* Postgres Official Image (based on Debian)
```
docker pull postgres

docker run -rm --name postgresdb-instance \
-p 5432:5432 \
-e POSTGRESQL_USER=<db_user> \
-e POSTGRESQL_PASSWORD=<user_pwd> \
-e POSTGRESQL_DATABASE=<db_name> \
-e POSTGRESQL_ADMIN_PASSWORD=<adm_pwd> \
-e POSTGRESQL_SHARED_BUFFERS=40 \
-d postgres:latest
```

* MariaDB (MySQL) Official Image (based on Debian)
```
docker pull mariadb

docker run -rm --name mariadb-instance \
-p 3306:3306 \
-e MYSQL_ROOT_PASSWORD=<some_pwd> \
-e MYSQL_DATABASE=<db_name> \
-e MYSQL_USER=<user_name> \
-e MYSQL_PASSWORD=<user_pwd> \
-d mariadb:latest

docker run -it --link some-mariadb:mysql \
--rm mariadb \
sh -c 'exec mysql -h"$MYSQL_PORT_3306_TCP_ADDR" -P"$MYSQL_PORT_3306_TCP_PORT" -uroot -p"$MYSQL_ENV_MYSQL_ROOT_PASSWORD"'
```