Kubernetes: Route incoming traffic to specific Pod

Question

I want to deploy many Pods in Google Kubernetes Engine and then establish a TCP connection to each specific Pod by Subdomain like pod-name-or-label.mydomain.com or path routing like protocol://mydomain.com:7878/pod-name-or-label.

I have looked in different directions like Istio or nginx-ingress, but that seems to me to be too complicated.

Is not there a simple solution for that?

A standalone `Pod` is not the way to go for this and is most certainly an anti-pattern. Your best bet is to move up a couple abstractions to the `Deployment` resource, and then you can deploy multiple copies of your `Pod` with some variation in labels between them to dictate ingress and routing. — erstaples, Nov 08 '18 at 17:51
Pod is not something to work with in production , define a deployment and expose it using nodePort , then use session persistence with kube-proxy set to serve from local node only. — Ijaz Ahmad, Nov 08 '18 at 18:18
This [article](https://cloud.google.com/kubernetes-engine/docs/how-to/exposing-apps#top_of_page) shows how to create Kubernetes Services in a Google Kubernetes Engine cluster And how to create a service of [Nodeport](https://cloud.google.com/kubernetes-engine/docs/how-to/exposing-apps#creating_a_service_of_type_nodeport). — Milad Tabrizi, Nov 08 '18 at 22:58

score 2 · Answer 1 · answered Nov 10 '18 at 18:29

For Istio, You can use VirtualService to control the routing rules to the target subset with defining by DestinationRules.

The DestinationRule will route to the target Pods by the specified label pods.

The request flow will like to:

+--------------------+
|                    |
|    Istio Gateway   |
|                    |
|                    |
+---------+----------+
          |traffic incoming
          |
+---------v----------+
|                    |
|   VirtualService   |
|                    |
|                    |
+---------+----------+
          |route to subset by the routing rules
          v

+--------------------+
|                    |
|  DestinationRules  |
|                    |
|                    |
+---------+----------+
          |route traffic to target pods
          v

+--------------------+
|                    |
|                    |
|       Pods         |
|                    |
+--------------------+

so as @ericstaples said you should create different Deployments with different pod labels to achieve separating traffic to the target pods, Example:

create a deployment with pod label: t1
create a subset in DestinationRule: select t1 label pod as subset s1
control your traffic in VirtualService that route to s1 subset
s1 route to the target pods

also for expose Gateway, you can use ClusterIP or NodePort like ** Kubernetes** other service did, see more of Istio Traffic.

There are some references maybe it's helpful:

https://istio.io/docs/concepts/traffic-management/

https://istio.io/docs/tasks/traffic-management/request-routing/

score 1 · Answer 2 · answered Aug 19 '20 at 12:39

This question is bit old, but in current Kubernetes versions you can do it easly using Nginx Ingress.

If you want to reach your application from outside the cluster you need to expose it using Services. Easiest way is to use Service with selectors when you put the same selector in Deployment/Pod and Service. Example below:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: test1
spec:
  replicas: 1
  selector:
    matchLabels:
      key: test1
  template:
    metadata:
      labels:
        key: test1
    spec:
      containers:
      - name: hello1
        image: gcr.io/google-samples/hello-app:1.0
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: test1
spec:
  selector:
    key: test1
  ports:
    - port: 80
      targetPort: 8080

Path routing will be configured in Ingress. As on the example below:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: my.pod.svc 
    http:
      paths:
      - path: /pod
        backend:
          serviceName: my-pod
          servicePort: 80
  - host: nginx.test.svc
    http:
      paths:
      - path: /abc
        backend:
          serviceName: nginx1
          servicePort: 80

For more details you can check this thread.

score 0 · Answer 3 · answered Nov 12 '18 at 16:03

Now i have that solution with istio installed on the cluster:

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: echo-gateway
spec:
  selector:
    istio: ingressgateway # use istio default controller
  servers:
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "dev.sample.com"

With that gateway i can apply that Deployment, Service, VirtualService

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-echo-1000-deployment
  labels:
    echoservice: echo-1000
spec:
  replicas: 1
  selector:
    matchLabels:
      echoservice: echo-1000
  template:
    metadata:
      labels:
        echoservice: echo-1000
    spec:
      containers:
      - image: gcr.io/google-containers/echoserver:1.10
        imagePullPolicy: IfNotPresent
        name: my-echo-run-container
        ports:
        - containerPort: 8080
          protocol: TCP

---

apiVersion: v1
kind: Service
metadata:
  name: my-echo-1000-service
  labels:
    echoservice: echo-1000
spec:
  ports:
  - port: 8080
    name: http
  selector:
    echoservice: echo-1000

---

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: my-echo-1000-vservice
spec:
  hosts:
  - "dev.sample.com"
  gateways:
  - echo-gateway
  http:
  - match:
    - uri:
        exact: /echo-1000
    route:
    - destination:
        host: my-echo-1000-service
        port:
          number: 8080

Get the LoadbalancerIP from istio-ingressgateway and make an entry in /etc/hosts for dev.sample.com

Now i can get the echoserver in specific Pod with http://dev.sample.com/echo-1000

Is that a good solution or is there a better one?

Kubernetes: Route incoming traffic to specific Pod

3 Answers3

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