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The following guide deploys the Minimus MySQL image together with custom certificates generated with OpenSSL to help you get started. Run the code to try it for yourself.

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Components

  • MySQL image: MySQL container configured with --require_secure_transport=ON for client authentication.
  • Dynamic certificate generation via OpenSSL:
    • certgen.sh script: Generates a custom CA, server, and client certificates using OpenSSL.
    • minidebug image: A Minimus dev toolkit that provides a shell, OpenSSL, and other utilities used to generate the certificates.

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What this guide demonstrates

  • TLS handshake validation
  • Server/client certificate trust
  • Basic auth and MySQL operations
  • Image compatibility

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Directory Structure

.
├── certgen.sh             # Certificate generation script
├── create-certs.yml       # Compose file to run certgen container
└── docker-compose.yml     # Compose file to run MySQLDB

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Deploy MySQL with TLS certificates

1

Save certgen.sh

Save the following script to a file named certgen.sh. The script is used to generate the TLS certificates and store them in a certs folder on the host. It sets UID 1000 as the owner of the certificate files to match the default user of the MariaDB process inside the container.
certgen.sh
#!/bin/sh
# Company: Minimus

set -e
cd /certs

echo "[INFO] Generating OpenSSL config..."
cat > openssl.cnf <<EOF
[req]
distinguished_name = req_distinguished_name
prompt = no

[req_distinguished_name]
CN = mysql

[v3_req]
keyUsage = keyEncipherment, dataEncipherment
extendedKeyUsage = serverAuth
subjectAltName = @alt_names

[v3_client]
keyUsage = digitalSignature
extendedKeyUsage = clientAuth
subjectAltName = @alt_names

[v3_ca]
subjectKeyIdentifier = hash
authorityKeyIdentifier = keyid:always,issuer
basicConstraints = critical, CA:true
keyUsage = critical, keyCertSign, cRLSign

[alt_names]
DNS.1 = mysql
DNS.2 = localhost
IP.1 = 172.0.0.1
IP.2 = 192.168.40.0
IP.3 = 192.168.40.2
IP.4 = 192.168.40.3

EOF

echo "[INFO] Creating CA certificate..."
openssl genrsa -out ca-key.pem 2048
openssl req -x509 -new -nodes -key ca-key.pem -sha256 -days 365 \
  -out ca.pem -subj "/CN=MySQL Test CA" \
  -extensions v3_ca -config openssl.cnf

echo "[INFO] Creating server certificate..."
openssl genrsa -out server-key.pem 2048
openssl req -new -key server-key.pem -out server.csr \
  -config openssl.cnf -extensions v3_req
openssl x509 -req -in server.csr -CA ca.pem -CAkey ca-key.pem -CAcreateserial \
  -out server-cert.pem -days 365 -sha256 \
  -extfile openssl.cnf -extensions v3_req

echo "[INFO] Creating client certificate..."
openssl genrsa -out client-key.pem 2048
openssl req -new -key client-key.pem -out client.csr -subj "/CN=root"
openssl x509 -req -in client.csr -CA ca.pem -CAkey ca-key.pem -CAcreateserial \
  -out client-cert.pem -days 365 -sha256 \
  -extfile openssl.cnf -extensions v3_client

# Permissions
chmod 644 *.pem
chown -R 1000:1000 /certs/*.pem || echo "[WARN] chown failed (non-root?)"

echo "[SUCCESS] Certificates generated for MySQL."
2

Save create-certs.yml

Save the following YAML file to run with Docker Compose. It uses the Minimus minidebug image to generate the certificates with the certgen.shshell script. Minidebug is a Minimus dev toolkit that provides a shell, OpenSSL, and other utilities.The certificates will be persisted in the certs volume on the host.
create-certs.yml
services:
  certgen:
    image: reg.mini.dev/minidebug:latest
    container_name: MySQL_certgen
    volumes:
    - ./certs:/certs
    - ./certgen.sh:/certgen.sh:ro
    entrypoint:
    - /bin/sh
    - /certgen.sh
    network_mode: none
3

Generate certificates

Run the following to generate the certificates:
docker compose -f create-certs.yml up

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TLS certificates

The script certgen.sh generates the following self-signed certificates:
  • Self-signed CA certificate (ca.pem )
  • Server certificates (server-cert.pem, server-key.pem, server.csr )
  • Client certificates for testuser (client.csr , client.pem, client-cert.pem ,client-key.pem)
Certificate permissions are adjusted to support non-root containers. We will mount thses certificates into the MySQL container.
4

Save Docker Compose script

Save the following Docker Compose script to a file named docker-compose.yml. This script sets up the MySQL service with a healthcheck, mounts a volume with the certificates, maps port 3306, and connects the container to a custom network:
docker-compose.yml
services:
  mysql:
    image: reg.mini.dev/mysql:latest
    container_name: mysql-1
    environment:
      MYSQL_ROOT_PASSWORD: rootpass
      MYSQL_DATABASE: testdb
      MYSQL_USER: testuser
      MYSQL_PASSWORD: testpass
    volumes:
      - ./certs:/certs:ro
    ports:
    - 3306:3306
    healthcheck:
      test:
      - CMD
      - mysqladmin
      - ping
      - -ptestpass
      interval: 5s
      retries: 10
    command:
    - --ssl-ca=/certs/ca.pem
    - --ssl-cert=/certs/server-cert.pem
    - --ssl-key=/certs/server-key.pem
    - --require_secure_transport=ON
    - --skip-name-resolve
5

Run MySQL

Start the MySQL container:
docker compose -f docker-compose.yml up -d
6

Run tests

Following are a few commands you can try out:
  1. Connect to the database: 
    mysql -h 127.0.0.1 -P 3306 -u root -p \
  --ssl \
  --ssl-ca=./certs/ca.pem \
  --ssl-cert=./certs/client-cert.pem \
  --ssl-key=./certs/client-key.pem
    You should get a response from the server asking to input the password. If you used the compose file from this guide as is, the password is rootpass.
  2. Create a test database (for example my_new_db): 
    CREATE DATABASE my_new_db;
  3. List all databases: 
    SHOW DATABASES;
  4. Show server version: 
    SELECT version();
  5. Check that TLS is active: 
    SHOW VARIABLES LIKE 'tls_version';
SHOW STATUS LIKE 'Ssl_version';
SHOW STATUS LIKE 'Ssl_cipher';
SHOW VARIABLES LIKE 'ssl_%';
    Some server options and system variables were recently deprecated, including --ssl, --skip-ssl, and --admin-ssl server options, and the have_ssl and have_openssl system variables. Learn more