Cleanup and implement style guidelines. (#18980)

* Reworded paragraphs to reduce ambiguity.
* Added min-kubernetes-server-version metadata.
* Converted yaml to a downloadable resource.
This commit is contained in:
Sharjeel Aziz
2020-02-12 14:06:51 -05:00
committed by GitHub
parent a00f65d84c
commit c8eb9126e9
2 changed files with 46 additions and 48 deletions
@@ -3,6 +3,7 @@ reviewers:
- caseydavenport
- danwinship
title: Declare Network Policy
min-kubernetes-server-version: v1.8
content_template: templates/task
---
{{% capture overview %}}
@@ -30,7 +31,7 @@ The above list is sorted alphabetically by product name, not by recommendation o
## Create an `nginx` deployment and expose it via a service
To see how Kubernetes network policy works, start off by creating an `nginx` deployment.
To see how Kubernetes network policy works, start off by creating an `nginx` Deployment.
```console
kubectl create deployment nginx --image=nginx
@@ -39,7 +40,7 @@ kubectl create deployment nginx --image=nginx
deployment.apps/nginx created
```
And expose it via a service.
Expose the Deployment through a Service called `nginx`.
```console
kubectl expose deployment nginx --port=80
@@ -49,7 +50,7 @@ kubectl expose deployment nginx --port=80
service/nginx exposed
```
This runs a `nginx` pods in the default namespace, and exposes it through a service called `nginx`.
The above commands create a Deployment with an nginx Pod and expose the Deployment through a Service named `nginx`. The `nginx` Pod and Deployment are found in the `default` namespace.
```console
kubectl get svc,pod
@@ -64,59 +65,43 @@ NAME READY STATUS RESTARTS AGE
pod/nginx-701339712-e0qfq 1/1 Running 0 35s
```
## Test the service by accessing it from another pod
## Test the service by accessing it from another Pod
You should be able to access the new `nginx` service from other pods. To test, access the service from another pod in the default namespace. Make sure you haven't enabled isolation on the namespace.
Start a busybox container, and use `wget` on the `nginx` service:
You should be able to access the new `nginx` service from other Pods. To access the `nginx` Service from another Pod in the `default` namespace, start a busybox container:
```console
kubectl run --generator=run-pod/v1 busybox --rm -ti --image=busybox -- /bin/sh
```
```console
Waiting for pod default/busybox-472357175-y0m47 to be running, status is Pending, pod ready: false
In your shell, run the following command:
Hit enter for command prompt
```shell
wget --spider --timeout=1 nginx
```
/ # wget --spider --timeout=1 nginx
```none
Connecting to nginx (10.100.0.16:80)
/ #
remote file exists
```
## Limit access to the `nginx` service
Let's say you want to limit access to the `nginx` service so that only pods with the label `access: true` can query it. To do that, create a `NetworkPolicy` that allows connections only from those pods:
To limit the access to the `nginx` service so that only Pods with the label `access: true` can query it, create a NetworkPolicy object as follows:
```yaml
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: access-nginx
spec:
podSelector:
matchLabels:
app: nginx
ingress:
- from:
- podSelector:
matchLabels:
access: "true"
```
{{< codenew file="service/networking/nginx-policy.yaml" >}}
{{< note >}}
In the case, the label `app=nginx` is automatically added.
NetworkPolicy includes a `podSelector` which selects the grouping of Pods to which the policy applies. You can see this policy selects Pods with the label `app=nginx`. The label was automatically added to the Pod in the `nginx` Deployment. An empty `podSelector` selects all pods in the namespace.
{{< /note >}}
## Assign the policy to the service
Use kubectl to create a NetworkPolicy from the above nginx-policy.yaml file:
Use kubectl to create a NetworkPolicy from the above `nginx-policy.yaml` file:
```console
kubectl apply -f nginx-policy.yaml
kubectl apply -f https://k8s.io/examples/service/networking/nginx-policy.yaml
```
```none
@@ -124,40 +109,40 @@ networkpolicy.networking.k8s.io/access-nginx created
```
## Test access to the service when access label is not defined
If we attempt to access the nginx Service from a pod without the correct labels, the request will now time out:
When you attempt to access the `nginx` Service from a Pod without the correct labels, the request times out:
```console
kubectl run --generator=run-pod/v1 busybox --rm -ti --image=busybox -- /bin/sh
```
```console
Waiting for pod default/busybox-472357175-y0m47 to be running, status is Pending, pod ready: false
In your shell, run the command:
Hit enter for command prompt
```shell
wget --spider --timeout=1 nginx
```
/ # wget --spider --timeout=1 nginx
```none
Connecting to nginx (10.100.0.16:80)
wget: download timed out
/ #
```
## Define access label and test again
Create a pod with the correct labels, and you'll see that the request is allowed:
You can create a Pod with the correct labels to see that the request is allowed:
```console
kubectl run --generator=run-pod/v1 busybox --rm -ti --labels="access=true" --image=busybox -- /bin/sh
```
```console
Waiting for pod default/busybox-472357175-y0m47 to be running, status is Pending, pod ready: false
In your shell, run the command:
Hit enter for command prompt
/ # wget --spider --timeout=1 nginx
Connecting to nginx (10.100.0.16:80)
/ #
```shell
wget --spider --timeout=1 nginx
```
```none
Connecting to nginx (10.100.0.16:80)
remote file exists
```
{{% /capture %}}
@@ -0,0 +1,13 @@
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: access-nginx
spec:
podSelector:
matchLabels:
app: nginx
ingress:
- from:
- podSelector:
matchLabels:
access: "true"