NTP Server issue

Operating Systems Linux Red Hat NTP Server issue

09-24-2013

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It is possible to have a NTP server running on VMware (5.1 in my case). But you have to make sure, that the host's clock is close to accurate, meaning ESXi's NTP client has to be configured properly.

That's because a VM syncs its time with the host at boot time, even if timesync is disabled in the VMs configuration. Now if the host's time is off by a greater timespan, the guest's clock is off too, because of the boot-time timesync with the host and the NTP daemon will not be able to adjust the guest's clock and synchronize to it's upstream NTP servers.

Last edited by hergp; 09-24-2013 at 06:55 AM.. Reason: some rephrasing

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LEARN ABOUT OSF1

ntptrace

ntptrace(8)						      System Manager's Manual						       ntptrace(8)

NAME

       ntptrace - Traces a chain of NTP hosts back to their master time source

SYNOPSIS

       /usr/sbin/ntptrace [-dnv] [-r retries] [-t timeout] [server]

OPTIONS

       Turns  on  some	debugging output.  Turns off the printing of host names; instead, host IP addresses are given.	This may be necessary if a
       nameserver is down.  Sets the number of retransmission attempts for each host; default = 5.  Sets the retransmission timeout (in  seconds);
       default = 2.  Prints verbose information about the NTP servers.

DESCRIPTION

       The  ntptrace  command determines where a given Network Time Protocol (NTP) server gets its time from, and follows the chain of NTP servers
       back to their master time source. If given no arguments, it starts with localhost.

       The following is an example of the output from ntptrace: % ntptrace  localhost:	stratum  4,  offset  0.0019529,  synch	distance  0.144135
       server2.bozo.com:  stratum  2,  offset  0.0124263, synch distance 0.115784 usndh.edu: stratum 1, offset 0.0019298, synch distance 0.011993,
       refid 'WWVB'

       On each line, the fields are (left to right): the host name, the host's stratum, the time offset between that host and the local  host  (as
       measured  by  ntptrace;	this  is  why  it  is not always zero for localhost), the host's synchronization distance, and (only for stratum-1
       servers) the reference clock ID.  All times are given in seconds. (Synchronization distance is a measure of the	goodness  of  the  clock's
       time.)

SEE ALSO

       Commands: xntpd(8), xntpdc(8)

																       ntptrace(8)

Red Hat