[CentOS] ntpd stuck on stratum 16 = not synced

Wed Jan 16 17:35:36 UTC 2008
Paul Heinlein <heinlein at madboa.com>

On Wed, 16 Jan 2008, Sean Carolan wrote:

> Maybe there's an ntp expert out there who can help me with this.  I 
> have an NTP server serving our local network.  It is set up to use 
> pool.ntp.org servers for it's upstream sync.  ntpq -p reveals that 
> the server is stuck on stratum 16, which I understand means "not 
> synced".  The clients are unable to sync with my local server 
> because of this.  Here's the output of ntpq -p along with my 
> ntp.conf file:
>
> [root at ntpserver /root]# ntpq -p
>     remote           refid      st t when poll reach   delay   offset 
> disp
> ==============================================================================
>  echo.sureproxy. 0.0.0.0         16 u   29   64    0     0.00    0.000
>  16000.0
>  nist.netservice 0.0.0.0         16 u   19   64    0     0.00    0.000
>  16000.0
>  ntp.your.org    0.0.0.0         16 u   19   64    0     0.00    0.000
>  16000.0
>  ntp.pbx.org     0.0.0.0         16 u   19   64    0     0.00    0.000
>  16000.0

Name resolution is working correctly, but, yeah, there's no sync-ing 
happening.

> #  Drift file.  Put this in a directory which the daemon can write to.
> #  No symbolic links allowed, either, since the daemon updates the file
> #  by creating a temporary in the same directory and then rename()'ing
> #  it to the file.
> # 
> driftfile /etc/ntp/drift

This is almost certainly incorrect unless you're running a very, very 
old RHEL/CentOS release. I believe /var/lib/ntp is the canonical 
directory for the drift file in 4.x and 5.x. I doubt ntpd is allowed 
to write to /etc/ntp, especially if SELinux is enabled.

Have you tried shutting down ntpd and relaunching it manually with the 
"don't fork and give me lots of debugging output" switches (-n -ddd) 
enabled?

Alternatively (or additionally), you might try wrapping ntpd in strace 
to see if any system calls are being thwarted.

-- 
Paul Heinlein <> heinlein at madboa.com <> http://www.madboa.com/