Setting up a local stratum 2 NTP server
I'm trying to setup NTP on a local network that has no (and never will) internet connection. The main priority is that the machines on the network are synced with each other, even if the time they're synced at isn't 100% accurate.
We also have a requirement to use an NTP hierarchy in order to replicate the setup of a deployed system. What I want to do is have a hierarchy of machines like this:
Moon (Main Server running Windows) (10.1.3.10)
|____Earth (Linux x64 client) (10.1.3.1)
|____Mars (Linux x64 client) (10.1.3.2)
|____Saturn (Linux x64 client) (10.1.3.3)
|____RackCard23 (Linux x64 client and server to the two machines below) (10.1.3.23)
|___RackCard21 (Linux x64 client) (10.1.4.21)
|___RackCard22 (Linux x64 client) (10.1.4.22)
Note that the RackCards have two ethernet ports, one connected to the 10.1.3.x network and one on the 10.1.4.x network. RackCard23, which syncs off the master server Moon will do so on the 10.1.3.x network and the RackCard22/23 will connect to RackCard23 on the 10.1.4.x network. This is because I don't want the RackCards22/23 leaving their network to sync the time and because it replicates a final deployed system.
So far I have managed to get everything that should by syncing off Moon to sync correctly (including RackCard23).
But I am having difficulty getting RackCard22 and 23 to sync off RackCard23.
[root@RackCard23]# cat /etc/ntp.conf
# NTP Deamon Configuration File "ntp.conf"
# Created on 27/04/2010
# Original backed-up as "ntp.conf.backup"
server 10.1.3.10 iburst minpoll 4 maxpoll 4 prefer #This is what we want to happen
fudge 127.127.1.0 stratum 2 #Not sure about these two lines, was trying to force it to be a stratum 2 server
fudge 127.127.0.1 stratum 2
# 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 /var/lib/ntp/drift
restrict 10.1.3.10 mask 255.255.255.255 nomodify notrap noquery
#Attempt to get to act as an NTP Server
broadcast 10.1.4.255
restrict 10.1.3.21 mask 255.255.255.255 nomodify notrap
restrict 10.1.4.21 mask 255.255.255.255 nomodify notrap
This is the output from ntptrace:
[rootRackCard23]# /usr/sbin/ntptrace
localhost.localdomain: stratum 16, offset 0.000000, synch distance 0.000030
As you can see the machine is reporting itself as a stratum 16 server, despite it having been synced to a "stratum 1" server (Moon):
[root@RackCard23 awd]# /usr/sbin/ntpdate -d 10.1.3.10
21 Jun 13:55:09 ntpdate[19410]: ntpdate [email protected] Tue May 19 13:57:56 UTC 2009 (1)
Looking for host 10.1.3.10 and service ntp
host found : 10.1.3.10
transmit(10.1.3.10)
receive(10.1.3.10)
transmit(10.1.3.10)
receive(10.1.3.10)
transmit(10.1.3.10)
receive(10.1.3.10)
transmit(10.1.3.10)
receive(10.1.3.10)
transmit(10.1.3.10)
server 10.1.3.10, port 123
stratum 1, precision -6, leap 00, trust 000
refid [LOCL], delay 0.04135, dispersion 0.00383
transmitted 4, in filter 4
reference time: cfc99402.e010624d Mon, Jun 21 2010 8:32:18.875
originate timestamp: cfc9dfad.48000000 Mon, Jun 21 2010 13:55:09.281
transmit timestamp: cfc9dfad.47e27179 Mon, Jun 21 2010 13:55:09.280
filter delay: 0.04155 0.04155 0.04137 0.04135
0.00000 0.00000 0.00000 0.00000
filter offset: -0.01448 0.000781 0.000537 0.000394
0.000000 0.000000 0.000000 0.000000
delay 0.04135, dispersion 0.00383
offset 0.000394
21 Jun 13:55:09 ntpdate[19410]: adjust time server 10.1.3.10 offset 0.000394 sec
The configuration of the clients (RackCard21/22) looks like this:
[root@RackCard21]# cat /etc/ntp.conf
# NTP Deamon Configuration File "ntp.conf"
# Created on 27/04/2010
# Original backed-up as "ntp.conf.backup"
server 10.1.4.23 iburst minpoll 4 maxpoll 4 prefer
server 127.127.1.0
fudge 127.127.1.0 stratum 10
# 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 /var/lib/ntp/drift
# restrict 127.0.0.1
restrict None mask 255.255.255.255 nomodify notrap noquery
And ntptrace gives this:
[root@RackCard21]# /usr/sbin/ntpdate -d 10.1.4.23
21 Jun 14:04:34 ntpdate[14381]: ntpdate [email protected] Tue May 19 13:57:56 UTC 2009 (1)
Looking for host 10.1.4.23 and service ntp
host found : 10.1.4.23
transmit(10.1.4.23)
