Cis K8S V1120 5.6.1

5.6.1 Create administrative boundaries between resources using namespaces (Manual)

Profile Applicability

• Level 1 - Master Node

Description

Use namespaces to isolate your Kubernetes objects.

Rationale

Limiting the scope of user permissions can reduce the impact of mistakes or malicious activities. A Kubernetes namespace allows you to partition created resources into logically named groups. Resources created in one namespace can be hidden from other namespaces. By default, each resource created by a user in Kubernetes cluster runs in a default namespace, called default. You can create additional namespaces and attach resources and users to them. You can use Kubernetes Authorization plugins to create policies that segregate access to namespace resources between different users.

Impact

You need to switch between namespaces for administration.

Audit Procedure

Run the below command and review the namespaces created in the cluster.

kubectl get namespaces

Ensure that these namespaces are the ones you need and are adequately administered as per your requirements.

Remediation

Follow the documentation and create namespaces for objects in your deployment as you need them.

Default Value

By default, Kubernetes starts with 4 initial namespaces:

1. default - The default namespace for objects with no other namespace
2. kube-system - The namespace for objects created by the Kubernetes system
3. kube-node-lease - Namespace used for node heartbeats
4. kube-public - Namespace used for public information in a cluster

References

1. https://kubernetes.io/docs/concepts/overview/working-with-objects/namespaces/#viewing-namespaces
2. http://blog.kubernetes.io/2016/08/security-best-practices-kubernetes-deployment.html
3. https://github.com/kubernetes/enhancements/tree/master/keps/sig-node/589-efficient-node-heartbeats

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