Is it possible to change the IP address of checkmk server

General
1

Hi Team,

We have checkmk(Checkmk Raw Edition 2.1.0p18) running on a physical server with installed OS as Ubuntu20.04 LTS.

Now due to some network reorg, is it possible to change the IP address of checkmk server?
We have only one site instance and that would be same, I mean no change in URL …only want to change the IP address of checkmk server.
We have total 431 host and 10786 services.

BR
//Prachi

2

Hi,
well as far as I know you only need to change IP of your server on which cmk is installed and done. Of course you must change address in firewall if you use any.

Best regards,
JF

3

Hi Prachi

Extending what @jan.filo said, make sure to also update:

  • the “Only from” setting of the agent on the monitored hosts, if you use this setting
  • any “allowed hosts” or similar on any monitored device that might use this (this is often found on SNMP devices)
  • any SNMP trap destination pointing to your old IP address

I would recommend extending these prior to swapping the IP address. Otherwise you will get a lot of errors in Checkmk. Once the swap has been done, you can then safely remove the old IP address everywhere.

Kind regards

4 Likes
4

Oki…thank you team!!

Will try this on a test server first by installing a site, adding few agents and then changing the IP…and verify if the URL works!!

Would get back to you in case of concerns.

BR
//Prachi

2 Likes
5

You would need to modify all rules where you have specified original ip address. For example in Agent Bakery, if you use it. And then re-register all servers again. If you use DNS everywhere in rules, should be fine, then just re-register servers.

I was moving our main instance from on-prem to cloud few days ago. And had to do all above things.

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6

Hi,

Today created a test Ubuntu 20.04LTS VM and installed Checkmk Raw Edition 2.1.0p18 and then changed the IP address of Ubuntu after which I am able to access the VM but unable to access the Checkmk GUI.
Also, I am accessing the GUI with server name and server name is as it is. Only we have changed the IP.
If I roll back to original IP , able to access the GUI but when the IP is changed GUI is not accessible.

1.My firewall is disabled.
2.omd status is running.

What else need to be checked , please guide me!!

BR
//Prachi

7

Hi Prachi,

I am currently on the road, so I cannot test this, but you could give

omd update-apache-config mysite

a try.

8

Hi,

Thank a ton for the quick acknowledgement.

Yes even after trying the command unable to access checkmk GUI with the servername. Although I am able to access the site with the changed IP(new IP) but not the servername…

Also when I did nslookup and could see the old IP instead of new one…literally confused in Ubuntu.

But let me know after you test!!

BR
//Prachi

9

Hallo,
be aware of firewall rules and other filters etc. if you are monitoring separated networks like a DMZ or a network via VPN.
Ralf

10

Hi,

Yeah, tried everything, but I feel it’s better to do complete server migration instead of changing the IP.

We have total 431 host and 10786 services.

BR
//Prachi

11

Hi,

are you sure, that you changed the ip of the hostname in your DNS server accordingly, when doing the tests ? It sounds your DNS was still pointing to the old address.

Also when testing locally, on the checkmk look in your /etc/hosts and in particular on ubuntu use the correct tools (netplan and hostnamectl) and check if everything is set correctly there.

Keeping in mind, what the others have already listed in terms of dependencies, i would NEVER migrate a checkmk installation if the only reason for that is to change the ip of the server.

2 Likes
12

Hi,

Agreed to you, my bad, the DNS update in my organization takes some time around 8 hours.
Absolutely, in my test PoC we can successfully migrate the IP address of checkmk and the GUI will work both with IP and server name.

Next step in my PoC would be to validate the checkmk agents and see how it behaves after changing the IP address of checkmk server.

We can close this discussion.

Thank you!!

BR
//Prachi

13

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