This article explains the kube-ovn-cni component of the Kube-OVN project, detailing the CNI workflow, the cmdAdd interface, daemon handling, and the configureNic function that together create and configure pod network interfaces within a Kubernetes cluster.
The Kube-OVN v1.10.0 release introduces Windows node support, user‑defined subnet ACLs, enhanced Kubevirt networking, Submariner multi‑cluster integration, and a series of control‑plane performance optimizations that together improve scalability, flexibility, and stability for cloud‑native Kubernetes deployments.
This article reviews the evolution of cloud‑native networking in China, analyzes platformization and underlay trends, explains the technical challenges of traditional CNI solutions, and details Kube‑OVN's architecture, features, and roadmap as a comprehensive enterprise‑grade Kubernetes networking platform.
This article explains how the Kube-OVN controller manages pod IP and MAC allocation, processes pod add and delete events through a list‑watch mechanism, and details the worker workflow and key functions involved in networking for Kubernetes clusters.
This article provides an in‑depth technical overview of the Kube‑OVN controller, covering its deployment as a Kubernetes deployment, main initialization flow, worker processes for VPC handling, default VPC creation, and related code snippets, illustrating how OpenStack‑style networking is integrated into Kubernetes.
This article presents a detailed technical overview of how ByteDance selected Kube-OVN for a mixed virtual‑machine and container networking scenario, describes the initial network design, identifies performance issues, and outlines three improvement plans including OVS‑DPDK, source‑route optimization, and a switch from Geneve to VXLAN.
This article provides a comprehensive overview of Kubernetes, covering container operation fundamentals, multi‑site deployment models, service discovery mechanisms, shared pod resources, common CNI plugins, layered load‑balancing approaches, isolation dimensions, and essential network model principles for large‑scale clusters.
This article provides a comprehensive overview of Kubernetes architecture, covering its core components, service discovery methods, pod shared resources, common CNI plugins, multi‑layer load balancing, isolation dimensions, and network model principles that enable scalable, high‑availability container operations.
This article provides an in‑depth overview of Kubernetes container operations, covering its core components, multi‑center deployment, four‑layer service discovery, pod resource sharing, common CNI plugins, seven‑layer load balancing, isolation dimensions, and network model principles, while also offering interview resources and community links.
Kubernetes 1.24 introduces 46 enhancements—including dockershim removal, default‑disabled beta APIs, signed release artifacts, OpenAPI v3 support, storage capacity tracking, CSI volume expansion, and new priority options—while also detailing CNI version considerations, upgraded runtimes, and how to access the release notes and tutorials.
This article provides a comprehensive overview of Kubernetes architecture, covering container operations, multi‑center deployment, service discovery mechanisms, shared Pod resources, common CNI plugins, multi‑layer load balancing, isolation dimensions, and network model principles.
Kubernetes 1.24, released in early 2022, introduces 46 enhancements—including the removal of dockershim, default‑off test APIs, signed release artifacts, OpenAPI v3 support, GA storage capacity tracking and volume expansion, new CNI requirements, and numerous API graduations—while also deprecating or deleting several legacy components.
This article explains how Kubernetes ensures container-to-container communication using network namespaces, veth pairs, bridges like docker0, and advanced CNI plugins such as Flannel and Calico, detailing their underlying Linux networking components, routing mechanisms, and deployment considerations for both intra‑host and inter‑host scenarios.
This article examines the performance limitations of Kubernetes pod, service, and network‑policy layers built on the kernel Netfilter framework, explores eBPF‑based alternatives such as tc‑ebpf and Cilium, describes a Terway‑with‑eBPF implementation, and presents benchmark results showing significant latency and scalability improvements.
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 article breaks down Kubernetes' networking model by defining key terms, explaining Service abstractions, IP and port concepts, detailing intra‑cluster communication, and outlining external access methods such as NodePort and Ingress, all supported by practical YAML and command examples.
This article provides a comprehensive overview of Kubernetes, covering its purpose for container operations, key functions, core components, multi‑center deployment, service discovery methods, pod resource sharing, common CNI plugins, load‑balancing layers, isolation dimensions, network model principles, and IP address classifications.
This article provides a comprehensive guide to Kubernetes networking, covering pod network requirements, Linux network namespaces, the role of the pause container, IP allocation, veth pairs, bridge connections, inter‑pod traffic on same and different nodes, CNI plugins, and how services use iptables and conntrack for traffic routing.
