Changing host info w/o rebooting

[Jennifer Young_1]

I need to change the hostnames on a few HP 9000's and have them realize that the name of the domain they are in has changed, as well as the name of their DNS server. The ip's will stay the same. I'd like to just run set_parms, but I can't reboot these machines at my leisure.

Are these the right steps to follow without rebooting?

1. Change the hostname and DNS server name in /etc/hosts
2. Change the domain name in /etc/resolv.conf
3. Change hostname in /etc/rc.config.d/netconf

then run:
4. hostname

Thanks for any replies!

[Jitendra_1]

I think you got it right. The important one was /etc/rc.config.d/netconf which is often forgotten.

[Bruce Regittko_1]

Hi,

Yes, the steps you have will change the hostname, however, you may have problems if you don't reboot.

Some applications read the hostname when they are launched and won't recognize that the hostname has changed. CDE, for example, becomes very ill when the hostname is changed. To "really" change the hostname, you should reboot.

--Bruce

p.s. You may also want to run

uname -S

which sets the node name (system name) that is used in the utsname structure. See the uname manpage for more information.

[Tim Malnati]

My best suggestion is to try to avoid hostname changes like the plague. There are many monitoring facilities that use it (like MeasureWare) and remote interfaces can sometimes get problematic too (like remote SAM). One of the selling points for using DNS is to be able to change an ip address seamlessly, not the other way around. If possible you are better off using an alias in DNS instead if you can get away with it. How many remote clients access this machine using DNS? There is a good chance that you will end up needing to add an alias to DNS from the old hostname to take care of this problem which sort of gets you the question of what's the point?

[Dan Hetzel]

Hi Jennifer,

I hope you're not running Oracle on your servers. The hostname is hard-coded in the database file and you'll have to ask your dba to fix this...

I agree with Tim when he's saying "changing a hostname should be avoided like the plague".

Good luck,

Dan

[marc seguin]

I never had problems when changing the hostname with
/sbin/set_parms hostname
but it needs a reboot at the end...

[Philip P. Hartl · Accepted solution]

Caution: As pointed out the hostname is used by various applications, however not even a reboot will resolve problems caused by changing the hostname in many cases. Case in point, OMNIBACK uses the hostname as a Cell Name in the database. Following a hostname change OMNIBACK will likely not recognize the new and lose track of the old Cell. To correct this run "omnidbutil -change_cell_name [ -old_host ]".