Secrets in Docker without Swarm

Question

I am using Docker, but not Swarm (or any other orchestration) for a project.

Is there a way to leverage Docker Secrets without Swarm?

Answer 1

You can use docker secrets a bit differently using docker-compose without having to use swarm. See this for the official documentation.

Example:

1. Create a simple compose file like so,

version: "3.7"
services:
db:
    image: mariadb:10.5.2
    env_file:
      - ./db.env
    secrets:
      - rootpass
      - dbpass
      - mysqldb
      - mysqluser
    restart: always

2. Now add the following in the end

secrets:
  rootpass:
    file: /tmp/root_pass
  dbpass:
    file: /tmp/db_pass
  mysqldb:
    file: /tmp/mysql_db
  mysqluser:
    file: /tmp/mysql_user

3. Inside those files, keep your password, username, database name etc. in plain text. Then simply deploy the containers docker-compose up -d.

It's similar to how you define volumes and networks in a compose file.

Keep in mind that this isn't true secret implementation. Here's the github PR that added this feature, along with the main file if you're interested.

Answer 2

Regarding the documentation in https://hub.docker.com/_/mariadb?tab=description, your solution can be this:

version: "3.9"
services:
db:
    image: mariadb:10.7
    secrets:
      - rootpass
      - dbpass
      - mysqldb
      - mysqluser
    environment:
      MARIADB_ROOT_PASSWORD_FILE: /run/secrets/rootpass
      MARIADB_DATABASE_FILE: /run/secrets/mysqldb
      MARIADB_USER_FILE: /run/secrets/mysqluser
      MARIADB_PASSWORD_FILE: /run/secrets/dbpass
    restart: unless-stopped
    ports:
      - '3306:3306'
secrets:
  rootpass:
    file: ./cf/root_pass
  dbpass:
    file: ./cf/db_pass
  mysqldb:
    file: ./cf/mysql_db
  mysqluser:
    file: ./cf/mysql_user