This article details how the Kube-OVN community extended the CNI for edge cloud scenarios by adding security‑group based access control, high‑availability virtual IP support, live‑migration‑friendly networking, and smart‑NIC hardware offload, including implementation steps, CRD designs, and relevant pull‑request references.
This article details ByteDance's technical evaluation and implementation of Kube-OVN as a CNI solution for hybrid virtual‑machine and container workloads, covering selection criteria, the initial network design, identified issues, subsequent optimizations, and future roadmap considerations within a cloud‑native Kubernetes environment.
This article explains the fundamentals of container networking in Kubernetes, covering network namespaces, veth pairs, bridges, CNI plugins such as Flannel and Calico, their routing modes, and practical command‑line examples that illustrate intra‑host and cross‑host communication.
This article explains what the Container Network Interface (CNI) is, how Kubernetes uses CNI plugins, and provides a detailed comparison of Overlay, Routing, and Underlay plugins based on environment constraints, functional needs, and performance considerations.
This article walks through Docker's built‑in network drivers—including bridge, host, none, overlay, macvlan and plugins—then dives into Kubernetes networking, detailing Pod communication, the Flannel CNI workflow, and how data traverses virtual bridges and physical interfaces.
This article reviews Du Dongming’s presentation on Kube‑OVN, tracing the evolution of cloud‑native networking from early container experiments to modern multi‑tenant VPC, subnet management, overlay/underlay modes, and the roadmap that positions Kube‑OVN as a comprehensive SDN solution for enterprise Kubernetes environments.
This article provides a comprehensive overview of Kubernetes networking, explaining key concepts such as network namespaces, veth pairs, iptables, services, ClusterIP, NodePort, Ingress, and the role of CNI plugins, while illustrating internal and external communication with practical YAML and kubectl examples.
This article breaks down Kubernetes' internal networking model, explaining key concepts such as network namespaces, veth pairs, iptables, services, ClusterIP, NodePort, and Ingress, and illustrates how pods communicate within a node, across nodes, and how external traffic reaches the cluster.
This article explains the core principles of Kubernetes networking, detailing how each pod receives a unique IP, how intra‑node and inter‑node communication occurs via virtual Ethernet pairs, bridges, and routing, and illustrates packet flow with diagrams to help troubleshoot network issues.
This guide explains how to install and configure k0s, a lightweight Kubernetes distribution, using k0sctl for both standard and high‑availability clusters, covering binary deployment, offline image handling, custom CNI integration, HA load‑balancer setup, certificate management, backup, and advanced features such as etcd replacement and user management.
This article provides a comprehensive overview of Kubernetes architecture, covering its core components, multi‑center deployment, service discovery mechanisms, pod resource sharing, common CNI plugins, load‑balancing layers, isolation dimensions, network model principles, and detailed IP address classifications.
This article introduces Cilium, the eBPF‑based Kubernetes CNI that replaces kube‑proxy, explains its security and scalability advantages over traditional iptables, and provides step‑by‑step guidance for deploying Cilium, testing its connectivity, and using Hubble for deep network visualization integrated with Grafana and Prometheus.
This article explains Kubernetes container networking fundamentals, covering pod-to-pod communication, Linux network namespaces, veth pairs, bridges, and the various CNI plugins such as Flannel and Calico that enable cross‑host networking with overlay, routing, and underlay modes.
The second‑edition Kube‑OVN survey collected 267 valid responses from diverse industries, revealing increased container deployment on virtual machines, a rise in public‑cloud usage, a jump in Kube‑OVN adoption to 40%, growing demand for IPv6/dual‑stack and multi‑tenant networking, and user expectations centered on KubeVirt, VPC enhancements, and eBPF integration.
The article investigates a puzzling Kubernetes issue where using hostPort caused MySQL traffic to be redirected to the wrong pod, explains how iptables rules inserted by the CNI portmap plugin override Service rules, and provides reproducible experiments and practical recommendations to avoid such problems in production.
This tutorial walks through preparing three CentOS 7.6 nodes, installing and configuring containerd, setting up kubeadm, kubelet, and kubectl, initializing a Kubernetes v1.22.1 control plane, adding worker nodes, deploying the Flannel CNI plugin, installing the Kubernetes Dashboard, and providing cleanup commands, all with detailed commands and configuration files.
