Connecting to MariaDB in Docker: Fixing "Access Denied" with Docker Compose
- MySQL/MariaDB: This error indicates that you're trying to connect to a MySQL or MariaDB database running in a Docker container using the
root
user from your local machine (localhost
), but the connection is being rejected due to incorrect credentials or configuration. - Docker: Docker is a containerization platform that allows you to package applications with their dependencies into standardized units called containers.
- Docker Compose: Docker Compose is a tool for defining and running multi-container applications with Docker. It helps you easily configure services, networks, and volumes for your application.
- External Volume: An external volume is a directory on your host machine that you map to a directory inside the Docker container. This allows you to persist data generated by the container, even if the container is recreated.
Potential Causes and Solutions:
-
Incorrect Root Password:
-
External Volume Interfering with Initialization:
-
Conflicting Credentials in External Volume:
-
Incorrect Connection Method:
Additional Tips:
- Consider creating a non-root user with appropriate permissions for your application instead of using
root
. - Store passwords securely and avoid hardcoding them in configuration files.
version: "3"
services:
mariadb:
image: mariadb:10.4.8
environment:
MYSQL_ROOT_PASSWORD: your_strong_password
volumes:
# Add volumes for persistent data if needed (optional)
- my-data-volume:/var/lib/mysql
Handling External Volume and Initialization:
Option A: Create a new, empty volume for initialization:
version: "3"
services:
mariadb:
image: mariadb:10.4.8
volumes:
- new-data-volume:/var/lib/mysql # Empty volume for initialization
Option B: Temporarily remove volume mount during initialization:
version: "3"
services:
mariadb:
image: mariadb:10.4.8
# Comment out volume mount during initialization
# volumes:
# - my-data-volume:/var/lib/mysql
# Run initialization command (optional)
command: mysqld --initialize-insecure
# Uncomment volume mount after initialization
# volumes:
# - my-data-volume:/var/lib/mysql
Connecting to the Container:
Using docker exec
:
docker exec -it mariadb_container mysql -u root -p your_strong_password
Using a separate client application:
mysql -h <container_ip_address> -u root -p your_strong_password
Replace placeholders like:
your_strong_password
: Your actual strong password for the root user.my-data-volume
: The name of your external volume.new-data-volume
: Name for the new volume used during initialization (if used).mariadb_container
: The name of your MariaDB container.<container_ip_address>
: The IP address of your MariaDB container (usedocker inspect mariadb_container
to find it).
- This is a more secure approach compared to using the
root
user. - Define a dedicated user with specific permissions for your application in the container's initialization script or by connecting to the container and running MariaDB commands.
Example (using docker-compose.yml
):
version: "3"
services:
mariadb:
image: mariadb:10.4.8
environment:
MYSQL_ROOT_PASSWORD: your_strong_password # For initialization
volumes:
- my-data-volume:/var/lib/mysql
command: mysqld --initialize-insecure # Initialize with insecure mode
mysql -u root -p your_strong_password <<-EOF
CREATE USER my_user@localhost IDENTIFIED BY 'my_user_password';
GRANT ALL PRIVILEGES ON my_database.* TO my_user@localhost;
FLUSH PRIVILEGES;
EOF
- Replace
my_user
,my_user_password
, andmy_database
with your desired values. - This example creates a user
my_user
with a passwordmy_user_password
and grants them all privileges on themy_database
database.
Using a Secrets Management Tool:
- Consider using a secrets management tool like HashiCorp Vault or AWS Secrets Manager to store sensitive information like the root password securely and retrieve it dynamically when starting the container.
- This improves security by keeping passwords out of your code or configuration files.
Environment Variables for Non-Root User Credentials:
- Define environment variables in your
docker-compose.yml
to store the non-root user credentials:
version: "3"
services:
mariadb:
image: mariadb:10.4.8
environment:
MYSQL_ROOT_PASSWORD: your_strong_password # For initialization
MYSQL_USER: my_user
MYSQL_PASSWORD: my_user_password
volumes:
- my-data-volume:/var/lib/mysql
command: mysqld --initialize-insecure # Initialize with insecure mode
- Connect to the container using these credentials:
mysql -h <container_ip_address> -u $MYSQL_USER -p $MYSQL_PASSWORD
Important Considerations:
- Choose the method that best suits your security requirements and application needs.
- For production environments, using a non-root user and a secrets management tool is highly recommended.
- Always prioritize strong password practices and avoid hardcoding them in configuration files.
mysql docker docker-compose