Cis K8s V200 4.2.7

---
name: cis-k8s-v200-4.2.7
description: "Ensure that the --hostname-override argument is not set (Manual)"
category: cis-k8s
version: "2.0.0"
author: cyberstrike-official
tags: [cis, kubernetes, worker-node, kubelet, hostname, tls]
cis_id: "4.2.7"
cis_benchmark: "CIS Kubernetes Benchmark v2.0.0"
tech_stack: [kubernetes]
cwe_ids: []
chains_with: []
prerequisites: []
severity_boost: {}
---

# 4.2.7 Ensure that the --hostname-override argument is not set (Manual)

## Profile Applicability

- Level 1 - Worker Node

## Description

Do not override node hostnames.

## Rationale

Overriding hostnames could potentially break TLS setup between the kubelet and the apiserver. Additionally, with overridden hostnames, it becomes increasingly difficult to associate logs with a particular node and process them for security analytics. Hence, you should setup your kubelet nodes with resolvable FQDNs and avoid overriding the hostnames with IPs.

## Impact

Some cloud providers may require this flag to ensure that hostname matches names issued by the cloud provider. In these environments, this recommendation should not apply.

## Audit

Run the following command on each node:

```bash
ps -ef | grep kubelet
```

Verify that `--hostname-override` argument does not exist.

**Note** This setting is not configurable via the Kubelet config file.

## Remediation

Edit the kubelet service file `/etc/systemd/system/kubelet.service.d/10-kubeadm.conf` on each worker node and remove the `--hostname-override` argument from the `KUBELET_SYSTEM_PODS_ARGS` variable.

Based on your system, restart the `kubelet` service. For example:

```bash
systemctl daemon-reload
systemctl restart kubelet.service
```

## Default Value

By default, `--hostname-override` argument is not set.

## References

1. https://kubernetes.io/docs/admin/kubelet/
2. https://github.com/kubernetes/kubernetes/issues/22063

## CIS Controls

| Controls Version | Control                                                                                                                                                                                                                                                                                       | IG 1 | IG 2 | IG 3 |
| ---------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---- | ---- | ---- |
| v8               | 4 Secure Configuration of Enterprise Assets and Software - Establish and maintain the secure configuration of enterprise assets (end-user devices, including portable and mobile; network devices; non-computing/IoT devices; and servers) and software (operating systems and applications). |      |      |      |
| v7               | 5 Secure Configuration for Hardware and Software on Mobile Devices, Laptops, Workstations and Servers - Secure Configuration for Hardware and Software on Mobile Devices, Laptops, Workstations and Servers                                                                                   |      |      |      |