NTP and Ignite

[A. Daniel King_1]

Hi, folks.

Are there advantages to having your own host name in the NTP list for synchronization?

For instance, say I???ve got several almost identical servers I need to bring up in a quick fashion. I was planning to do my setup, make_tape_recovery the first machine, then boot from this ignite tape on the other machines. I imagine that I could change host names and IP???s and I???d be good to go.

However, my NTP theory is a little shaky. If I have ignite set up on the first machine, and the future names of the other nodes in ntp.conf as peers ??? once I???ve ignited, the initial node is missing from the mix.

Can this be handled by simply adding the initial host name as a peer to itself?

Are there any dangers to doing this?

For example:

Primary ntp host (will not change): atl0
host1 (for ignite source): atl1
host2 (to be ignited): atl2
host3 (to be ignited): atl3

Proposed initial ntp.conf on atl1:

server atl0 version 3 prefer
peer atl1 version 3
peer atl2 version 3
peer atl3 version 3
server 127.127.1.4 minpoll 3 maxpoll 4 # Is there an advantage to this line all?
fudge 127.127.1.4 stratum 10 # Or this?
driftfile /etc/ntp.drift # path for drift file

Thanks.

[Michael Steele_2]

By designating :
server 127.127.1.1
fudge 127.127.1.1 stratum 10

You are configuring the NTP master server for the local network intranet. These entries are made within the /etc/ntp.conf file. Set your netdaemons file, start the xntpd daemon and wait ~5 minutes.

Prior to setting your NTP master server you go to your clients and use the date command to add ~3 minutes ahead to the clients system time.

Afterwards, you go to each NTP client's /etc/netp.conf file and use the server's ip address:

server
driftfile /etc/ntp.drive

Also update your netdaemons file and start NTP:
/sbin/init.d/xntpd start

[A. Daniel King_1]

Frederick, this is all true.

However, atl1 is not the primary ntp server. Is there any advantage to having an external master defined as well as the local clock? Even at a higher numbered stratum? atl0 is the primary ntp source.

The idea, though, of, "go to your clients" is something I'd like to avoid by using ignite.

The ntp.conf file will be duplicated to all the clients, for which I perceive an advantage in having all as peers.

Am I wrong? Is there a maximum number threshold of "peers" which is unhealthy?

[Michael Steele_2]

I'll have to research this but off the top of my head it sounds like everyone would be a backup master server pointing to themselves. Consequently, it sounds like you've come up with a new form of recursion using NTP. In short, if everyone's syncing up to themselves, aren't they already doing this without using NTP?

[Michael Steele_2]

OK, I don't think you need to worry about the above. Because when you clone your servers using ignite you have to interrupt the automatic recovery sequence and choose the advanced installation options. You will be asked during this procedure the same questions that you're asked when using the 'set_parms initial' command. What are your default gateway, hostname, ip, NIS server and NTP server?

Because of this, ntp.conf will be rebuilt with every installation or left blank if you choose to ignore the answers. Look at /usr/newconfig/etc/ntp.conf for an example of the blank or default ntp.conf file.

So, how many peer NTP servers becomes a moot question during the ignite installation since you will be asked to enter your master NTP servers at this time.