Title: How to add users in Kubernetes (K8S)

As an experienced developer, I understand that adding users to a Kubernetes (K8S) cluster is a common task in managing access control. In this article, I will guide you through the process of adding a user to a Kubernetes cluster step by step.

Step-by-Step Guide to Adding a User in Kubernetes:

| Step | Description |
|------|--------------------------------------------|
| 1 | Create a certificate signing request (CSR) |
| 2 | Approve the CSR |
| 3 | Create a Kubernetes user object |
| 4 | Bind the user to a role or cluster role |

Step 1: Create a certificate signing request (CSR)
For creating CSR, you can use the following command:
```bash
openssl req -new -newkey rsa:4096 -nodes -keyout user.key -out user.csr -subj "/CN=user/O=group"
```
- This command generates a private key (user.key) and a certificate signing request (user.csr) for the user with common name "user" and organization "group".

Step 2: Approve the CSR
The CSR needs to be approved by a Kubernetes administrator before a user can be created. Use the following command to approve the CSR:
```bash
kubectl certificate approve user.csr
```
- This command approves the certificate signing request for the user.

Step 3: Create a Kubernetes user object
Create a Kubernetes user object by applying the following YAML configuration:
```yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: User
metadata:
name: user
```
- This YAML configuration creates a Kubernetes user object named "user".

Step 4: Bind the user to a role or cluster role
Finally, bind the user to a Kubernetes role or cluster role using a RoleBinding or ClusterRoleBinding. For example, to bind the user to a role called "editor", use the following YAML configuration:
```yaml
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: user-editor
subjects:
- kind: User
name: user
roleRef:
kind: Role
name: editor
apiGroup: rbac.authorization.k8s.io
```
- This YAML configuration binds the user "user" to the role "editor" using a RoleBinding.

By following these steps, you can successfully add a user to a Kubernetes cluster and manage their access control effectively. Remember to replace placeholders like "user" and "editor" with actual values as needed. Hope this guide helps you in adding users to your Kubernetes cluster efficiently.