87 lines
3.1 KiB
Markdown
87 lines
3.1 KiB
Markdown
---
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assignees:
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- thockin
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- caseydavenport
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---
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* TOC
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{:toc}
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A network policy is a specification of how selections of pods are allowed to communicate with each other and other network endpoints.
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`NetworkPolicy` resources use labels to select pods and define whitelist rules which allow traffic to the selected pods in addition to what is allowed by the isolation policy for a given namespace.
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## Prerequisites
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You must enable the `extensions/v1beta1/networkpolicies` runtime config in your apiserver to enable this resource.
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You must also be using a networking solution which supports `NetworkPolicy` - simply creating the
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resource without a controller to implement it will have no effect.
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## Configuring Namespace Isolation Policy
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Isolation can be configured on a per-namespace basis. Once isolation is configured on a namespace it will be applied to all pods in that namespace. Currently, only isolation policy on inbound traffic (ingress) can be defined.
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The following ingress isolation types being supported:
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- `DefaultDeny`: Pods in the namespace will be inaccessible from any source except the pod's local node.
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Ingress isolation can be enabled using an annotation on the Namespace.
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```yaml
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kind: Namespace
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apiVersion: v1
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metadata:
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annotations:
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net.beta.kubernetes.io/network-policy: |
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{
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"ingress": {
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"isolation": "DefaultDeny"
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}
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}
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```
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To configure the annotation via `kubectl`:
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```shell{% raw %}
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kubectl annotate ns <namespace> "net.beta.kubernetes.io/network-policy={\"ingress\": {\"isolation\": \"DefaultDeny\"}}"
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{% endraw %}```
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See the [NetworkPolicy getting started guide](/docs/getting-started-guides/network-policy/walkthrough) for an example.
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## The `NetworkPolicy` Resource
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See the [api-reference](/docs/api-reference/extensions/v1beta1/definitions/#_v1beta1_networkpolicy) for a full definition of the resource.
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A minimal `NetworkPolicy` might look like this:
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```yaml
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apiVersion: extensions/v1beta1
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kind: NetworkPolicy
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metadata:
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name: test-network-policy
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spec:
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podSelector:
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matchLabels:
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role: db
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ingress:
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- from:
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- podSelector:
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matchLabels:
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role: frontend
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ports:
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- protocol: tcp
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port: 6379
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```
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*POSTing this to the API server will have no effect unless your chosen networking solution supports network policy.*
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__Mandatory Fields__: As with all other Kubernetes config, a `NetworkPolicy` needs `apiVersion`, `kind`, and `metadata` fields. For general information about working with config files, see [here](/docs/user-guide/simple-yaml), [here](/docs/user-guide/configuring-containers), and [here](/docs/user-guide/working-with-resources).
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__spec__: `NetworkPolicy` [spec](https://github.com/kubernetes/kubernetes/tree/{{page.githubbranch}}/docs/devel/api-conventions.md#spec-and-status) has all the information needed to define a network isolation policy in the deployed controller.
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__podSelector__: Each `NetworkPolicy` includes a `podSelector` which selects the grouping of pods to which the `ingress` rules in the policy apply.
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__ingress__: Each `NetworkPolicy` includes a list of whitelist `ingress` rules. Each rule allows traffic which matches both the `from` and `ports` sections.
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