If you want to redirect one domain to another, but your registrar does not provide a solution for that, you can spin up a small NGINX container to do just that.

Docker

Docker-Compose file

Default

The docker-compose.yml should look like this.

version: "3"
services:
  nginx-redirect:
    image: nginx
    container_name: nginx-redirect
    volumes:
      - ./config/default.conf:/etc/nginx/conf.d/default.conf
    networks:
      - net
    restart: unless-stopped
    ports:
      - 80:80

With Traefik

If you use traefik, you can take this as an example, but you will probably need to change the network name. Mine is called net.

version: "3"
services:
  nginx-redirect:
    image: nginx
    container_name: nginx-redirect
    volumes:
      - ./config/default.conf:/etc/nginx/conf.d/default.conf
    networks:
      - net
    restart: unless-stopped
    labels:
      - "traefik.enable=true"
      - "traefik.http.routers.nginx-redirect.rule=Host(`blog.jrehkemper.de`)"
      - "traefik.http.routers.nginx-redirect.entrypoints=https"
      - "traefik.http.routers.nginx-redirect.tls=true"
      - "traefik.http.routers.nginx-redirect.tls.certresolver=production"
      - "traefik.docker.network=net"

networks:
  net:
    name: net
    external: true

NGINX-Config

Now we need to configure the nginx-server to redirect requests. In the compose file we already mounted the file ./config/default.conf into the container. Now we need to create the default.conf file.

server {
  listen 80;
  server_name blog.jrehkemper.de;
  return 301 $scheme://jrehkemper.de$request_uri;
}

In this example I will redirect from blog.jrehkemper.de to jrehkemper.de, but you can use every other domain as well.

$scheme contains if the request was http or https.
$request_uri contains the path behind the domain.
You can omit them if you want to.

Start the Container

Finally we need to start the container.

[tux@server]$ docker-compose up -d

Now the redirect should work as expected.

Kubernetes

Of course the same works with Kubernetes. Therefor we need to create a manifest like the.

---
apiVersion: v1
kind: Namespace
metadata:
  name: blog-redirect

---
apiVersion: v1
kind: ConfigMap
metadata:
  name: nginx-config
  namespace: blog-redirect
data:
  nginx.conf: |-
    server {
      listen 80;
      server_name blog.jrehkemper.de;
      return 301 $scheme://jrehkemper.de;
    }

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: redirect-nginx
  namespace: blog-redirect
  labels:
    app: nginx
spec:
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
        - name: nginx
          image: nginx:latest
          volumeMounts:
            - name: config
              mountPath: "/etc/nginx/conf.d"
      volumes:
        - name: config
          configMap:
            name: nginx-config
            items:
              - key: "nginx.conf"
                path: "nginx.conf"

---
apiVersion: v1
kind: Service
metadata:
  name: nginx-service
  namespace: blog-redirect
  labels:
    app: nginx
spec:
  ports:
  - port: 80
  selector:
    app: nginx

---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: nginx-ingress
  namespace: blog-redirect
spec:
  rules:
    - host: blog.jrehkemper.de
      http:
        paths:
          - pathType: Prefix
            path: "/"
            backend:
              service:
                name: nginx-service
                port:
                  number: 80