How do i keep docker environment persistent?

amurleopard

The containers are ephemeral unless given a volume. Volumes make the docker environment persistent.

version: '2'
services:
    wordpress:
    image: wordpress
    ports:
      - 8080:80
    environment:
      WORDPRESS_DB_PASSWORD: example

  mysql:
    image: mariadb
    environment:
      MYSQL_ROOT_PASSWORD: example
    volumes:
      - "./volumes/db:/var/lib/mysql"

Under the volumes section the ./volumes/db maps to /var/lib/mysql. The files needed for the db are stored in volumes directory for persistence. Removing the docker environment and bringing it back up, will be the same as before removing it, keeping all db updates.