Database Containerization

Containers are basic execution environments that are sandboxed and contained within sandboxed portions of an operating system. They are very useful for developing, testing and even deploying databases. See containers for details.

Pros and Cons

Pros

Containers are lightweight and easy to spin up and down.
Containers are easy to share and distribute.
Containers are easy to version and track.
Containers make it easier to reset the state of a database.
Easy to segregate databases from each other.

Cons

Containers are not as performant as native databases
- Especially in I/O performance, a crucial performance metric for databases.
Container databases are harder to backup and restore without spinning down first.
Accessing logs is harder with container runtimes.

Running MySQL in Docker

You can run various SQL based databases in containers. In this example the MySQL container is run using Docker.

docker run \
    --publish 3306:3306 \
    --env MYSQL_ROOT_PASSWORD='root' \
    --name my-mysql \
    --detach \
    mysql

publish or p specifies the port mapping, from the host port outside the container to the expected ports within the container.
name or n specifies the name to refer to the container as
env or e specifies environment variables to be accessible within the container
- For MySQL you need to specify the password situation:
  - Either MYSQL_ROOT_PASSWORD=SomePassword or MYSQL_ALLOW_EMPTY_PASSWORD
detach or d specifies that the container should run detached, as in not piping into the shell, running in background
mysql [name] the final specifier is the name of the container image to download, in this case mysql

Running MongoDB in Docker

Here [MongoDB] is run in a Docker container.

docker run \
    --publish 27017:27017
    --name some-mongo
    --detach \
    mongo

p specifies the port mapping, from the host port outside the container to the expected ports within the container.
name specifies the name to refer to the container as
d specifies that the container should run detached, as in not piping into the shell, running in background
mongo [name] the final specifier is the name of the container image to download