``traefik`` is a popular reverse-proxy aimed at containerized systems. As such, many may wish to integrate ``Mailu`` into a system which already uses ``traefik`` as its sole ingress/reverse-proxy.
As the ``mailu/front`` container uses ``nginx`` not only for ``HTTP`` forwarding, but also for the mail-protocols like ``SMTP``, ``IMAP``, etc, we need to keep this container around even when using another ``HTTP`` reverse-proxy. Furthermore, ``traefik`` is neither able to forward non-HTTP, nor can it easily forward HTTPS-to-HTTPS. This, however, means 3 things:
- ``mailu/front`` needs to listen internally on ``HTTP`` rather than ``HTTPS``
- ``mailu/front`` is not exposed to the outside world on ``HTTP``
- ``mailu/front`` still needs ``SSL`` certificates (here, we assume ``letsencrypt``) for a well-behaved mail service
This makes the setup with ``traefik`` a bit harder: ``traefik`` saves its certificates in a proprietary ``JSON`` file, which is not readable by the ``nginx`` in the ``front``-container. To solve this, your ``acme.json`` needs to be exposed to the host or a ``docker-volume``. It will then be read by a script in another container, which will dump the certificates as ``PEM`` files, making them readable for ``nginx``. The `front` container will make sure to reload `nginx` whenever these certificates change.
To set this up, first set ``TLS_FLAVOR=mail`` in your ``.env``. This tells ``mailu/front`` not to try to request certificates using ``letsencrypt``, but to read provided certificates, and use them only for mail-protocols, not for ``HTTP``.
Next, in your ``docker-compose.yml``, comment out the ``port`` lines of the ``front`` section for port ``…:80`` and ``…:440``. Add the respective traefik labels for your domain/configuration, like
..code-block:: yaml
labels:
- "traefik.enable=true"
- "traefik.port=80"
- "traefik.frontend.rule=Host:$TRAEFIK_DOMAIN"
**Please don’t forget to add ``TRAEFIK_DOMAIN=[...]`` TO YOUR ``.env``**
If your ``traefik`` is configured to automatically request certificates from ``letsencrypt``, then you’ll have a certificate for ``mail.your.doma.in`` now. However, ``mail.your.doma.in`` might only be the location where you want the ``Mailu`` web-interfaces to live — your mail should be sent/received from ``your.doma.in``, and this is the ``DOMAIN`` in your ``.env``?
To support that use-case, ``traefik`` can request ``SANs`` for your domain. Lets add something like
..code-block:: toml
[acme]
[[acme.domains]]
main = "your.doma.in" # this is the same as $TRAEFIK_DOMAIN!
sans = ["mail.your.doma.in", "webmail.your.doma.in", "smtp.your.doma.in"]
to your ``traefik.toml``. You might need to clear your ``acme.json``, if a certificate for one of these domains already exists.
For the last part, you’re still a bit on your own. You need some solution which dumps the certificates in ``acme.json``, so you can include them in the ``mailu/front`` container. One such example is `traefik-certdumper <https://github.com/Nebukadneza/traefik-certdumper>`, which has been adapted for use in Mailu. You can add it to your ``docker-compose.yml`` like:
..code-block:: yaml
certdumper:
restart: always
image: nebukadneza/traefik-certdumper:latest
environment:
# Make sure this is the same as the main=-domain in traefik.toml
# !!! Also don’t forget to add "TRAEFIK_DOMAIN=[...]" to your .env!
- DOMAIN=$TRAEFIK_DOMAIN
volumes:
- "/data/traefik:/traefik"
- "$ROOT/certs:/output"
assuming you have ``volume-mounted`` your ``acme.json`` put to ``/data/traefik`` on your host. The dumper will then write out ``/data/traefik/ssl/your.doma.in.crt`` and ``/data/traefik/ssl/your.doma.in.key`` whenever ``acme.json`` is updated. Yay! Now let’s mount this to our ``front`` container like:
..code-block:: yaml
volumes:
- "$ROOT/certs:/certs" # Mount both certs directory (for dhparams.pem) and your domains key
Dario Ernst
6 years ago