[BUG] HostRegExp not working with subdomain in K3D Cluster

[freakadunse]

What did you do

• How was the cluster created?

  • sudo k3d cluster create --agents 2 --agents-memory 4096Mi --volume /etc/ssl/certs:/etc/ssl/certs -p "80:80@loadbalancer" -p "443:443@loadbalancer"`

• What did you do afterwards?
  None

What did you expect to happen

we are currently containerizing legacy applications to kubernetes to free some resources.
Stage and Prod are baremetal clusters, development environment is created with k3d docker clusters.

The subdomain HostRegExp is working fine with stage and prod, development is not working and i don't have an idea.
I have created a yaml with a nginx test server which should be reachable with http://contracts./ for you to retest/reproduce my issue.

Which OS & Architecture

• Debian 11

Which version of k3d

k3d version v.5.3.0

Which version of docker

20.10.12

Example YAML

apiVersion: v1
kind: Namespace
metadata:
  name: nginx-test
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  namespace: nginx-test
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: nginx:1.14.2
          ports:
            - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx
  namespace: nginx-test
spec:
  selector:
    app: nginx
  ports:
    - name: nginx
      port: 80
      targetPort: 80
---
apiVersion: traefik.containo.us/v1alpha1
kind: IngressRoute
metadata:
  name: ingressroutetls
  namespace: nginx-test
spec:
  entryPoints:
    - websecure
    - web
  routes:
    - match: "HostRegexp(`{subdomain:contracts}.*`)"
      kind: Rule
      services:
        - name: nginx
          port: 80

If i remove the HostRegExp it is working fine, but i'd rather have this service available with the subdomain.
It's also working when i switch the HostRegExp with Host(<FQDN>).

Any idea what i might do wrong? Chance is, it might be a layer 8 error .. i just can't see it :D

thanks!

BR
Pascal

[iwilltry42]

Hi @freakadunse , thanks for starting this discussion!
As this is not directly related to k3d but more to Traefik, I moved it to a general discussion.
In a quick test, just removing the . in the regexp made it work for me 🤔
Not sure if it's exactly the same functionality then on traefik's end, but at least this ensures that it's most likely not a k3d issue 🤔