Comment 42 for bug 114505
Revision history for this message
| cwsupport (netsupport) wrote Re: [Bug 114505] Re: ntp brought up before network is ready; fails not resolve any ip or host names; ntp does not recover | #42 |
Hi,
I disagree with this diagnosis..
S28NetworkManager is a red-herring. For a start Hardy doesnt have
this...Looking at the startup for Hardy:
S15bind9
S16openvpn
S16ssh
S17mysql-ndb-mgm
S17portmap
S18avahi-daemon
S18mysql-ndb
S19mysql
S20apmd
S20apport
S20cupsys
S20cyrus2.2
S20exim4
S20hotkey-setup
S20jboss
S20nfs-common
S20nfs-
S20nvidia-kernel
S20powernowd
S20rsync
S20samba
S20saslauthd
S20ser2net
S20winbind
S20xl2tpd
S23ntp
As you can see S23ntp is up WAY after bind9. DNS clients resolving using
gethostbyname() only need the network up - and on worst case (i.e. my
machine with a caching DNS server) it needs to be up after S15bind9. It
seems to me the problem is that NTP is run before the *network* cards
are brought up properly (certainly before eth0). By the time it hits
S23ntp the damage was already done a long time before.
Resolution is based around /etc/nsswitch.conf, /etc/hosts and
/etc/resolv.conf. As it happens I am running caching DNS servers (bind9)
on all these machines as well - to fail to obtain the host that means
NTP is being executed PRIOR to S15bind9.
Now I have to say...the situation with the NTP daemon is a farce and
there have been so many people 'tampering' with NTPD startup that quite
frankly the use of /etc/rc2.d scripts is being completely undermined.
What is needed is a proper solution here rather than yet more tampering.
The NTP daemon is being started already from around 3 different places.
It is the ordering and interaction of these which is causing the
problems - coupled with the fact that the NTP daemon itself does not
perform any kind of retry-recovery internally.
Thomas wrote:
> I just finished a fresh U8.10-rc install.
> Plain vanilla, all I added was the NTP package.
>
> sprinkmeier@u810:~$ ls -l /etc/rc5.d/S2[38]*
> lrwxrwxrwx 1 root root 13 Oct 26 14:18 /etc/rc5.d/S23ntp -> ../init.d/ntp
> lrwxrwxrwx 1 root root 24 Oct 26 10:10 /etc/rc5.
>
> NTP starts before Network Manager, meaning that NTP won't have DNS available at startup.
> It tends to work, but moving NTP's startup after Network Managers should make it more reliable. It will also allow NTPDATE to run (it's called from the ip-up scripts, but will fail as NTPD will already own the socket).
>
> sprinkmeier@u810:~$ grep ntp-server /etc/dhcp3/
> sprinkmeier@u810:~$
>
> NTP servers still aren't requested by default. If whoever set up your
> DHCP server knows enought to advertise NTP server(s) then chances are
> you should use them (or at the very least PREPEND them).
>
>
--
Sincerely Yours
Copyright Witness Net Support
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