raspberry pi

Everything I know about Kubernetes I learned from a cluster of Raspberry Pis

I realized I haven't posted about my DrupalCon Seattle 2019 session titled Everything I know about Kubernetes I learned from a cluster of Raspberry Pis, so I thought I'd remedy that. First, here's a video of the recorded session:

The original Raspberry Pi Dramble Cluster
The original Pi Dramble 6-node cluster, running the LAMP stack.

The best way to keep your cool running a Raspberry Pi 4

From home temperature monitoring to a Kubernetes cluster hosting a live Drupal website, I have a lot of experience running Raspberry Pis. I've used every model through the years, and am currently using a mix of A+, 2 model B, and 4 model B Pis.

Stack of Raspberry Pi model B and B+ 2 3 4

The 3 model B+ was the first generation that had me concerned more about cooling (the CPU gets hot!), and the Pi 4's slightly increased performance made that problem even more apparent, as most of my heavier projects resulted in CPU throttling. I've written about how the Raspberry Pi 4 needs a fan, and more recently how it might not.

Upgrade the Raspberry Pi 4's firmware / bootloader for better thermals

In October, the Raspberry Pi Foundation released an updated bootloader/firmware for the Raspberry Pi 4 which dramatically reduces power consumption and overall temperatures on the Pi 4 by setting the USB controller and CPU into a more power-friendly mode.

I wanted to post here the instructions for checking the current version, and upgrading, because I have a large number of Pis to upgrade over time, and I needed a quick reference. For more details, check out the Raspberry Pi Documentation page Raspberry Pi 4 boot EEPROM.

Checking if the current bootloader is up to date

Upgrade system packages and install the rpi-eeprom utility:

$ sudo apt update
$ sudo apt -y full-upgrade
$ sudo apt install -y rpi-eeprom

Check if an update is required:

$ sudo rpi-eeprom-update

If you see a difference in the output, you can restart to update to the newer version. If everything's the same, you're already on the latest version.

The Raspberry Pi 4 might not need a fan anymore

tl;dr: After the fall 2019 firmware/bootloader update, the Raspberry Pi 4 can run without throttling inside a case—but only just barely. On the other extreme, the ICE Tower by S2Pi lives up to its name.

Raspberry Pi 4 cooling options including ICE tower cooling fan and a case mod fan
Three options for keeping the Pi 4 cozy: unmodified Pi 4 case, modded case with fan, and the ICE Tower.

A few months ago, I was excited to work on upgrading some of my Raspberry Pi projects to the Raspberry Pi 4; but I found that for the first time, it was necessary to use a fan to actively cool the Pi if used in a case.

Two recent developments prompted me to re-test the Raspberry Pi 4's thermal properties:

Raspberry Pi microSD follow-up, SD Association fools me twice?

 ____________________________________________
/ Fool me once, shame on you. Fool me twice, \
\ prepare to die. (Klingon Proverb)          /
 --------------------------------------------
        \   ^__^
         \  (oo)\_______
            (__)\       )\/\
                ||----w |
                ||     ||

(Excerpt from Ansible for DevOps, chapter 12.)

The fallout from this year's microSD card performance comparison has turned into quite a rabbit hole; first I found that new 'A1' and 'A2' classifications were supposed to offer better performance than the not-Application-Performance-class-rated cards I have been testing. Then I found that A2 rated cards offer no better performance for the Raspberry Pi—in fact they didn't even perform half as well as they were supposed to, for 4K random reads and writes, on any hardware I have in my possession.

A2-class microSD cards offer no better performance for the Raspberry Pi

Update: See follow-up post about A1 vs A2 performance, Raspberry Pi microSD follow-up, SD Association fools me twice?.

After I published my 2019 Raspberry Pi microSD card performance comparison, I received a lot of feedback about newer 'A2' Application Performance class microSD cards, and how they could produce even better performance for a Raspberry Pi.

A2 Performance Class SanDisk and Lexar microSD cards next to older Samsung and SanDisk cards
None of these cards are fakes; grainy halftone printing is visible because I shot this with a macro lens.

The Raspberry Pi 4 needs a fan, here's why and how you can add one

The Raspberry Pi Foundation's Pi 4 announcement blog post touted the Pi 4 as providing "PC-like level of performance for most users". The Foundation even offers a Raspberry Pi 4 Desktop Kit.

The desktop kit includes the official Raspberry Pi 4 case, which is an enclosed plastic box with nothing in the way of ventilation.

I have been using Pis for various projects since their introduction in 2012, and for many models, including the tiny Pi Zero and various A+ revisions, you didn't even need a fan or heatsink to avoid CPU throttling. And thermal images or point measurements using an IR thermometer usually showed the SoC putting out the most heat. As long as there was at least a little space for natural convection (that is, with no fan), you could do almost anything with a Pi and not have to worry about heat.

Raspberry Pi microSD card performance comparison - 2019

Note: I also posted a separate review of some A2 'Application Performance' class cards, see this post: A2-class microSD cards offer no better performance for the Raspberry Pi.

Raspberry Pi Noobs SD card adapter with a number of Samsung and other microSD cards

As a part-time tinkerer and full-time developer, I have been fascinated by single board computers (SBCs) since the first Raspberry Pi was introduced almost a decade ago. I have owned and used every generation of Raspberry Pi, in addition to most of the popular competitors. You can search my site for tons of articles on these experiences.

Basement electrical work - electric dryer and clothes washer wiring

The Geerling household is preparing for the largest home project to date; and while my wife and I have decided to spend a bit extra to have a contractor do the work for the actual kitchen reno, we are still doing what we can to maintain a functional household during the extensive refurbishment of our original kitchen, dining, and laundry area to make it a lot more amenable to our family lifestyle (our current layout is difficult with three kids and two kitchen peninsulas!).

'Phase 1', as I'm calling it, was the electrical work to support moving our electric dryer, clothes washer, and maybe even dishwasher to the basement during the course of the project. I installed a 75A sub-panel in the basement last year (it was my last major home improvement project before the surgery), and it's time to start putting the extra slots in it to good use!

As with most of my projects nowadays, I recorded the entire event as a time-lapse with a Raspberry Pi Zero, using my Raspberry Pi Time-Lapse App. And here it is, for you to enjoy!

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