Yes it can be done with an rpi4 but you still need an SD card in the rpi with the boot partition, then everything else runs from the SSD

www.stewright.me/2019/10/run-raspbian-fr...on-a-raspberry-pi-4/

Set up swap now on an SSD while running the OS from the SD card. Works great and no more crashes when building Kstars from sources.

Hi,
i installed 20.04 server (x64)on my RPi4 whith kstars, astrometry, indiwebmanager

The only thing that doesn't install is sextractor :
librairy files are there when i seach with find command. But the binary in usr/bin isn't there
I tried both from ppa and astropi3 script...And sextractor binary is still missing
I thought that i will be installed with kstars...
Is there an another way to install it without cloning kstars Git ?

Clear skies

On Ubuntu 20.04 the command has been renamed to source-extractor. The full path is

EDIT: the software package also has been renamed to source-extractor:


HTH, Wouter

Thanks Wouter!
I used the find command and only gives me library files.

I'll check again

Clear skies

I am not a big fan of MATE being such a complete Desktop. Basically I want a minimalistic desktop without open/libre office, thunderbird etc. So I usually install ubuntu-mate-core instead of ubuntu-mate-desktop. Saves a lot of files to download and saves on disk space as well which then can be used to fill with images

EDIT Ubuntu automatically installs a daemon called snapd which is completely useless and only consumes system resources. Remove it with "sudo apt purge snapd squashfs-tools" and then do "sudo apt-mark hold snapd" to make sure that it cannot be installed again.

Wouter

You can do this without taking the SD card out while Ubuntu is running:

sudo vim /boot/firmware/usercfg.txt

Or open a terminal and type

sudo lightdm-settings

and go to the Users tab and fill out your username (ubuntu by default on Ubuntu Server but you can rename the user if you like and this also works on other versions of Ubuntu with lightdm installed).

Thanks for the great write up!!!!


Wouter

Thanks Wouter,
I found out later that there are two usercfg.txt files, one in the system-boot partition (for modifying that you need to take out the SD card) and one in the boot/firmware folder. When I wrote up the instructions, I had not been aware that that one would also be used during boot up from the SD card.
Thanks also for pointing out the short-cut using the lightdm-settings command.
Overall, the setup is pretty painless. I still prefer the full MATE desktop, though, over just installing the core, as it contains a few more tweaks I like in MATE which I otherwise have to install separately, but that is a matter of individual taste.
Jo

Just out of curiosity, what are those tweaks? Maybe I am living my life while missing out on some interesting ways of using Ubuntu...


Wouter

Backgrounds, screensavers, panel items, various applications prepopulated in the menu I have gotten used to. Nothing you need to run Kstars.
I just like to set up Ubuntu on the Pi in much the same way as I have it on my desktop, saves me time navigating. At home, I am mostly using Ubuntu, I use my Mac almost exclusively for work (Word, Powerpoint, Excel, Endnote, Acrobat - none of the LibreOffice equivalents are compatible enough to port from Linux to Mac or Windows). One reason why I may have drifted that way is that my desktop has 32 GB of RAM and 8 cores, my Macbook Air only has 8Gb and it is getting a bit slow these days.
I had gone the route of minimal installation before and ended up spending a lot of time identifying the components I was missing and had gotten used to, then installing them one by one.
As I wrote, it is mainly a matter of personal taste. If you want to run the RPi4 lean and mean, that certainly should help its performance with Kstars, but I find that it is plenty powerful and performance does not suffer by installing these other tweaks, unless you are running memory intensive tasks like multiple Firefox windows etc. at the same time you are trying to run Kstars. That could be a problem. And with a large memory card, like a 128 Gb microSD card or with an external SSD connected for saving images, the 2 or 3 Gb of additional space it takes no longer is a factor.

OK, thanks. Just checking.

Downloading the Ubuntu image and burning to SD is now much easier with the Raspberry Pi Imager. Download from www.raspberrypi.org/downloads/
I noticed that when I installed a desktop that the network manager icon on the taskbar doesn't work. I believe that is because by default Ubuntu 20.04 uses netplan and in turn that defaults to network. That can be changed in /etc/netplan/50-cloud-init.yaml I think. I haven't tested it with a desktop as I decided to go with a non-GUI setup but I did switch to NetworkManager on the server as I'm more familiar with it.