Two nodes with same hostname

[kokoticek]

I think I made a probably big mistake, I'm worried and I'm in need for help...

I have a Proxmox VE 4.4 server which was installed some time ago, but I remember during installation I put domain name as "pve.domain2.com". This server has ip 10.0.0.2. In /etc/hosts, among other lines, I see
10.0.0.2 pve.domain2.com pve pvelocalhost
But if I type command "hostnamectl" to display current hostname I get:
pve

Today I just installed a new server with Proxmox VE 5.1, with ip 10.0.0.3 but with domain "pve.domain3.com". Yes, this one needs different domain, but for now both servers are in the same network segment.
Its /etc/hosts file shows the corresponding changes for ip and domain name, but the command "hostnamectl" gives the same!
pve

For some strange reason the 5.1 server never gave any network error or warning. I have no idea about the 4.4 server since I was not able to check it, I was a bit too far from it. But I freaked out, powered off both servers then just turned on 5.1 one.

Is there harm or consequences for both server for having been both powered on at same time, in same network segment, with same hostname?
I haven't created/configured any clusters at all whatsoever, by the way.
If so, how can I fix? Just when I was thinking to upgrade the 4.4 one to 5.1 according to wiki instructions...

thanks

 

[jim.bond.9862]

you can not have any machines with the same names on the network.
DNS gets confused. it is a good practice to have a good meaningful name for any machine unless it is a temporary test setup that will be discarded fast.
"pve" is not a good meaningful name. so , leave the original server be for now, I suspect you plan to reinstall it when it's time to upgrade.
reinstall the new setup and give a good name to it. even pveNode2 is better then pve when you have more than one.

when reinstalling the older server give the name pveNode1 to be consistent and keep it in line.

 

[kokoticek]

You only stated what you want me to freaking do, you did not help at all nor was your intention!
Can someone else help please?

For some strange reason the 5.1 server never gave any network error or warning. I have no idea about the 4.4 server since I was not able to check it, I was a bit too far from it. But I freaked out, powered off both servers then just turned on 5.1 one.

Is there harm or consequences for both server for having been both powered on at same time, in same network segment, with same hostname?
I haven't created/configured any clusters at all whatsoever, by the way.
If so, how can I fix?

 

[jim.bond.9862]

You only stated what you want me to freaking do, you did not help at all nor was your intention!
Can someone else help please?

First of all, there is no need for profanities.
Second, I did answers your question, even if just partially.
Read my post.
I told you:

A. It is not good nor correct to have multiple host with the same host name.

B. I told you why it is not good
C. I gave you an idea for a proper acceptable host names you can and should use.
D. I told you, what you can do to resolve the situation, as in
Leave the older host as is and reinstall proxmox on new host using new naming convention.
Or try simply editing the hosts file and reboot. But that maybe problematic as proxmox sometimes have issues if you rename host after install.

Sorry I can not give you a line by line script or commands.
Except RTFM.

 

[kokoticek]

I began with the wrong foot, and would like to please ask for another different opinion

There's Proxmox VE 4.4 server which was installed a while ago; during installation I put domain name as "pve.domain2.com". I normally changed only the domain part because there's normally only one Proxmox server per place, so never worried about the left-most part of fqdn, which I only recently discovered it becomes PC's hostname.
IP address: 10.0.0.2
hostname: pve ---------- (as displayed by "hostnamectl status" command)
/etc/hosts: 10.0.0.2 pve.domain2.com pve pvelocalhost --- (plus all other loopback and commented lines)

Then recently I installed a new server with Proxmox VE 5.1, which is aimed for another different place but requires to be ready-to-go, so I "initialized" it just here. Domain name is "pve.domain3.com".
IP address: 10.0.0.3
hostname: pve ---------- (as displayed by "hostnamectl status" command)
/etc/hosts: 10.0.0.3 pve.domain3.com pve pvelocalhost --- (plus all other loopback and commented lines)

So I had to connect 5.1 one in same network segment as 4.1 one, but it was too late when I just realized both servers had same hostname despite having different domains. It was NOT intentional.

I haven't created/configured any clusters at all whatsoever on any of the servers.

Is there harm or consequence for both server for having been both powered on at same time, in same network segment, with same hostname?
Apparently they did not display any error/warning, but what if there was invisible damage or only at background level? I'm not allowed to re-install any of the servers anymore, only upgrade them at most!

 

[jim.bond.9862]

There is no damage, and if it is a temporary situation, I.e. you just want to test the setup and finalise it. It should be ok.
But I would not advise to run the new server for long time like this.
If any thing on your network uses host name to access your old server it might get a big surprise once in a while by connecting to the new one.

In a windows active domain setup for example you would get an error as soon as networking is up.
And I bet if you look into logs you might see a warning about it.
It is not an issue until any one of this machine needs to talk to the other.
Or until some other device needa to talk to one of them amd only uses the host name to connect.

That are the only side effects of this situation. And maybe a bunch of errors/warnings in your DNS server ip4 stack.