Multisite configuration with Docker

:warning: While multisite is supported in the Discourse application, this is an advanced sysadmin setup. If you don’t know what you’re doing, do not set up multisite. The Discourse team is unable to provide multisite configuration support.

If you wish to host multiple domains on a singled Docker setup, you’ll need a multisite configuration. Here are the basic building blocks for one.

Understand hooks

Multisite is a fairly advanced topic. Before attempting a multisite build, spend some time to learn about them.

Discourse templates use pups; its rules are simple and powerful.

Each rule you run may define a hook:

run:
  exec:
    cd: some/path
    hook: my_hook
    cmd:
      - echo 1

Later on in your container you can insert rules before or after a hook:

hooks:
  before_my_hook:
    - exec: echo "I ran before"
  after_my_hook:
     - exec: echo "I ran after"

So in the example above you will see output like the following:

I ran before
1
I ran after

You can read through the templates in /var/discourse/templates to see what hooks you have available.

Amend your standalone container to provision the second site tenant

Replace the entire hooks section with:

hooks:
  after_postgres:
     - exec: sudo -u postgres createdb b_discourse || exit 0
     - exec:
          stdin: |
            grant all privileges on database b_discourse to discourse;
          cmd: sudo -u postgres psql b_discourse
          raise_on_fail: false

     - exec: /bin/bash -c 'sudo -u postgres psql b_discourse <<< "alter schema public owner to discourse;"'
     - exec: /bin/bash -c 'sudo -u postgres psql b_discourse <<< "create extension if not exists hstore;"'
     - exec: /bin/bash -c 'sudo -u postgres psql b_discourse <<< "create extension if not exists pg_trgm;"'

  after_code:
    - exec:
        cd: $home/plugins
        cmd:
          - mkdir -p plugins
          - git clone https://github.com/discourse/docker_manager.git
  before_bundle_exec:
    - file:
        path: $home/config/multisite.yml
        contents: |
         secondsite:
           adapter: postgresql
           database: b_discourse
           pool: 25
           timeout: 5000
           db_id: 2
           host_names:
             - b.discourse.example.com

  after_bundle_exec:
    - exec: cd /var/www/discourse && sudo -E -u discourse bundle exec rake multisite:migrate

There are 3 hooks in play:

  1. after_postgres ensures that after postgres is installed an additional db called b_discourse is created with the appropriate permissions.

  2. before_bundle_exec, ensures docker_manager is in place and that the multisite.yml file is in place (which defines where to find the databases)

  3. after_bundle_exec, runs the custom db migration task rake multisite:migrate this ensures all the dbs are up to date.

Note on configuration

The above sample can be split into data container / app container if needed. Just run the after_postgres hook in the data container and the rest in web container.

The above sample can be extended to provision even more DBs. To do so, provision more DBs by duplicating the create db etc calls, and make sure you add additional sites in multisite.yml.

Make sure you amend the host_names node in multisite.yml to match the actual host name you wish to host.

Also, if you plan to run HTTPS, you will need a proxy in front of the site to handle it as the built in letsencrypt functionality will not work in a multisite scenario.

56 Likes
How does multisite.yml look?
How to create 1000 subcategories in a scalable way?
Multiple Forums in a Single Installation
Pros and cons of multiple standalone containers vs one for multiple Discourse installs?
Multiple Discourses, multiple containers, one server
Success - New Multisite Install on Dedicated server using ServerPilot, Nginx and Apache
Multisite Installation
Will I need to start over with multisite configuration from standalone version?
Installation wizard not appearing in multisite installs
Multiple Discourse Installs - Single Server
Starting a second Discourse forum on the same VPS
Pros and cons of a multisite installation
Disabling/restricting user search
Sandbox and test discourse on host?
Multisite installation with seperated smtp emails
How do you set up multiple discourse forums on the same server?
How to move from standalone container to separate web and data containers
Need proper documentation for multisite discourse with docker
Discourse multisite installation help with digitalocean
Three sites in one setup
Can I log into multiple instances of discourse simultaneously?
Multisite viability - 2 read-only and 1 active
Multiple discourse instances in a single server
Install Discourse on Plesk / Ubuntu 14 without Docker
Totally Walled-Off Groups
Discourse for 3 different Countrys
Second discourse instance on the same server
I want to host hundreds of instances of Discourse
Best approach for test and production instance of discourse
How do I set category tracking level defaults historically
Two standalone instances on one server?
Can we change lets encrypt script?
How to move from standalone container to separate web and data containers
Stable branch assets won't compile
Using a launcher built docker image in docker-compose
Setting up Let’s Encrypt with Multiple Domains
Integration with .NET MVC application for a SaaS platform
Setting up Let’s Encrypt with Multiple Domains
Multisite for small collection of sites for a family?
How to move from standalone container to separate web and data containers
Contabo experience with Plesk, Webmin or other server-admin setup?
Need help with multisite configuration
Docker image update: Redis 6 and 25% smaller image size
Hosting Plan Suggestion for 500 Concurrent Online Users
How can Admin login while Read-only mode is enabled on multisite?
Avatar, Site Logos, and Cert Errors
Secure cookie configuration
App.yml shared volumes for a two website setup
Feature proposal: Customizations based on primary group membership, a.k.a. tenancy 'lite'
How to move from standalone container to separate web and data containers
Can I have two domains pointing towards the same IP address without redirect?
How to move from standalone container to separate web and data containers
Help me setup many websites on one VPS
Multiple container setup problems
Installing on Kubernetes
Add path to cookie
Multitenat Dockerize Discourse
PAID Require Discourse expert for extreme customization
How to set redis DB ID in Docker container?
Recover to one site from multisite
Running other websites on the same machine as Discourse
Pull request for Wikis?
Stable branch assets won't compile
How can I host more than 1 Discourse forum on 1 VPS?
Micro Forums: how many could I create?
Multiple discourse installation on single droplet
ActiveRecord::StatementInvalid: PG::UndefinedColumn: ERROR: column categories.search_priority does not exist
Multisite installation ... in subdirectories?
Are there other workarounds to not having category moderation such as multiple instances of the board?
Multiple discourse instances in a single server
Running other websites on the same machine as Discourse
Multisite Config

I’ve verified this guide is correct and made some copy edits for readability and structure.

10 Likes

I intend to update this guide with instructions to use Let’s Encrypt without an external reverse proxy as suggested here.

3 Likes