Estimated time: 20 minutes (+10 if older distro version).

• Preface
• Installing Docker
• Running Database Container
• Setting Up Your Database

Preface

You can find all of the included scripts and commands in this repo:

https://github.com/kmjbyrne/docker-mysql/

Before following any guide on setting up something new, it is always advised to update your host OS packages. This becomes more applicable if you have an older Debian version running on an older Raspberry Pi like model 2. I wrote up this guide using my older model 2+ which was installed in 2016 or so. A number of issues arose with this, particularly package repos going out of date, binaries not being found etc. I had moved house about 5 times and it was mostly sitting in a container during this time, other life aspects took precedence. It happens.

To update OS packages:

sudo apt update
sudo apt upgrade

I have a couple of model 4s as well, for which the installation is much simpler really as the scope of upgrades here was much smaller.

Please note that this particular section only relates to your Pi if it was installed some time ago and is as my board was, not at all maintained.

Docker itself requires an updated version of libseccomp to function correctly.

Following advice from this guide: https://docs.linuxserver.io/faq#libseccomp

I used Option 2. However you can also just reinstall as noted in Option 3. This would be the "best practice" approach but if you have reasons or simply don't want to go through the ringer doing so, Option 2 will suffice (for now).

Installing Docker

Installing Docker is a relatively simple step. Docker would not be as popular if this wasn't the case :)

If you haven't already, update update update!

sudo apt update
sudo apt upgrade

Now install Docker:

sudo apt install docker

You will want to add docker user to own user group, for most users this will be pi. Running this command will prevent the need to run sudo docker ... for every docker command. This gets irritating very fast!

sudo usermod -a -G docker ${USER}

Docker does not automatically spin up containers after a reboot/boot so you will want to also set this to avoid your services going offline and staying so if you reboot (this is inevitable):

sudo systemctl enable docker

Docker Compose is a series of utilities that come in handy when you have docker-compose configurations. If you don't need this, bypass.

To install Docker Compose:

sudo pip3 install docker-compose

At this point, we have completed Checkpoint #1. Hooray!

Running Database Container

The database we will use for this exercise is MariaDB.

MariaDB is very similar to MySQL and for most users, will have the same offerings. There are of course some differences and many folks believe MariaDB to be better of the two in fact. I have in the past, defaulted to MySQL but I see little difference and will likely steer towards MariaDB more and more.

For installation on a Raspberry Pi which uses ARM processor architecture MariaDB as of 2022-01-14 is the better supported between MySQL and MariaDB.

Fun fact: the developers of MariaDB were also of MySQL.

Docker will need to first build a database image from the Docker repo.

The following can be broken down into a docker-compose.yml file but for the sake of keeping this lean, this will be linked as bonus material.

You will want to create a password that is not shared or stored anywhere on the local file system in plaintext.

read -p "Please enter password for root MySQL user: " PASSWORD

Set a DATAPATH variable, what this does is provide the docker container with a local path. This makes sure your database data is persistent! If you don't have a datapath setup, if the container and image is destroyed, as will all the database data!

DATAPATH="/var/mariadb"

Now, let's get that container running!

The following script is essentially telling Docker to run a new container, named db on port 3306.

--restart unless-stopped is signalling to Docker that this container should remain active until manually stopped.

-v is an argument flag for the data volume used for persistence.

-e is an argument flag for environment variables which we will use to provide the MYSQL_ROOT_PASSWORD to allow you to interact with the database server in the next step.

-d is a flag to signal that this container should run in detached mode. Basically running as a daemon. If this argument is not provided, Docker will use the running terminal instance and once you terminate the session, the Docker container will also stop.

Finally, the last positional argument is the name of the Docker image we want to use.

For more info see: https://docs.linuxserver.io/images/docker-mariadb

docker run --name db \
    -p 3306:3306 \
    --restart unless-stopped \
    -v "${DATAPATH}:/var/lib/mysql" \
    -e MYSQL_ROOT_PASSWORD="${PASSWORD}" \
    -d linuxserver/mariadb

Now lets check that the container is running, if you did not see any particular Docker errors we should expect so.

Run:

docker ps

You should see something similar to:

CONTAINER ID        IMAGE                 COMMAND             CREATED             STATUS              PORTS                    NAMES
[containerid]       linuxserver/mariadb   "/init"             2 hours ago         Up 2 hours          0.0.0.0:3306->3306/tcp   db

Where containerid will be equal to whatever ID Docker assigns to your MariaDB container.

This brings us to Checkpoint #2, now we have a running database containerized instance that is exposes port 3306 (default for MySQL).

Setting Up Your Database

The reason this step is optional is due to the fact that some people will have their own specific approach for this. I included this as a quick way to bootstrap your DB and get a non-root user setup. You should not really be using root user for accessing the DB from remote hosts. Security matters even for hobbyists. It not fun to have any of your assets compromised.