745c2af792
Example: a pod like the below should
proxy port 53 TCP and UDP to the main DNS service.
```
apiVersion: v1
kind: Pod
metadata:
name: localhost-dns-proxy
spec:
containers:
- name: proxy-udp
image: gcr.io/google_containers/proxy-to-service:v1
args: [ "udp", "53", "kube-dns.default" ]
ports:
- name: udp
protocol: UDP
containerPort: 53
hostPort: 53
- name: proxy-tcp
image: gcr.io/google_containers/proxy-to-service:v1
args: [ "tcp", "53", "kube-dns.default" ]
ports:
- name: tcp
protocol: TCP
containerPort: 53
hostPort: 53
```
49 lines
1.7 KiB
Markdown
49 lines
1.7 KiB
Markdown
# Proxy a pod port or host port to a kubernetes Service
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While Kubernetes provides the ability to map Services to ports on each node,
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those ports are in a special range set aside for allocations. This means you
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can not not simply choose to expose a Service on port 80 on your nodes. You
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also can not choose to expose it on some nodes but not others. These things
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will be fixed in the future, but until then, here is a stop-gap measure you can
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use.
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The container image `gcr.io/google_containers/proxy-to-service:v1` is a very
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small container that will do port-forwarding for you. You can use it to
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forward a pod port or a host port to a service. Pods can choose any port or
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host port, and are not limited in the same way Services are.
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For example, suppose you want to forward a node's port 53 (DNS) to your
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cluster's DNS service. The following pod would do the trick:
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```
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apiVersion: v1
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kind: Pod
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metadata:
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name: dns-proxy
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spec:
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containers:
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- name: proxy-udp
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image: gcr.io/google_containers/proxy-to-service:v1
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args: [ "udp", "53", "kube-dns.default" ]
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ports:
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- name: udp
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protocol: UDP
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containerPort: 53
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hostPort: 53
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- name: proxy-tcp
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image: gcr.io/google_containers/proxy-to-service:v1
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args: [ "tcp", "53", "kube-dns.default" ]
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ports:
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- name: tcp
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protocol: TCP
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containerPort: 53
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hostPort: 53
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```
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This creates a pod with two containers (one for TCP, one for UDP). Each
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container receives traffic on a port (53 here) and forwards that traffic to the
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kube-dns service. You can run this on as many or as few nodes as you want.
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[]()
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