Dynamic proxy_pass in nginx to another pod in Kubernetes

Question

I\'m trying to create an nginx proxy that forwards requests to / to http://. I first tried the following:

Answer 1

I resolved this by coredns docker ： my nginx and coredns are all deploy on host

step1: config Corefile in Corefile maybe you should change k8s master config refer: https://coredns.io/plugins/kubernetes/

sudo mkdir /etc/coredns; sudo tee /etc/coredns/Corefile   <<-'EOF' .:53 {
    log
    errors
    health
    kubernetes cluster.local in-addr.arpa ip6.arpa {
       endpoint http://172.31.88.71:8080
       pods insecure
       upstream
       fallthrough in-addr.arpa ip6.arpa
       ttl 30
    }
    forward . /etc/resolv.conf
    cache 30
    loop
    reload
    loadbalance } EOF

step2:config docker and then start it

tee coreos.sh   <<-'EOF'
 docker run --restart=always  -idt --name coredns \
 -v /etc/coredns/Corefile:/etc/coredns/Corefile \
 -v /home/ec2-user/.kube/config:/etc/coredns/kubeconfig \
 -p 53:53/udp \
 coredns/coredns:1.6.9 \
 -conf /etc/coredns/Corefile
EOF

step3: config nginx and then reload

resolver 127.0.0.1 valid=60s ipv6=off;

Answer 2

After much research and trial and error I managed to solve this. First I changed the pod specification to:

spec:
  containers:
    - name: nginx
      image: "nginx:1.10.0"
      ports:
        - containerPort: 8080
          name: "external"
          protocol: "TCP"
    - name: dnsmasq
      image: "janeczku/go-dnsmasq:release-1.0.5"
      args:
        - --listen
        - "127.0.0.1:53"
        - --default-resolver
        - --append-search-domains
        - --hostsfile=/etc/hosts
        - --verbose

then I also had to disable the ipv6 for the resolver in nginx:

location ~ ^/(.+)$ {
        resolver 127.0.0.1:53 ipv6=off;
        set $backend "http://$1:80";
        proxy_pass $backend;
}

Then it works as expected!