[SOLVED] Can't set date; manually, ntp or otherwise

JNat · 06-22-2011, 12:00 AM

Hey all,

Having an odd problem I can't seem to get sorted.

I've got ntp running, but unfortunately, I started it up before executing ntpdate to do the initial synchronizing of the OS clock to the "correct" remote server time. My VM had drifted badly over the months, so the offset when I run ntpq -p is currently -101 seconds, and continues to increase. I tried stopping ntpd, and running ntpdate again, however the sync was not successful; the offset persists.

I also tried to set the system date manually using the date command, however, it does not seem to work...when I run something like date --set="06/21/2011 1:00:00", it outputs that date, however when I execute "date" again, the date has not been changed. I'm logged in as root so that's not the issue.

I'm kind of at a loss at this point, do I need to uninstall ntp and reinstall or something? Thanks for any help.

Tinkster · 06-22-2011, 01:41 AM

Hi, welcome to LQ!

What's the host OS, what's the guest OS, what's the virtualisation
platform, and what hardware is this running on?

Cheers,
Tink

JNat · 06-22-2011, 11:47 AM

Hey Tink,

All I know right now is the guest OS, it's CentOS 5.5. I'm on a hosted VPS and I've not needed to know the other information thus far. I've got a request in to find out the other information. I'll post back here as soon as I find out.

JNat · 06-22-2011, 12:57 PM

OK more info from the VPS provider:

"The platform the VPS is on is running XenServer 5.6 with a 64-bit AMD CPU."

Still not sure about the host OS.

JNat · 06-22-2011, 01:02 PM

Here's what it looks like when I do ntpq -p...you can see the offset (second to last column) is 106 seconds:

remote refid st t when poll reach delay offset jitter
==============================================================================
+bindcat.fhsu.ed 128.138.140.44 2 u 6 64 377 72.918 -106493 22.501
+kallisti.us 198.82.1.203 3 u 19 64 377 100.123 -106476 24.267
*private.ssl119. .CDMA. 1 u - 64 377 88.069 -106470 23.025
LOCAL(0) .LOCL. 10 l 30 64 377 0.000 0.000 0.001

lithos · 06-22-2011, 01:17 PM

Hi,

what you can try to do is:

Code:

service ntpd stop
ntpdate pool.ntp.org  # wait till it sync's
#check time/date
date
#start ntpd again
service ntpd restart

ntpdate pool.ntp.org - you can use your nearest ntp server (list NTPPoolServers or here www.pool.ntp.org/en/ )

More about ntp_synchronize here.

Hopefully you will have time synced, but if your VPS gets time from host, then you're out of luck.

JNat · 06-22-2011, 01:22 PM

Hey Lithos,

Yeah, I already tried that a bunch of times. I think that the problem must be that the VPS gets its time from the host as you say. I'm working with the host now so hopefully they can help me resolve the issue. I'll post back when I find out for sure.

JNat · 06-23-2011, 11:36 AM

OK, I finally got it sorted out. I am on a VPS using Xen VMs. By default, the guest VMs will sync to the host machine's system time, so the guest VM is not able to alter its system time. Through much googling I found that this is controlled by a flag on the guest VM as described here:

http://support.citrix.com/article/CTX116376

Once I changed the flag value, I was able to run ntpdate successfully and now my system time is syncing properly.

Tinkster · 06-23-2011, 12:14 PM

Sweet ... thanks for coming back and posting the solution.
I'll move the post to Virtualisation, as it's really a problem
caused by the environment.

Cheers,
Tink