Kubectl Commands General Information kubectl can be replaced with k by using an alias. kubectl makes calls to the kube-apiserver behind the scenes. Get or List Resources List all K8s objects:

List nodes:

List pods:

List pods with additional info:

List services:

or

List deployments:

List replica sets:…

Networking in Kubernetes Networking in a Single Node When Kubernetes (K8s) is installed on a host, it creates an internal private network in the range 10.244.0.0/16. Every pod on the host receives an IP address within this network. The pods can communicate with each other using IP addresses, but relying on IP addresses is not…

Labels, Selectors, and Annotations in Kubernetes Labels and Selectors are essential in Kubernetes for organizing and selecting resources. By labeling each Kubernetes resource, you can later use selectors to filter and apply actions to those resources. Working with Labels and Selectors To retrieve pods with a specific label, you can use the following command:

…

YAML Definition File for Kubernetes

Key Concepts in Kubernetes YAML Config Files: apiVersion: Type: String Description: Specifies the API version for the Kubernetes object you’re creating. The correct API version depends on the kind of Kubernetes object you’re defining. Example: apiVersion: v1 kind: Type: String Description: Indicates the type of Kubernetes object being created…

Introduction to Kubernetes Kubernetes is an open-source container orchestration tool developed by Google. It plays a crucial role in managing containerized applications across different deployment environments, ensuring they run efficiently and reliably. Understanding Virtual Machines (VMs) Before diving into containers and Kubernetes, it’s essential to understand what a Virtual Machine (VM) is. A VM is…

CKA Tips for Kubernetes 1.30 In this section, we’ll provide some tips on how to handle the CKA exam and browser terminal effectively. Knowledge Study all topics as proposed in the curriculum until you feel comfortable with them. General Do 1 or 2 test sessions with the CKA Simulator. Understand the solutions and try out…

Step 1: Create the Pod and Service To begin, create a Pod named check-ip in the default namespace and expose it via a ClusterIP Service: Step 2: Retrieve the IP of the Service Retrieve the ClusterIP of the check-ip-service to check its initial configuration: Step 3: Change the Service CIDR To change the Service CIDR…

Verifying kube-proxy Functionality in Kubernetes by Using iptables In Kubernetes, kube-proxy is responsible for maintaining network rules on nodes, ensuring that communication between services is correctly routed. This post walks through the process of verifying that kube-proxy is functioning correctly on all nodes by using iptables. We’ll create a test Pod and Service, check the…

Gathering etcd Information and Taking a Snapshot in Kubernetes In a Kubernetes cluster, etcd is a critical component that stores the cluster’s configuration and state. Managing and securing etcd is essential for ensuring the reliability of your Kubernetes cluster. In this guide, we’ll walk through how to gather key information about etcd, including the server…

Manually Accessing the Kubernetes API with a ServiceAccount Using Curl Accessing the Kubernetes API manually can be a powerful way to interact with your cluster and understand its internals. In this guide, we’ll walk through the process of creating a Pod that uses a specific ServiceAccount and then using curl to access the Kubernetes API,…