Kubernetes Volumes and Persistent Volumes Explained
Containers are ephemeral by nature, meaning data stored inside them disappears when a pod is restarted. To persist data in Kubernetes, we use Volumes and Persistent Volumes.
- Kubernetes Volumes: Basics
A Volume in Kubernetes provides storage that can be shared across containers within a pod. Unlike a container’s filesystem, a Kubernetes volume exists as long as the pod exists.
Types of Kubernetes Volumes:
Volume Type Description emptyDir Temporary storage that exists while the pod is running. hostPath Mounts a directory from the worker node’s filesystem. configMap / secret Mounts a ConfigMap or Secret as a file. persistentVolumeClaim Connects to a Persistent Volume (PV) for long-term storage.
Managing Kubernetes ConfigMaps and Secrets
Applications running in Kubernetes often require configuration settings such as database URLs, API keys, and environment variables. Kubernetes provides two key resources for managing this configuration data:
- ConfigMaps – Store non-sensitive configuration data like environment variables and configuration files.
- Secrets – Store sensitive information like passwords, tokens, and certificates securely.
What is a ConfigMap?
A ConfigMap allows you to store configuration data separately from your application code. This enables dynamic configuration updates without modifying container images.
Understanding Kubernetes Architecture
Kubernetes is a powerful container orchestration system that automates the deployment, scaling, and management of containerized applications. To fully understand how Kubernetes operates, we must first explore its architecture and components.
High-Level Overview
A Kubernetes cluster consists of two main components:
- Control Plane (Master Node): Manages the cluster and ensures the desired state of applications.
- Worker Nodes: Execute containerized applications and respond to instructions from the control plane.
Understanding Kubernetes Pods, Deployments, and ReplicaSets
Kubernetes manages containerized applications using fundamental building blocks like Pods, Deployments, and ReplicaSets. These concepts enable scalable, resilient, and automated deployments.
What is a Pod?
A Pod is the smallest deployable unit in Kubernetes. It represents one or more containers that share the same network namespace and storage.
Key Features of a Pod:
- Can contain one or multiple containers.
- Shares network and storage among containers in the pod.
- Has a unique IP address inside the cluster.
Example: A Simple Pod Manifest
Understanding Kubernetes Services: ClusterIP, NodePort, LoadBalancer, and ExternalName
In Kubernetes, Pods are ephemeral, meaning they can be created and destroyed dynamically. To allow stable communication between different components of an application, Kubernetes provides Services.
A Service exposes a set of Pods using a stable IP and DNS name, ensuring reliable networking within and outside the cluster.
Why Do We Need Kubernetes Services?
- Pods have dynamic IP addresses that change when restarted.
- Services provide a fixed virtual IP (VIP) that remains stable.
- Services enable load balancing across multiple pod instances.
Types of Kubernetes Services
Kubernetes provides four main types of services:
A Comprehensive Guide to Helm Charts with Examples
Helm is a powerful package manager for Kubernetes that simplifies the deployment, management, and scaling of applications. Instead of manually defining complex Kubernetes YAML files, you can use Helm charts, which provide a structured and reusable way to deploy applications.
In this guide, we will explore:
- What Helm charts are
- Their key components
- How to create and deploy a Helm chart
- A practical example
Calling an API Using Microsoft Forms and Power Automate
Microsoft Forms is a simple way to collect user input, and Power Automate can process that data by triggering API calls. This guide will walk you through the process of capturing responses from a Microsoft Form and sending them to an external API.
Prerequisites
Before starting, ensure you have: • A Microsoft 365 account • Access to Microsoft Forms • A Power Automate (Flow) license • An API endpoint to call
Quantifying the Business Value of Paying Off Tech Debt
It’s a very common scenario — The product owner chooses new features regularly and seldom picks tech debt. In the end, the crashes have to be fixed, and the tech debt is growing. Those problems are slowing down testing and development._
Besides, the team have new great ideas to optimize the software, but the product owner has difficulty to estimate their values, and priorities them.
What actions could you take to resolve the issues?
Understanding HTTPS: How It Works and How to Set It Up Locally, in Test, and in Production
HTTPS (Hypertext Transfer Protocol Secure) is the secure version of HTTP, the protocol used for communication between a web browser and a web server. It ensures that all data exchanged is encrypted, maintaining confidentiality and integrity.
Git Commit Convention: A Guide to Writing Meaningful Commit Messages
In software development, version control is crucial for tracking changes and collaborating effectively. Git, one of the most widely used version control systems, allows developers to commit changes with messages that describe what was modified. However, without a proper structure, commit messages can become inconsistent, unclear, or even useless.
A Git Commit Convention provides a standardized way to write commit messages, making them more readable, understandable, and useful for developers, reviewers, and future maintainers.