With docker-scripts we can have one or more Wordpress containers, and each container can serve one or more sites, as shown in the diagram:

Since all these sites use the ports 80 and 443, we need a reverse HTTP proxy in order to forward each request to the corresponding container that serves that site/domain. The docker-script container wsproxy plays this role, using Apache virtual domains. Not only that, but wsproxy also gets automatically a free LetsEncrypt SSL certificate for each domain/site that it manages, and also redirects automatically all HTTP requests to HTTPS.

All the containers of docker-scripts are placed on the same local network, and wsproxy knows how to access the container of each domain that it manages. So, only the wsproxy container needs to get the ports 80/443 forwarded from the hosts. The Wordpress containers get their requests from wsproxy through the docker-scripts local network, so they don't need to expose the ports 80/443 to the host or to the outside world.

Each Wordpress container in turn uses Apache virtual domains to be able to serve several (more than one) sites/domains.

Each Wordpress site needs also a database, and all of them use the docker-scripts container mariadb, which they access through the local network of docker-scripts.

1. Install docker:

   curl -fsSL https://get.docker.com -o get-docker.sh
   sudo sh get-docker.sh
   

2. Install docker-scripts:

   apt install m4 make
   git clone https://gitlab.com/docker-scripts/ds /opt/docker-scripts/ds
   cd /opt/docker-scripts/ds/
   make install
   

3. Install Webserver Proxy:

   ds pull wsproxy
   ds init wsproxy @wsproxy
   cd /var/ds/wsproxy/
   vim settings.sh
   ds make
   

4. Install MariaDB:

   ds pull mariadb
   ds init mariadb @mariadb
   cd /var/ds/mariadb/
   vim settings.sh
   ds make
   

1. Install a wordpress container:

   ds pull wordpress
   ds init wordpress @wordpress1
   cd /var/ds/wordpress1/
   vim settings.sh
   ds make
   

2. initialize and Install a Wordpress site:

   cd /var/ds/wordpress1/
   ds site
   ds site init site1.example.org
   ls
   ls site1.example.org
   ls apache2/sites-enabled/
   cat apache2/sites-enabled/site1.example.org.conf
   ls ../wsproxy/sites-enabled/
   cat ../wsproxy/sites-enabled/site1.example.org.conf
   

   Initializing a site with ds site init <domain> not only creates a directory for this site, but also creates the necessary VirtualHost configurations for it on the containers wsproxy and wordpress1. It also gets a free SSL certificate from LetsEncrypt for this site/domain.

   After initializing the site, we can customize its settings.sh and then install wordpress in it:

   vim site1.example.org/settings.sh
   ds site install site1.example.org
   ls site1.example.org/
   

   Now you can open in browser https://site1.example.org and login as admin.

3. Install another site on the same container:

   cd /var/ds/wordpress1/
   ds site init site2.example.org
   ls
   ls site2.example.org
   ls apache2/sites-enabled/
   ls ../wsproxy/sites-enabled/
   

   vim site2.example.org/settings.sh
   ds site install site2.example.org
   ls site2.example.org/
   

4. Install a second container:

   ds init wordpress @wordpress2
   cd /var/ds/wordpress2/
   vim settings.sh
   ds make
   

5. Install a site on the second container:

   ds site init site3.example.org
   vim site3.example.org/settings.sh
   ds site install site3.example.org
   ls site3.example.org/
   

1. Backup site3:

   ds backup
   ds backup site3.example.org
   ls -lh backup/
   

2. Let's delete site3 and then try to restore it from the backup:

   ds site del site3.example.org
   ls
   ls apache2/sites-enabled/
   

   Before restoring, we have to initialize it:

   ds site init site3.example.org
   ls site3.example.org/
   ds restore
   ds restore site3.example.org \
       backup/wordpress-site3.example.org-*.tgz
   ls site3.example.org/
   

3. Clone a site with ds clone:

   ds site clone
   ds site clone site3.example.org site4.example.org
   

   Cloning a site to another one actually initializes the new site, then makes a backup on the source site and restores it on the target site, and finally fixes the options siteurl and home of the new site.

   Cloning a site might be useful when you want to try something new on the site, for example a new plugin or some configuration. Instead of applying it directly to the site, you may want to test it first on a clone.

4. Using wp-cli:

   ds wp
   ds wp site3.example.org
   ds wp site3.example.org option
   ds wp site3.example.org option list
   ds wp site3.example.org option get siteurl
   ds wp site3.example.org option get home
   

5. Working inside the container:

   ds shell
   ls
   cd site3.example.org
   wp
   wp option get siteurl
   wp option get home
   

As we have seen, we can install multiple sites in a single Wordpress container, but we can also install a single site for each Wordpress container. Which one is better?

It depends.

When we consolidate multiple sites in a single Wordpress container we use less resources (RAM and disk space) then installing each site on its own container.

However if one of these sites is compromised (for example you install a plugin with a security hole) it can potentially compromise the other sites that are on the same container.

If each site is on its own container, they are better encapsulated from each-other.