kubernetes
/
website
mirror of https://github.com/kubernetes/website.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

Tidy port forward task 

* Reword to follow style guidelines

* Highlight commands as shell code

* Specify minimum version

This metadata alters the behavior of the {{< version-check >}}
shortcode.

* Downgrade warning to note

I don't see any adverse consequences if the reader is unaware that port
forwarding for UDP is not yet implemented.
pull/18660/merge
Tim Bannister 2020-03-16 05:10:35 +00:00 committed by GitHub
parent 83637c1ed2
commit d9a74ae5fc
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
1 changed files with 103 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

155
content/en/docs/tasks/access-application-cluster/port-forward-access-application-cluster.md
View File

@ -2,6 +2,7 @@
title: Use Port Forwarding to Access Applications in a Cluster
content_template: templates/task
weight: 40
min-kubernetes-server-version: v1.10
---
{{% capture overview %}}
@ -26,104 +27,157 @@ for database debugging.
## Creating Redis deployment and service
1. Create a Redis deployment:
1. Create a Deployment that runs Redis:
kubectl apply -f https://k8s.io/examples/application/guestbook/redis-master-deployment.yaml
```shell
kubectl apply -f https://k8s.io/examples/application/guestbook/redis-master-deployment.yaml
```
The output of a successful command verifies that the deployment was created:
deployment.apps/redis-master created
```
deployment.apps/redis-master created
```
View the pod status to check that it is ready:
kubectl get pods
```shell
kubectl get pods
```
The output displays the pod created:
NAME READY STATUS RESTARTS AGE
redis-master-765d459796-258hz 1/1 Running 0 50s
```
NAME READY STATUS RESTARTS AGE
redis-master-765d459796-258hz 1/1 Running 0 50s
```
View the deployment status:
View the Deployment's status:
kubectl get deployment
```shell
kubectl get deployment
```
The output displays that the deployment was created:
The output displays that the Deployment was created:
NAME READY UP-TO-DATE AVAILABLE AGE
redis-master 1/1 1 1 55s
```
NAME READY UP-TO-DATE AVAILABLE AGE
redis-master 1/1 1 1 55s
```
View the replicaset status using:
The Deployment automatically manages a ReplicaSet.
View the ReplicaSet status using:
kubectl get rs
```shell
kubectl get replicaset
```
The output displays that the replicaset was created:
The output displays that the ReplicaSet was created:
NAME DESIRED CURRENT READY AGE
redis-master-765d459796 1 1 1 1m
```
NAME DESIRED CURRENT READY AGE
redis-master-765d459796 1 1 1 1m
```
2. Create a Redis service:
2. Create a Service to expose Redis on the network:
kubectl apply -f https://k8s.io/examples/application/guestbook/redis-master-service.yaml
```shell
kubectl apply -f https://k8s.io/examples/application/guestbook/redis-master-service.yaml
```
The output of a successful command verifies that the service was created:
The output of a successful command verifies that the Service was created:
service/redis-master created
```
service/redis-master created
```
Check the service created:
Check the Service created:
kubectl get svc | grep redis
```shell
kubectl get service redis-master
```
The output displays the service created:
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
redis-master ClusterIP 10.0.0.213 <none> 6379/TCP 27s
```
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
redis-master ClusterIP 10.0.0.213 <none> 6379/TCP 27s
```
3. Verify that the Redis server is running in the pod and listening on port 6379:
3. Verify that the Redis server is running in the Pod, and listening on port 6379:
kubectl get pods redis-master-765d459796-258hz --template='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
```shell
# Change redis-master-765d459796-258hz to the name of the Pod
kubectl get pod redis-master-765d459796-258hz --template='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
```
The output displays the port:
The output displays the port for Redis in that Pod:
6379
```
6379
```
(this is the TCP port allocated to Redis on the internet).
## Forward a local port to a port on the Pod
1. `kubectl port-forward` allows using resource name, such as a pod name, to select a matching pod to port forward to.
## Forward a local port to a port on the pod
1. `kubectl port-forward` allows using resource name, such as a pod name, to select a matching pod to port forward to since Kubernetes v1.10.
kubectl port-forward redis-master-765d459796-258hz 7000:6379
```shell
# Change redis-master-765d459796-258hz to the name of the Pod
kubectl port-forward redis-master-765d459796-258hz 7000:6379
```
which is the same as
kubectl port-forward pods/redis-master-765d459796-258hz 7000:6379
```shell
kubectl port-forward pods/redis-master-765d459796-258hz 7000:6379
```
or
kubectl port-forward deployment/redis-master 7000:6379
```shell
kubectl port-forward deployment/redis-master 7000:6379
```
or
kubectl port-forward rs/redis-master 7000:6379
```shell
kubectl port-forward replicaset/redis-master 7000:6379
```
or
kubectl port-forward svc/redis-master 7000:6379
```shell
kubectl port-forward service/redis-master 7000:6379
```
Any of the above commands works. The output is similar to this:
I0710 14:43:38.274550 3655 portforward.go:225] Forwarding from 127.0.0.1:7000 -> 6379
I0710 14:43:38.274797 3655 portforward.go:225] Forwarding from [::1]:7000 -> 6379
```
I0710 14:43:38.274550 3655 portforward.go:225] Forwarding from 127.0.0.1:7000 -> 6379
I0710 14:43:38.274797 3655 portforward.go:225] Forwarding from [::1]:7000 -> 6379
```
2. Start the Redis command line interface:
redis-cli -p 7000
```shell
redis-cli -p 7000
```
3. At the Redis command line prompt, enter the `ping` command:
127.0.0.1:7000>ping
```
ping
```
A successful ping request returns PONG.
A successful ping request returns:
```
PONG
```
{{% /capture %}}
@ -132,15 +186,15 @@ for database debugging.
## Discussion
Connections made to local port 7000 are forwarded to port 6379 of the pod that
is running the Redis server. With this connection in place you can use your
local workstation to debug the database that is running in the pod.
Connections made to local port 7000 are forwarded to port 6379 of the Pod that
is running the Redis server. With this connection in place, you can use your
local workstation to debug the database that is running in the Pod.
{{< warning >}}
Due to known limitations, port forward today only works for TCP protocol.
The support to UDP protocol is being tracked in
{{< note >}}
`kubectl port-forward` is implemented for TCP ports only.
The support for UDP protocol is tracked in
[issue 47862](https://github.com/kubernetes/kubernetes/issues/47862).
{{< /warning >}}
{{< /note >}}
{{% /capture %}}
@ -148,6 +202,3 @@ The support to UDP protocol is being tracked in
{{% capture whatsnext %}}
Learn more about [kubectl port-forward](/docs/reference/generated/kubectl/kubectl-commands/#port-forward).
{{% /capture %}}