iptables in kuberntes init container does't work

Background:

I'm trying to use goreplay to mirror the traffic to other destination. I found that k8s service is a load balancing on layer 4 which cause the traffic can not be capture by goreplay,So i decide to add a reverse-proxy sidecar inside pod just like istio does.

Here is my pod yaml:

apiVersion: v1
kind: Pod
metadata:
  name: nginx
  namespace: default
  labels:
    app: nginx
spec:
  containers:
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: nginx
    ports:
    - containerPort: 80
      name: http
      protocol: TCP
    resources: {}
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File
  - image: nginx
    imagePullPolicy: IfNotPresent
    name: proxy
    resources:
      limits:
        cpu: "2"
        memory: 1Gi
      requests:
        cpu: 10m
        memory: 40Mi
    terminationMessagePath: /dev/termination-log
    terminationMessagePolicy: File  
    volumeMounts:
      - mountPath: /etc/nginx/conf.d
        name: default   
  initContainers:
    - command: 
      - iptables
      args:
      - -t 
      - nat
      - -A
      - PREROUTING
      - -p
      - tcp
      - --dport
      - "80"
      - -j
      - REDIRECT
      - --to-ports
      - "15001"
      image: soarinferret/iptablesproxy
      imagePullPolicy: IfNotPresent
      name: istio-init
      resources:
        limits:
          cpu: 100m
          memory: 50Mi
        requests:
          cpu: 10m
          memory: 10Mi
      securityContext:
        allowPrivilegeEscalation: false
        capabilities:
          add:
          - NET_ADMIN
          - NET_RAW
          drop:
          - ALL
        privileged: false
        readOnlyRootFilesystem: false
        runAsGroup: 0
        runAsNonRoot: false
        runAsUser: 0
      terminationMessagePath: /dev/termination-log
      terminationMessagePolicy: File        
  dnsPolicy: ClusterFirst
  terminationGracePeriodSeconds: 30
  volumes:
    - configMap:
        defaultMode: 256
        name: default
        optional: false
      name: default
---

apiVersion: v1
kind: Service
metadata:
  name: nginx
  namespace: default
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: nginx
  sessionAffinity: None
  type: ClusterIP
status:
  loadBalancer: {}

--- 

apiVersion: v1
data:
  default.conf: |
    server {
        listen       15001;
        server_name  localhost;
        access_log  /var/log/nginx/host.access.log  main;
        location / {
            root   /usr/share/nginx/html;
            index  index.html index.htm;
        }
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   /usr/share/nginx/html;
        }
    }
kind: ConfigMap
metadata:
  name: default
  namespace: default

I use kubectl port-forward service/nginx 8080:80 and then curl http://localhost:8080,the traffic were sent directly to nginx not my proxy.

WHAT I WANT:

1. A way to let goreplay to capture traffic that load balanced by k8s service.
2. Correct iptables rule to let traffic success route to my proxy sideCar.

Thanks for any help!