accept a reference server. |
| + | |||
| + | <br>Example of host synched with barricade.rack9: <br> | ||
<pre> remote refid st t when poll reach delay offset jitter | <pre> remote refid st t when poll reach delay offset jitter | ||
============================================================================== | ============================================================================== | ||
Revision as of 16:58, 11 February 2011
Contents |
Installing NTP
yum install ntpd
Configuring NTP
Setting the time zone
Make sure that the host time zone is set properly. To modify the time zone go here
Setting the DNS server
Make sure your nameserver (DNS) is configured correctly (see Modify the dhcp client configuration).
Modify NTP Server List (Optional)
Modify your ntp server list
vim /etc/ntp.conf
Change the server list for those closer to your server. List can be found here
Example for Canadian servers:
server 0.ca.pool.ntp.org server 1.ca.pool.ntp.org server 2.ca.pool.ntp.org server 3.ca.pool.ntp.org
Synchronize the host date with the NTP server
Warning: This may result is a jump in time of several minutes.
Use ntpdate to synchronize your server time with a NTP server.
Example showing a host synchronization with a Canadian server.
ntpdate 0.ca.pool.ntp.org
Start NTP
You can use the following command to enable NTP:
chkconfig ntpd on service ntpd start
Verify NTP server status
To verify the synchronization between the host and the NTP servers:
ntpq -p
Note: After starting the NTP service, the system requires at least 10 minutes to accept a reference server.
Example of host synched with barricade.rack9:
remote refid st t when poll reach delay offset jitter ============================================================================== *barricade.rack9 209.51.161.238 2 u 1001 1024 377 31.147 -0.369 20.074 +ip-72-167-42-82 204.123.2.5 2 u 754 1024 377 166.388 -29.692 28.223 +cheezum.mattnor 129.7.1.66 2 u 91 1024 377 45.715 1.504 47.753
The '*' represent the current reference server
The '+' represent a potential backup reference server
The '-' represent a rejected reference server
