Directly serves Roundcube webmail via HTTP and connects to a MySQL database container. The Roundcube sources and the database files are stored on connected volumes.

Roundcube served from PHP-FPM via Nginx using a Postgres DB

See docker-compose-fpm.yaml or docker-compose-fpm-alpine.yaml.

An Nginx webserver serves Roundcube from a PHP-FPM container via CGI and static files from the shared Roundcube sources. A Postgres database container is used to store Roundcube's session and user data. The Roundcube sources and the database files are stored on connected volumes.

Installing Roundcube Plugins

With the latest updates, the Roundcube images contain the Composer binary which is used to install plugins. You can add and activate plugins by executing composer.phar require <package-name> inside a running Roundcube container:

$ docker exec -it roundcubemail composer require johndoh/contextmenu --update-no-dev

If you have mounted the container's volume /var/www/html the plugins installed persist on your host system. Otherwise they need to be (re-)installed every time you update or restart the Roundcube container.

Kubernetes Cluster

The sample kubernetes.yaml file configures a Roundcube installation on a Kubernetes cluster with three individual deployments and services which can be scaled individually:

roundcubedb: Postgres database
roundcubemail: PHP-FPM with Roundcube
roundcubenginx: Nginx service serving HTTP

The setup defines three PersistentVolumeClaims for database and shared temp file storage as well as for sharing the static file of Roundcube with the Nginx pods which finally serve them via HTTP.

This is only an example and needs to be modified and tweaked for productive systems. At least set the ROUNDCUBEMAIL_DEFAULT_HOST and ROUNDCUBEMAIL_SMTP_SERVER and change the values of the roundcubemail-shared-secret Secret.