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Benoît
Asked: 2010-07-14 08:00:30 +0800 CST

How do i smoothly update ntpd's peer list?

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I have a network of solaris/linux servers that have ntpd configured to use a single internal server of stratum 2 through a DNS alias/CNAME. This is server is down for some time and the client servers' clocks are out of sync.

Since we have another internal server of stratum 1 (PPS), the DNS CNAME has been modified to point to the new server (which is up).

But using ntpq -p i can see that the client servers are still pointing to the old server. It looks like they are not resolving again the peer name, so they don't get the new server IP.

How do i smoothly update ntpd's peer list ?

If i restart (x)ntpd, it's going to create timejumps. I wish ntpd would have updated its peer list / configuration and smoothly synced with the new server.

linux domain-name-system solaris cname-record ntpd

2 Answers

  1. Best Answer

    ntpdc can do this for you -- specifically the addpeer and unconfig commands.
    Basically update your config file, then use ntpdc to add the new peers and remove ("unconfigure") the old ones (after ntpd accepts the new peers as sane candidates for synchronization!)

    You should also consider using a redundant device (routers with HSRP, or unix machines with HA failover/CARP/etc.) as your NTP source, or configuring more than one peer -- You don't want your clocks going insane just because one time server has a problem...

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  2. If said servers are configured via DHCP (which they are, for easy renumbering, right? :) ) then you can update the DHCP server to send option 42 with the new server address. They should all reacquire their leases (and get updated) at some point, right?

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