MariaDB in Docker: Maintenance and Updates

Running MariaDB in Docker is easy, but maintaining it properly requires some knowledge. Here's how to update, backup, and troubleshoot your MariaDB containers.

Why MariaDB?

MariaDB is the community-developed fork of MySQL, offering:

• Open source - Truly free, no licensing concerns
• MySQL compatible - Drop-in replacement
• Active development - Regular security updates
• Performance - Often faster than MySQL
• Docker ready - Official images available

Basic Docker Setup

docker-compose.yml

services:
  mariadb:
    image: mariadb:10.11
    container_name: mariadb
    restart: unless-stopped
    environment:
      - MYSQL_ROOT_PASSWORD=${DB_ROOT_PASSWORD}
      - MYSQL_DATABASE=myapp
      - MYSQL_USER=myuser
      - MYSQL_PASSWORD=${DB_PASSWORD}
    volumes:
      - mariadb_data:/var/lib/mysql
    ports:
      - "3306:3306"

volumes:
  mariadb_data:

Backup Strategies

Method 1: mysqldump

Best for small/medium databases:

# Backup
docker exec mariadb mysqldump -u root -p${DB_ROOT_PASSWORD} --all-databases > backup.sql

# Single database
docker exec mariadb mysqldump -u root -p${DB_ROOT_PASSWORD} mydatabase > mydatabase.sql

Method 2: Volume Backup

Best for large databases:

# Stop container first!
docker stop mariadb

# Backup volume
docker run --rm \
  -v mariadb_data:/data:ro \
  -v $(pwd):/backup \
  alpine tar czf /backup/mariadb-data.tar.gz /data

# Restart
docker start mariadb

Method 3: Automated Backups

docker-compose.yml

services:
  mariadb-backup:
    image: databack/mysql-backup
    container_name: mariadb-backup
    environment:
      - DB_SERVER=mariadb
      - DB_USER=root
      - DB_PASS=${DB_ROOT_PASSWORD}
      - DB_DUMP_TARGET=/backup
      - DB_DUMP_FREQ=1440  # Daily
      - DB_DUMP_BEGIN=0300 # 3 AM
    volumes:
      - ./backups:/backup
    depends_on:
      - mariadb

Updating MariaDB

Minor Updates (10.11.x)

Safe and usually painless:

# Update image
docker compose pull mariadb

# Recreate container
docker compose up -d mariadb

Major Updates (10.x → 11.x)

Always backup first!

# 1. Backup everything
docker exec mariadb mysqldump -u root -p --all-databases > pre-upgrade.sql

# 2. Stop container
docker compose stop mariadb

# 3. Update compose file version
# image: mariadb:10.11  →  image: mariadb:11.2

# 4. Start new version
docker compose up -d mariadb

# 5. Run upgrade script
docker exec mariadb mysql_upgrade -u root -p

mysql_upgrade Explained

After major version upgrades, run:

docker exec -it mariadb mysql_upgrade -u root -p

This:

• Upgrades system tables
• Checks all tables
• Fixes compatibility issues

Restoring from Backup

From mysqldump

# Restore all databases
docker exec -i mariadb mysql -u root -p${DB_ROOT_PASSWORD} < backup.sql

# Restore single database
docker exec -i mariadb mysql -u root -p${DB_ROOT_PASSWORD} mydatabase < mydatabase.sql

From Volume Backup

# Stop container
docker stop mariadb

# Remove old volume
docker volume rm mariadb_data

# Restore volume
docker run --rm \
  -v mariadb_data:/data \
  -v $(pwd):/backup \
  alpine tar xzf /backup/mariadb-data.tar.gz -C /

# Start container
docker start mariadb

Performance Tuning

Basic Tuning

custom.cnf

[mysqld]
innodb_buffer_pool_size = 1G
innodb_log_file_size = 256M
innodb_flush_log_at_trx_commit = 2
max_connections = 200
query_cache_size = 0
query_cache_type = 0

Mount config file:

volumes:
  - ./custom.cnf:/etc/mysql/conf.d/custom.cnf:ro

Monitoring

# Check status
docker exec mariadb mysqladmin -u root -p status

# Show processes
docker exec mariadb mysqladmin -u root -p processlist

# Interactive monitor
docker exec -it mariadb mysql -u root -p -e "SHOW FULL PROCESSLIST;"

Common Issues

Container Won't Start

# Check logs
docker logs mariadb

# Common: permissions issue
docker run --rm -v mariadb_data:/data alpine chown -R 999:999 /data

Can't Connect

# Check if running
docker ps | grep mariadb

# Test connection
docker exec mariadb mysqladmin -u root -p ping

Forgot Root Password

# Stop container
docker stop mariadb

# Start with skip-grant-tables
docker run -it --rm \
  -v mariadb_data:/var/lib/mysql \
  mariadb:10.11 \
  --skip-grant-tables --user=mysql

# In another terminal, reset password
docker exec -it container_id mysql
# mysql> FLUSH PRIVILEGES;
# mysql> ALTER USER 'root'@'localhost' IDENTIFIED BY 'newpassword';

Health Checks

Add to compose:

services:
  mariadb:
    healthcheck:
      test: ["CMD", "mysqladmin", "ping", "-h", "localhost", "-u", "root", "-p${DB_ROOT_PASSWORD}"]
      interval: 30s
      timeout: 10s
      retries: 3

Learn More

• MariaDB Update Guide
• Nextcloud Database Setup

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