receive(10.1.4.23)
transmit(10.1.4.23)
receive(10.1.4.23)
transmit(10.1.4.23)
receive(10.1.4.23)
transmit(10.1.4.23)
receive(10.1.4.23)
transmit(10.1.4.23)
10.1.4.23: Server dropped: strata too high
server 10.1.4.23, port 123
stratum 16, precision -20, leap 11, trust 000
refid [10.1.4.23], delay 0.02568, dispersion 0.00000
transmitted 4, in filter 4
reference time: 00000000.00000000 Thu, Feb 7 2036 6:28:16.000
originate timestamp: cfc9dfef.12b79516 Mon, Jun 21 2010 13:56:15.073
transmit timestamp: cfc9e1e2.aeae7d56 Mon, Jun 21 2010 14:04:34.682
filter delay: 0.02573 0.02571 0.02568 0.02568
0.00000 0.00000 0.00000 0.00000
filter offset: -499.609 -499.609 -499.609 -499.609
0.000000 0.000000 0.000000 0.000000
delay 0.02568, dispersion 0.00000
offset -499.609286
21 Jun 14:04:34 ntpdate[14381]: no server suitable for synchronization found
So it can't find a suitable server because the server I'm trying to use is reporting that it is a stratum 16 server (which I believe means non-synchronized). This is despite the fact that it is synchronized.
So I need to somehow make RackCard23 a higher stratum (Ideally stratum 2). How do I go about doing that?
Any help is much appreciated as I have been trying to get this to work for days now!
EDIT:
Hi Christopher,
I have been restarting the ntpd, yes ;)
All the linux boxes are running CentOS 5.4.
This is the output from the commands you suggested. Firstly from the server:
[root@RackCard23]# /usr/sbin/ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
10.1.3.10 .INIT. 16 u - 16 0 0.000 0.000 0.000
10.1.4.255 .BCST. 16 u - 64 0 0.000 0.000 0.001
[root@RackCard23]# /usr/sbin/ntpdc -c monlist
remote address port local address count m ver code avgint lstint
===============================================================================
localhost.localdomain 34566 127.0.0.1 1 7 2 0 0 0
10.1.4.21 123 10.1.4.23 5 3 4 180 5 1
10.1.4.22 123 10.1.4.23 7 3 4 0 2 2
And then from client:
[root@RackCard21]# /usr/sbin/ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
10.1.4.23 .INIT. 16 u 10 16 0 0.000 0.000 0.000
LOCAL(0) .LOCL. 10 l 44 64 1 0.000 0.000 0.001
Solution 1:
As Chris mentioned, the stratum 16 indicates a server hasn't actually sync'd with a server. Just to be certain, you did restart the ntp services, right? (service ntpd restart) I'm not trying to insinuate you miss the easy stuff, but I always do!
Can you post the output of a few more commands to help diagnose?
ntpq -p on the client & server. Should show what servers it has configured, as well as stats for those servers.ntpdc -c monlist on the server. Should show the clients connected.
Also, since you didn't mention an OS, I'm running with RHEL style commands. Let me know if you've got something different.
EDIT after further info
OK, seeing your output, here's your problem: You don't have a stratum 1 server. In fact, the "Moon" is using it's local clock. It's reporting itself as a stratum 16 server. For your reference, a Stratum1 server would have a local GPS or atomic clock. Do you have one of those? Otherwise, Moon needs to synchronize it's clock with ANOTHER ntp server. If it doesn't have network access, you'll need to fudge its stratum. (This requires you not to care too much about 'true' time. Which you don't, but anyone else reading this should note that.)
On Moon, add the following line to your ntp.conf file: fudge 127.127.1.0 stratum 10. This will make it report its local clock as stratum 10. Which will make all the other servers use it over their local stratum 16 clock.
--Christopher Karel
Solution 2:
May be out of topic, a local Stratum 2 server requires connection to a Stratum 1 server and within your isolated network, you don't have one.
You can get a cheap GPS module and an Raspberry Pi, a single-board computer with minimal power consumption and ample interfacing capability. Hook your GPS module to the Raspberry Pi and join the Pi into your network, with proper software, it can be your Stratum 1 NTP server that your Stratum 2 server, or since you have it inside your network every computer, sync time with.