I was just looking at my Raspberry Pi Zero and realized that I’m running stuff that I don’t need! Why am I wasting precious CPU cycles on the likes of cups (printer software), aplay and pulseaudio (sound software), Xorg, and lxpanel (the desktop GUI)? I’ll let avahi-daemon live for now. I think the DNS updates that it provides are helpful on other systems when I run something like “arp -a”.
root@zero-basement:~# top
top - 08:03:37 up 7 min, 3 users, load average: 0.90, 0.68, 0.49
Tasks: 106 total, 1 running, 105 sleeping, 0 stopped, 0 zombie
%Cpu(s): 3.7 us, 4.3 sy, 0.0 ni, 91.7 id, 0.3 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 477.6 total, 135.0 free, 139.6 used, 203.0 buff/cache
MiB Swap: 100.0 total, 100.0 free, 0.0 used. 282.6 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
358 root 20 0 41124 9308 7620 S 24.2 1.9 0:01.10 cups-browsed
1330 root 20 0 91192 5476 4816 S 3.5 1.1 0:00.11 aplay
643 pi 9 -11 357180 8160 7044 S 2.3 1.7 0:05.16 pulseaudio
243 avahi 20 0 5912 2972 2616 S 1.9 0.6 0:02.06 avahi-daemon
248 root 20 0 36920 7924 6756 S 1.9 1.6 0:00.31 cupsd
616 pi 20 0 409312 28940 23024 S 0.6 5.9 0:11.53 lxpanel
9 root 20 0 0 0 0 S 0.3 0.0 0:02.05 ksoftirqd/0
...
Turn off the Sound Card on Raspberry Pi
Let’s get rid of sound, since this Raspberry is just a Zero that hosts a temperature probe in the basement. Create a file using vi or any text editor and save it in “/etc/modprobe.d/alsa-blacklist.conf”. The entire contents of the file should look like this:
blacklist snd_bcm2835
Save the file and reboot the machine. This does just what it looks like. It “blacklists” the module loader from installing the hardware drivers for the sound chip. This is also useful if you’re planning on installing a third-party sound HAT, like the HiFiBerry AMP2. Now, we just need to pull the software, but what’s the command? I dunno’ Let’s do a little digging:
root@zero-basement:~# apt search aplay | grep installed WARNING: apt does not have a stable CLI interface. Use with caution in scripts. alsa-utils/oldstable,now 1.1.8-2+rpt1 armhf [installed] root@zero-basement:~#
A-ha! Now, let’s remove that!
root@zero-basement:~# apt remove alsa-utils Reading package lists... Done Building dependency tree Reading state information... Done The following packages were automatically installed and are no longer required: libfftw3-single3 libsamplerate0 triggerhappy Use 'apt autoremove' to remove them. The following packages will be REMOVED: alsa-utils raspi-config 0 upgraded, 0 newly installed, 2 to remove and 12 not upgraded. After this operation, 2,213 kB disk space will be freed. Do you want to continue? [Y/n]
Uh-oh! Double-check that! This is going to remove “raspi-config” No! I like that program! I’m answering “N”. Let’s move on. Honestly, the reason aplay and PulseAudio were running was that the Raspberry GUI was running and there was a process that was offering screen reading to the visually impaired audience. Now that the GUI is gone, the process stopped.
Remove the GUI Desktop on Raspberry Pi
This is a big one! I’m running headless (no monitor or keyboard) and I only ever ssh in to this Raspberry, so I’m going to remove all the GUI software AND CUPS in one swell foop! There are actually two commands to run. The first one does what we want. The second one removes all the dependencies. Some software depends on lots of other software to be installed. The autoremove command removes all the extra stuff, all those extra dependencies, that you won’t be using anymore. (Caveat Emptor: if you plan on running VLC remote desktop, don’t remove the x11 stuff! You’re gonna need it.)
sudo apt-get remove --auto-remove --purge 'libx11-.*' sudo apt-get autoremove --purge
Run the first command, answer “Y” and let ‘er rip! When it’s done, run the second command and answer “Y” and let that run too. You can actually run the second command again. The system might realize there were some secondary dependencies that could be removed as well. Try it a third time? You never know…
I think we’re good for now. Let’s run “top” again:
top - 09:31:12 up 1:06, 2 users, load average: 0.08, 0.15, 0.38
Tasks: 87 total, 1 running, 86 sleeping, 0 stopped, 0 zombie
%Cpu(s): 2.0 us, 2.0 sy, 0.0 ni, 96.1 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
MiB Mem : 477.6 total, 59.2 free, 81.9 used, 336.5 buff/cache
MiB Swap: 100.0 total, 89.2 free, 10.8 used. 339.3 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6768 root 20 0 10292 3000 2476 R 1.3 0.6 0:00.53 top
541 root 20 0 101764 37968 8692 S 1.0 7.8 2:02.99 salt-minion
249 avahi 20 0 5908 2920 2572 S 0.7 0.6 0:16.09 avahi-daemon
772 root 20 0 12188 5856 5040 S 0.3 1.2 0:03.66 sshd
3534 root 20 0 0 0 0 I 0.3 0.0 0:03.36 kworker/u2:1-brcmf_wq/mmc1:0001:1
6766 root 20 0 0 0 0 I 0.3 0.0 0:00.25 kworker/0:3-events
1 root 20 0 34784 8080 6200 S 0.0 1.7 1:48.78 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:00.02 kthreadd
That’s better! “salt-minion” is a program that I use for configuration management. The rest looks good!
