Have you created custom configuration files for Kubernetes from scratch?

Yes, creating custom configuration files for Kubernetes from scratch is a common practice when setting up applications and infrastructure.

Configuration files are usually written in YAML format and describe Kubernetes objects such as Pod, Deployment, Service, ConfigMap, and others.

A simple Deployment example for a Python application:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: python-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: python-app
  template:
    metadata:
      labels:
        app: python-app
    spec:
      containers:
      - name: python-container
        image: python:3.9-slim
        command: ["python", "-m", "http.server", "8000"]
        ports:
        - containerPort: 8000

Such a file can be created manually, adapting it to the application's and infrastructure's requirements. This allows flexible management of deployment and scaling of services in Kubernetes.