Temporarily adding 2nd RPi with Home Assistant to LAN

I have heard there’s a plugin that allows adding a 2nd and subservient instance of Home Assistant on a LAN. I just want to be clear this is NOT what I want to do.

I want to setup, on my LAN, a 2nd Pi with HA on it for some simple tests. I know when it runs and talks to my LAN DHCP, it’s going to give its name has “homeassistant,” just like my current Pi with HA does. I’d like to be able to use the web control interface to add integrations and set up this 2nd HA instance and not have any interference with my current HA on another RPi.

Is there a way to easily change the hostname on the 2nd HA instance? Or is there a better way to keep the two from interfering with each other? (I do not plan on trying to control devices with this new instance for a while - and when/if I do, then I’d be removing the old instance.)

If you plan on using Home Assistant Operating System

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But that’s from the web interface, right? I’m a bit worried about if I can get there with two systems with the same name asking for an address from the same DHCP server.

You can. Just use the ip address instead of homeassistant.local. Then after you change the hostname you can use <hostname>.local. I have two dev systems I set up on my network this way alongside the main one.

Also just for reference the DHCP server doesnt really care what it’s hostname is or that it’s unique. The .local thing is mdns which doesn’t involve DHCP at all. You won’t mess up anything.

Thanks! that answers all my questions (spoken or unspoken) all at once!

The current system is a Frankenstein system that replaces one that went bad, so it’s got configuration files that probably should not have been copied over directly. (I had problems with my backup RAID - after one storm, we lost internet for a day or two, the HAOS system went bad, and that share on the RAID had issues. (Fortunately the rest of the RAID was okay!) Oh, and I had to redo my firewall. Still not sure exactly what went wrong!