Raspberry Pi Power Savings and LED Configuration

One of the latest enhancements to my network-based booting Raspberry Pi cluster involved disabling some of the extra hardware and LED lights to save a bit of power, as well as enhance visual indications during restarts, crashes, etc. I've shared snippets of my /boot/config.txt file and have annotated my reasoning for the settings changes.

# Enable audio (loads snd_bcm2835)
#dtparam=audio=on

##turn on/ off bluetooth
dtoverlay=disable-bt

##turn on/off wifi
dtoverlay=disable-wifi

##disable PWR LED
dtparam=pwr_led_trigger=none
dtparam=pwr_led_activelow=off

##turn off ethernet port LEDs
dtparam=eth_led0=4
dtparam=eth_led1=4

##enable heartbeat activity LED pattern
dtparam=act_led_trigger=heartbeat

If you are using your Raspberry Pi for Kubernetes or as a general purpose server and are using network-based booting, there is rarely a need to have audio, Bluetooth, or WiFI enabled, so why not save a bit of power multiplied by each Raspberry Pi.

The LED-related sections disable the always-on power indicator and Ethernet-related LEDs to also save a little bit more energy, but it also has a secondary purpose. In this configuration, the power and Ethernet LEDs only come on until the Raspberry PI loads the kernel parameters to disable them. The power light will only come back on after the kernel crashed or the system has been shutdown. This creates a helpful "red stop light" and only runs the difficult to see Ethernet-related LEDs for the boot sequence when they are imperative.