Traefik, Frontend, Backend, ZEO container example

Traefik, Frontend, Backend, ZEO container example#

This example is a simple setup with one or more backend instances accessing a ZEO server, with data persisted in a Docker volume.

In this example, Traefik Proxy routes requests to the frontend and the backend.

Setup#

Create an empty project directory named traefik-volto-plone-zeo.

mkdir traefik-volto-plone-zeo

Change into your project directory.

cd traefik-volto-plone-zeo

Service configuration with Docker Compose#

Create a docker-compose.yml file with the following content. Traefik reads its routing configuration from the labels of the frontend and backend services, so this example doesn't need a separate proxy configuration file.

services:

  traefik:
    image: traefik:${STACK_TRAEFIK_TAG:?Set STACK_TRAEFIK_TAG}
    ports:
      - "80:80"
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock:ro
    command:
      - --providers.docker
      - --providers.docker.exposedbydefault=false
      - --entrypoints.http.address=:80
      - --accesslog

  frontend:
    image: plone/plone-frontend:${STACK_FRONTEND_TAG:?Set STACK_FRONTEND_TAG}
    environment:
      RAZZLE_INTERNAL_API_PATH: http://backend:8080/Plone
    depends_on:
      - backend
    labels:
      - traefik.enable=true
      # Service
      - traefik.http.services.svc-frontend.loadbalancer.server.port=3000
      # Router
      - traefik.http.routers.rt-frontend.rule=Host(`plone.localhost`)
      - traefik.http.routers.rt-frontend.entrypoints=http
      - traefik.http.routers.rt-frontend.service=svc-frontend

  backend:
    image: plone/plone-backend:${STACK_BACKEND_TAG:?Set STACK_BACKEND_TAG}
    environment:
      SITE: Plone
      ZEO_ADDRESS: db:8100
      ZEO_SHARED_BLOB_DIR: on   # otherwise the backend will create its own blob storage
    volumes:
      - vol-site-data:/data     # the backend and database need access to the same volume
    depends_on:
      - db
    labels:
      - traefik.enable=true
      # Service
      - traefik.http.services.svc-backend.loadbalancer.server.port=8080
      # Middleware: Virtual Host Monster rewrite for /++api++/
      - "traefik.http.middlewares.mw-backend-vhm-api.replacepathregex.regex=^/\\+\\+api\\+\\+($$|/.*)"
      - "traefik.http.middlewares.mw-backend-vhm-api.replacepathregex.replacement=/VirtualHostBase/http/plone.localhost/Plone/++api++/VirtualHostRoot$$1"
      # Router
      - traefik.http.routers.rt-backend-api.rule=Host(`plone.localhost`) && PathPrefix(`/++api++`)
      - traefik.http.routers.rt-backend-api.entrypoints=http
      - traefik.http.routers.rt-backend-api.service=svc-backend
      - traefik.http.routers.rt-backend-api.middlewares=mw-backend-vhm-api

  db:
    image: plone/plone-zeo:${STACK_ZEO_TAG:?Set STACK_ZEO_TAG}
    restart: always
    volumes:
      - vol-site-data:/data

volumes:
  vol-site-data: {}

Note

Use http://plone.localhost/ to access the website. If plone.localhost doesn't resolve on your computer, add it to your /etc/hosts file, pointing to the IP address of the Docker host.

Environment variables#

The docker-compose.yml file reads the tags of its images from the following environment variables. All of them are required, and docker compose stops with an error if one of them is missing.

Variable

Description

Default value

Example

STACK_FRONTEND_TAG

Tag (version) of the image for the frontend

19

STACK_BACKEND_TAG

Tag (version) of the image for the backend

6.2

STACK_ZEO_TAG

Tag (version) of the image for the ZEO server

6

STACK_TRAEFIK_TAG

Tag (version) of the image for Traefik

v3.7

Create a .env file in your project directory with your values. Docker Compose reads it automatically when you run docker compose from that directory.

STACK_FRONTEND_TAG=19
STACK_BACKEND_TAG=6.2
STACK_ZEO_TAG=6
STACK_TRAEFIK_TAG=v3.7

Build the project#

Start the stack with docker compose.

docker compose up -d

This pulls the needed images and starts Plone.

Access Plone in a browser#

After startup, go to http://plone.localhost/ and you should see the site.

Increase the number of backends#

To use two containers for the backend, run docker compose with --scale.

docker compose up -d --scale backend=2

Traefik distributes the requests to the backend among both containers.

Shutdown and cleanup#

The command docker compose down removes the containers and default network, but preserves the Plone database.

The command docker compose down --volumes removes the containers, default network, and the Plone database.

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