{"id":44,"date":"2009-05-04T22:06:33","date_gmt":"2009-05-04T20:06:33","guid":{"rendered":"http:\/\/46.105.150.90\/tstnunix\/?p=44"},"modified":"2009-05-04T22:06:33","modified_gmt":"2009-05-04T20:06:33","slug":"ntp-things","status":"publish","type":"post","link":"https:\/\/nunix.fr\/?p=44","title":{"rendered":"Ntp things : synchronize your date … with Xen"},"content":{"rendered":"

{jcomments on}To keep your system clock accurate, it exists the ntp protocol : \u00ab\u00a0NTP<\/a>\u00ab\u00a0.<\/p>\n

You can manage and update your system clock by hand, thanks to the command \u00ab\u00a0ntpdate\u00a0\u00bb <\/p>\n

\n
# date; ntpdate ntp.ubuntu.com ntp.univ-lyon1.fr ; date
 Tue May  5 22:38:16 CEST 2009
 5 May 22:38:17 ntpdate[12966]: step time server 91.189.94.4 offset -266.989213 sec
 Tue May  5 22:33:50 CEST 2009<\/pre>\n<\/blockquote>\n
Or you can let a deamon do that work for you.    <\/p>\n
# apt-get install ntp<\/pre>\n
The configuration file for the daemon is \/etc\/ntp.conf. I just added two servers to maximize the accuracy.<\/span><\/p>\n
\n
# echo -e \"server canon.inria.fr\\nserver ntp.univ-lyon1.fr\"  >> \/etc\/ntp.conf
# \/etc\/init.d\/ntp restart<\/pre>\n<\/blockquote>\n
 It’s really simple to manage your system time, but I had trouble for two days with ntpdate. I couldn’t syncrhonize my date, even if the command told me \u00ab\u00a0step time server blabla offset -blabla\u00a0\u00bb. Really annoying, and fortunately, I remember my system was a Xen client. So I searched this way. <\/span><\/p>\n
You have to say : \u00ab\u00a0my Xen client date is independant from the host\u00a0\u00bb :<\/p>\n
\n
# set independent_wallclock
# echo 1 > \/proc\/sys\/xen\/independent_wallclock<\/pre>\n<\/blockquote>\n
 Then you can run\u00a0 ntpdate, or let your deamon synchronize the system. It works!!!! <\/p>\n
Finally, I found many useful tips while trying to correct the xen issue.<\/p>\n