Modern Reverse Proxy with Traefik on Docker Swarm

Traefik is a modern load balancer and reverse proxy built for micro services.

We will build 4 WebServices with Traefik, where we will go through the following scenarios:

Hostname Based Routingi (With Path's and Without)
Path Based Routing

Pre-Requisites:

From your DNS Provider add wildcard entries to the Docker Swarm Public IPs:

apps.domain.com -> A Record to each Docker Swarm Node
*.apps.domain.com => apps.doamin.com

This will allow us to create web applications on the fly.

Static Website with Traefik:

Create Traefik Proxy:

docker service create \
--name traefik \
--constraint 'node.role==manager' \
--publish 80:80 \
--publish 443:443 \
--publish 8080:8080 \
--mount type=bind,source=/var/run/docker.sock,target=/var/run/docker.sock \
--network appnet \
traefik:camembert \
--docker --docker.swarmmode  \
--docker.domain=apps.domain.com \
--docker.watch \
--logLevel=DEBUG \
--web

Build a WebService with 2 Endpoints:

Our Website will have:

/
/test/

Our Dockerfile:

Dockerfile

FROM alpine:edge

RUN apk update \
    && apk add lighttpd

ADD htdocs /var/www/localhost/htdocs

CMD ["lighttpd", "-D", "-f", "/etc/lighttpd/lighttpd.conf"]

Our htdocs directory:

find ./htdocs/
./htdocs/
./htdocs/index.html
./htdocs/test
./htdocs/test/index.html

Building and Push the Image to a Registry of your choice:

docker login registry.gitlab.com
docker build -t registry.gitlab.com/<user>/<repo>/lighttpd:test
docker push registry.gitlab.com/<user>/<repo>/lighttpd:test

Create the 1st Service, No Hostname or Path based specified:

The Service will allow us to view / and /test/ paths, and also enable us to use the service name as the subdomain, or the domain specified in the traefik service:

docker service create --name web1 --label 'traefik.port=80'  --network appnet --with-registry-auth registry.gitlab.com/<user>/<repo>/lighttpd:test

Testing the service:

$ curl http://web1.apps.domain.com/
<html>
Root Page
</html>

$ curl http://web2.apps.domain.com/test/
<html>
Test Page
</html>

and

$ curl http://apps.domain.com/test/
<html>
Test Page
</html>

but

$ curl http://foo.apps.domain.com/test/
404 page not found

Create the 2nd Service, Only 1 Path Based Routing:

This service will only allow us to view the /test/ endpoint:

$ docker service create --name website2 --label 'traefik.port=80' --label traefik.frontend.rule="Path: /test/" --network appnet --with-registry-auth registry.gitlab.com/<user>/<repo>/lighttpd:test

Testing the Service:

$ curl http://web1.apps.domain.com/
404 page not found

$ curl http://web2.apps.domain.com/test/
<html>
Test Page
</html>

Hostname Based and Path Based Routing:

$ docker service create \
--name web3 \
--label 'traefik.port=80' \
--label traefik.frontend.rule="Host:apps.domain.com; Path: /test/" \
--network appnet \
--with-registry-auth registry.gitlab.com/rbekker87/docker/lighttpd:u1t-test

Test the / endpoint, which should not work:

$ curl  http://apps.domain.com/
404 page not found

and the /test/ endpoint:

$ curl  http://apps.domain.com/test/
<html>
Test Page
</html>

Also, any other FQDN that is specified will not work as it does not match the traefik.frontend.rule:

$ curl  http://web3.apps.domain.com/
404 page not found

Strictly Hostname Based Routing and not specifying any paths:

$ docker service create \
--name web4 \
--label 'traefik.port=80' \
--label traefik.frontend.rule="Host:apps.domain.com" \
--network appnet \
--with-registry-auth registry.gitlab.com/<user>/<repo>/lighttpd:u1t-test

Testing the Service:

$ curl http://apps.domain.com/
<html>
Root Page
</html>

$ curl http://apps.domain.com/test/
<html>
Test Page
</html>

Anything specified other than that, will result in a 404 Response.