Self hosting two instances in one host

Developer help Self-hosting
1 
version: '3.1'

services:

  ghost:
    image: ghost:5-alpine
    restart: always
    ports:
      - 8080:2368
    environment:
      # see https://ghost.org/docs/config/#configuration-options
      database__client: mysql
      database__connection__host: db
      database__connection__user: root
      database__connection__password: example
      database__connection__database: ghost
      # this url value is just an example, and is likely wrong for your environment!
      url: http://localhost:8080
      # contrary to the default mentioned in the linked documentation, this image defaults to NODE_ENV=production (so development mode needs to be explicitly specified if desired)
      #NODE_ENV: development
    volumes:
      - ghost:/var/lib/ghost/content

  db:
    image: mysql:8.0
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: example
    volumes:
      - db:/var/lib/mysql

volumes:
  ghost:
  db:

I created my first instance using the compose file base above, but I want to create another instance other than the first I created. If I run the same compose file, it will overwrite the existing one instead of creating another. So how do I create another instance?

2

You could update your compose file to run two different Ghost containers with different service names.

The second one should run on a different ports besides port 8080 on the host. Your webserver, should have a secon configuration to proxy traffic to the second host in the new port.

You’ll need to map a different volume on the host to /var/lib/content in the second container so that they each have unique content.

The two Ghost containers both use the same MySQL container, each accessing different databases within it.

3

First Instance

version: '3.1'

services:

  ghost:
    image: ghost:5-alpine
    restart: always
    ports:
      - 8080:2368
    environment:
      # see https://ghost.org/docs/config/#configuration-options
      database__client: mysql
      database__connection__host: db
      database__connection__user: root
      database__connection__password: example
      database__connection__database: ghost
      # this url value is just an example, and is likely wrong for your environment!
      url: http://localhost:8080
      # contrary to the default mentioned in the linked documentation, this image defaults to NODE_ENV=production (so development mode needs to be explicitly specified if desired)
      #NODE_ENV: development
    volumes:
      - ghost:/var/lib/ghost/content

  db:
    image: mysql:8.0
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: example
    volumes:
      - db:/var/lib/mysql

volumes:
  ghost:
  db:

Second Instance

version: '3.1'

services:

  secondghost:
    image: ghost:5-alpine
    restart: always
    ports:
      - 8080:2368
    environment:
      # see https://ghost.org/docs/config/#configuration-options
      database__client: mysql
      database__connection__host: db
      database__connection__user: root
      database__connection__password: example
      database__connection__database: secondghost
      # this url value is just an example, and is likely wrong for your environment!
      url: http://localhost:8080
      # contrary to the default mentioned in the linked documentation, this image defaults to NODE_ENV=production (so development mode needs to be explicitly specified if desired)
      #NODE_ENV: development
    volumes:
      - ghost:/var/lib/ghost/content

  db:
    image: mysql:8.0
    restart: always
    environment:
      MYSQL_ROOT_PASSWORD: example
    volumes:
      - db:/var/lib/mysql

volumes:
  ghost:
  db:

So the plain configs above should work for hosting two instances in a one host?

4

I don’t use Docker compose, but it’s my understanding that two Compose files like that won’t work because the service names-- like naming the database service the same thing, will conflict with each other. Also, you’d end up running two copies of MySQL. You can do that, but it seems like a waste of resources to me.

What I suggested above was using a single compose file.

You may want to read the documentation for the compose file format to better understand how it works.