The goal of this project is to setup Mongo DB on a Pi Zero. I am fairly new to the Pi Zero and this is mainly for documenting steps and lessons learned.

Initial Installation

Using the Raspberry Pi Imager v1.5:

Select Raspberry Pi OS Lite (32-bit)
Write to 32 GB micro SD card

N**ote: Ubuntu does not work for the Raspberry Pi Zero W

Initial Power-up

login: u:pi, p:raspberry
sudo raspi-config to setup wifi and change default password
reboot when prompted

Note: Within raspi-config, I set Localisation Options (5) -> WLAN Country (L4), System Options (1) -> Wireless LAN (S1) and Password (S3)

Install and Upgrade all components

sudo apt update
sudo apt upgrade

Install Mongo DB

sudo apt install mongodb

Note: From what I’ve read, Mongo DB appears to be deprecating the 32-version. Ubuntu has a path forward for the latest Mongo DB, but since Pi Zero is based on Raspberry Pi 1 (Arm6) and Ubuntu no longer supports it, we are limited to the version provided with Raspberry Pi OS

Create RAM Disk

For my purpose, I want to use a ram disk for Mongo DB.. At this time I don’t really want to retain any data… perhaps in the future

# create the folder
sudo mkdir /mnt/ramdisk

# create the ramdisk with 100 MB capacity
sudo mount -t tmpfs -o rw,size=100M tmpfs /mnt/ramdisk


# setup the ramdisk at boot
sudo nano /etc/fstab

# add the following line to the end
tmpfs  /mnt/ramdisk  tmpfs  rw,size=100M  0   0

#Ctrl-O to Save
#Strl-X to Exit

Configure and Start Mongo DB

Now we need to point Mongo DB at the RAM Disk

sudo nano /etc/mongodb.conf

# change the dbpath
dbpath=/mnt/ramdisk

# Ctrl+O to save
# Ctrl+X to exit


sudo systemctl enable mongodb
sudo systemctl start mongodb
sudo systemctl status mongodb

# reboot
sudo reboot

# verify ramdisk
ls /mnt/ramdisk

# verify auto-start of mongo
sudo systemctl status mongodb

Note: The version available uses mongodb rather than mongod like is current.. I was tripped up by this when trying to start the service

Testing Mongo DB

To verify that it is all working, lets use the mongo cli to add and query data

# query databases
db

# select the test database
use db

db.createCollection('projects');

# it seems that either single or double quotes are supported
db.projects.insert({id:'apple', name:'Apple'});
db.projects.insert({id:'banana', name:'Banana'});

# query newly created data
db.projects.find();

quit()

I connected via SSH to get the console output directly…

pi@raspberrypi:~ $ mongo
MongoDB shell version: 2.4.14
connecting to: test
Server has startup warnings:
Mon Jan 18 05:07:17.214 [initandlisten]
Mon Jan 18 05:07:17.214 [initandlisten] ** NOTE: This is a 32 bit MongoDB binary.
Mon Jan 18 05:07:17.215 [initandlisten] **       32 bit builds are limited to less than 2GB of data (or less with --journal).
Mon Jan 18 05:07:17.215 [initandlisten] **       Note that journaling defaults to off for 32 bit and is currently off.
Mon Jan 18 05:07:17.215 [initandlisten] **       See http://dochub.mongodb.org/core/32bit
Mon Jan 18 05:07:17.216 [initandlisten]
> use test
switched to db test
> db.projects.find();
{ "_id" : ObjectId("60051c0dd548855d5de48b06"), "id" : "apple", "name" : "Apple" }
{ "_id" : ObjectId("60051c39d548855d5de48b07"), "id" : "banana", "name" : "Banana" }
>

…and we’re done! I am unsure of the present limitations of this version of Mongo DB, but it is intended for some local test applications only.

Mongo DB on Raspberry Pi Zero W

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