====== Docker + MariaDB Setup on Ubuntu 22.04 ======

This guide documents the steps used to set up Docker CE and a MariaDB instance on a minimal VPS (1 vCPU, 1 GB RAM) running Ubuntu 22.04. It's designed to be simple and portable — ideal for DevOps-style projects, dashboards, and APIs that may later be migrated to a cloud platform like Azure Container Apps.

===== 💡 Why this approach? =====

The goal is to:

  * Make the environment **reproducible** and easy to redeploy
  * Avoid configuring software manually on the system (e.g., `apt install mariadb-server`)
  * Use **Docker volumes** to persist data independently of the container
  * Support **CI/CD, local testing**, and future **migration to the cloud**

This method works well even on small servers, and can easily be integrated into Terraform, Ansible, or CI workflows later on.

---

===== 🐳 Script: Install Docker CE on Ubuntu =====

<code bash>
#!/bin/bash
# install-docker-ce.sh — Installs Docker Engine on Ubuntu 22.04+

set -e

sudo apt-get update
sudo apt-get install -y \
    ca-certificates \
    curl \
    gnupg \
    lsb-release

# Add Docker’s official GPG key
sudo install -m 0755 -d /etc/apt/keyrings
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | \
    sudo gpg --dearmor -o /etc/apt/keyrings/docker.gpg
sudo chmod a+r /etc/apt/keyrings/docker.gpg

# Add the repository
echo \
  "deb [arch=$(dpkg --print-architecture) \
  signed-by=/etc/apt/keyrings/docker.gpg] \
  https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) stable" | \
  sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

# Install Docker Engine
sudo apt-get update
sudo apt-get install -y docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin

# Enable Docker service
sudo systemctl enable docker
sudo systemctl start docker

echo "Docker installed successfully!"
</code>

---

===== 🐬 docker-compose.yml for MariaDB =====

This Compose file defines a MariaDB service with a persistent volume. The `restart: unless-stopped` line ensures it comes back after a reboot, unless stopped manually.

<code yaml>
services:
  mariadb:
    image: mariadb:latest
    container_name: mariadb
    restart: unless-stopped
    environment:
      - MYSQL_ROOT_PASSWORD=your_root_pass
    ports:
      - "3306:3306"
    volumes:
      - mariadb_data:/var/lib/mysql

volumes:
  mariadb_data:
    external: true
</code>

---

===== 📦 Notes on Volume Migration and Backup =====

This setup stores your MariaDB data inside a Docker-managed volume (not inside the container). You can move this volume to another server like this:

1. Find the volume's path on the source server:

<code bash>
docker inspect mariadb | grep Source
</code>

2. Stop the container, then tar the volume contents:

<code bash>
docker stop mariadb
sudo tar -czvf mariadb_data.tar.gz /var/lib/docker/volumes/your_volume_name/_data
</code>

3. Copy the `.tar.gz` to the new server:

<code bash>
scp mariadb_data.tar.gz user@newserver:~
</code>

4. Extract into a Docker volume path (on the new server):

<code bash>
docker volume create mariadb_data
sudo tar -xzvf mariadb_data.tar.gz -C /var/lib/docker/volumes/mariadb_data/_data
</code>

5. Now `docker compose up -d` with the same `docker-compose.yml`, and your DB will be live.

---

Example for copying the volume:

<code bash>
#!/bin/bash
set -e

VOLUME_ID="4042cf30bc39026f2b18ef4f2fcd2893470efba3637f5e18f1a762856debba0d"
VOLUME_PATH="/var/lib/docker/volumes/${VOLUME_ID}/_data"
ARCHIVE_NAME="mariadb_volume_backup.tar.gz"
DEST_HOST="facundo@10.241.79.111"
DEST_PATH="/tmp"

echo "==> Stopping any container using the volume..."
docker ps -q --filter volume="$VOLUME_ID" | while read cid; do
    docker stop "$cid"
done

echo "==> Creating archive from volume data..."
sudo tar -czf "$ARCHIVE_NAME" -C "$VOLUME_PATH" .

echo "==> Copying archive to destination server..."
scp "$ARCHIVE_NAME" "$DEST_HOST:$DEST_PATH"

echo "==> Done. You can now restore it on serv1 using the corresponding import steps."
</code>

then restore in the destination server...

<code bash>
#!/bin/bash
set -e

VOLUME_ID="mariadb_restored_volume"
ARCHIVE_PATH="/tmp/mariadb_volume_backup.tar.gz"
VOLUME_PATH="/var/lib/docker/volumes/${VOLUME_ID}/_data"

echo "==> Creating target volume..."
docker volume create "$VOLUME_ID"

echo "==> Extracting data into new volume..."
sudo tar -xzf "$ARCHIVE_PATH" -C "$VOLUME_PATH"

echo "==> Fixing permissions..."
sudo chown -R 999:999 "$VOLUME_PATH"  # 999 is default mysql UID/GID in official image

echo "==> Starting MariaDB container..."
docker run -d \
  --name mariadb \
  -v "${VOLUME_ID}:/var/lib/mysql" \
  -e MYSQL_ROOT_PASSWORD=your_root_pass \
  -p 3306:3306 \
  mariadb:latest

echo "==> Done! MariaDB should be up with old data."
</code>
===== ✅ Final Thoughts =====

This method allows you to:

  * Maintain a clean server environment
  * Version control your infra and DB layout via YAML
  * Restore or replicate the setup with minimal effort
  * Migrate between servers or to the cloud with ease

You can add your Flask API and Dashboard apps into the same Compose file, or deploy them independently. This is the foundation of a production-ready system built from tiny building blocks.

Enjoy!