Good afternoon!
I have Home Assistant OS installed on a Raspberry Pi 3, and I added the UniFi Controller add-on, but the log shows the following error: “Out of memory: Killed process 2988 (java)”.
I tried version 5 of the UniFi add-on, but it always shows the same error.
In the configuration, I have two parameters (memory_init and memory_max) — I tried lowering the values, but I still get the same issue.
Is there any way to get the UniFi Controller working on the Pi 3?
Has anyone managed to run it successfully?
I have several Pi 3 boards and would like to reuse them with Home Assistant.
Thank you!
A RPi 3 has barely enough CPU and memory to run Home Assistant OS. Trying to run the modern UniFi Network controller app on top of that is probably just too much for a 9+ year old RPi3.
Since you mentioned having multiple RPi 3 boards - why not use one for HAOS and another for the UniFi Network app? The one running UniFi Network would need to be hosted on a barebones Linux install, to try and free up as many resources as possible to run the UniFi Network App. I am not sure if even then it will have enough resources…
Honestly HA is almost too much for a Pi3 by itself… Yes it’s listed as system minimum config but… Unless it’s a studio apartment with a small install… I probably would go for something bigger to start.
It is not listed as a minimum config anymore and has not been for some months now. Today it is mentioned with a note that it has too low memory to run HAOS.
Before it was listed with a warning that it could only the most basic setups.
I have an RPi 3B+ and I have to agree. I’m shopping for new hardware now.
Ironically, HA only uses single-digit CPU percentage. It’s the memory which gets squeezed tighter and tighter with every new HA version. Too bad they didn’t add a memory expansion slot on those things. It’s also frustrating that it takes more memory to do the exact same thing every month, but I get that nobody wants to waste their time generating efficient code any more.
In fairness, I should mention that after my last update (to HAOS 15.2 and Core 2025.5.3) I saw about a 10% drop in memory utilization.
Impressive! And a welcome change in the previous pattern. That said, HA is not really designed for efficiency. But in all fairness, nothing is these days. And certainly nothing written in a high-level language. There are just too many external libraries and too many layers of abstraction. Memory and CPU cycles are cheap, and high-level languages are easier to use, so I totally get that efficiency isn’t a priority. It’s just frustrating when the hardware you bought shiny and new becomes unable to do the tasks it used to perform effortlessly. I guess it’s a good excuse to buy new hardware, which, admit it, we all love to do.
