Focused on sharing DevOps, Kubernetes, Linux, Docker, Istio, microservices, Spring Cloud, Python, Go, databases, Nginx, Tomcat, cloud computing, and related technologies.
This tutorial walks through migrating a two‑node Kubernetes cluster (master and worker) from Docker to containerd on CentOS 7, covering environment setup, node draining, Docker removal, containerd installation and configuration, kubelet adjustments, uncordoning, and verification of the new container runtime.
Ephemeral containers are temporary debugging pods in Kubernetes that lack resource guarantees and cannot restart automatically; this guide explains their differences, enabling the feature via kube-apiserver and kubelet flags, creating a sample Tomcat pod, adding an Ephemeral container with kubectl debug, and updating it using raw API calls.
This guide explains how to run and switch between several Kubernetes clusters on a single server by configuring separate kubeconfig entries, adding clusters, users, and contexts, and using kubectl commands to manage each cluster efficiently.
This article explains Kubernetes networking fundamentals, including intra‑pod communication, pod‑to‑pod traffic, service IP routing, and compares CNI plugins like Flannel and Calico with details on IPIP and BGP optimizations.
This guide explains why routing traffic through an Nginx Ingress controller can halve Kubernetes service QPS and provides step‑by‑step instructions—including switching to IPVS, tuning kernel and file‑descriptor limits, and configuring keep‑alive settings—to restore and even exceed the original performance.
This guide explains why IPVS outperforms iptables for large Kubernetes clusters, then walks through installing ipvsadm, loading kernel modules on master and worker nodes, configuring kube-proxy to use IPVS, cleaning iptables rules, and verifying network and DNS functionality with a BusyBox pod.
This article explains how containers communicate within a pod, between pods, and with services in Kubernetes, and compares Calico's IPIP and BGP networking modes, detailing their traffic handling, suitable scenarios, efficiency, and configuration steps.
This guide explains how to simulate and maintain two separate Kubernetes clusters on a single node by configuring kubeconfig files, adding clusters, users, and contexts, and switching between them to improve DevOps workflow efficiency.
This guide explains the concept of gray (canary) releases and provides detailed Istio configuration files—including Deployments, Service, Gateway, VirtualService, and DestinationRule—to gradually shift traffic between version 1 and version 2 of a service.
This guide explains why default Jenkins slave pods often suffer from slow builds or memory shortages, and provides concrete steps—adjusting CPU/memory limits, trimming plugins, using private artifact stores, disabling workspace cleanup, and configuring parallel stages—to dramatically improve Jenkins performance on Kubernetes.