Kube-OVN 1.8 introduces a re‑engineered Underlay with a new ProviderNetwork CRD supporting flexible NIC and VLAN mappings, achieves roughly 45% latency reduction through flow‑table and kernel optimizations, adds VPC security groups and service support, and bundles several other networking enhancements.
This article explains the core principles of Kubernetes networking, covering pod IP allocation, intra‑node communication via veth pairs and bridges, and inter‑node packet routing using CIDR blocks and cloud provider routes, all illustrated with diagrams.
This article walks through every component that processes a simple `kubectl run` command, from the client’s request parsing, through API‑server authentication, authorization, admission control, controller manager scheduling, to kubelet’s CRI and CNI handling that finally creates the pod and its containers.
This tutorial walks through preparing three CentOS 7.6 nodes, disabling firewalls and SELinux, configuring sysctl and ipvs, installing containerd and its dependencies, generating containerd and kubeadm configurations, initializing the control plane, adding worker nodes, deploying the Flannel CNI plugin and Kubernetes Dashboard, and finally cleaning up the cluster.
This article explains Kubernetes container networking fundamentals, the role of Linux network namespaces, veth pairs, bridges, and iptables, and compares same‑host communication via docker0 with cross‑host solutions like CNI plugins (flannel, Calico) and their routing modes.
This article walks through the complete internal journey of a `kubectl run nginx --image=nginx --replicas=3` command, detailing how the request is validated, authenticated, authorized, processed by the API server, passed through initializers, scheduled, and finally materialized as running pods by kubelet, with code excerpts from Kubernetes v1.21.
This article explains how using hostPort in a Kubernetes cluster injects iptables NAT rules that override normal Service routing, causing unexpected MySQL connection failures, and provides step‑by‑step troubleshooting, reproduction, and recommendations to avoid hostPort in production.
This article walks through installing Cilium as a CNI on a Kubernetes v1.21.3 cluster, disabling kube-proxy, and verifying network connectivity with an Nginx deployment, providing commands, configuration details, and validation steps for a kube‑proxy‑free setup.
This article explains how Kubernetes enables container communication using Linux network namespaces, veth pairs, bridges, iptables, and CNI plugins such as Flannel and Calico, covering both intra‑host networking with docker0 and cross‑host networking modes like overlay, host‑gw, and underlay with BGP routing.
This article provides a comprehensive overview of Kubernetes, covering its purpose for container operations, core components, multi‑site high‑availability design, service discovery mechanisms, pod resource sharing, common CNI plugins, layered load balancing, isolation dimensions, network model principles, and IP address classifications.
This article explains how Kubernetes enables container-to-container communication using network namespaces, veth pairs, bridges, and CNI plugins such as Flannel and Calico, covering both intra‑host networking with docker0 and cross‑host networking models, routing rules, and BGP‑based solutions.
This article explains the fundamentals of container networking in Kubernetes, covering Linux network namespaces, veth pairs, Docker's default bridge, CNI plugins such as Flannel and Calico, their routing modes, and practical command‑line examples for cross‑host communication.
The article outlines Kube‑OVN’s evolution from its 2019 debut to becoming the CNCF‑hosted open‑source CNI with extensive enterprise adoption, details recent feature releases such as multi‑VLAN, BGP, Smart‑NIC, DPDK, dual‑stack and multi‑cluster support, and presents a 2021‑2022 roadmap focusing on performance, security, monitoring and broader cloud‑native use cases.
This article details Qunar's adoption of Calico as a CNI solution, covering its three‑layer architecture, core components, large‑scale deployment practices, IPAM behavior, pod‑to‑pod and pod‑to‑external traffic flows, encountered issues, and the overall benefits for a production Kubernetes environment.
This article provides a comprehensive overview of Kubernetes, covering its core components, container operations, service discovery layers, pod shared resources, common CNI plugins, multi‑layer load balancing, isolation dimensions, network model principles, and various IP address categories for large‑scale deployments.
This article provides a detailed walkthrough of the Calico CNI plugin source code, explaining how the calico and calico‑ipam binaries are built, how the ADD command creates WorkloadEndpoint objects, veth pairs, routes, and sysctl settings, and how these components integrate with the Calico datastore in a Kubernetes environment.
This tutorial walks through installing Containerd on CentOS, pulling and managing a BusyBox container, configuring a CNI bridge network, enabling network access for containers, sharing host directories and PID namespaces, and finally integrating Docker alongside Containerd for a complete container runtime setup.
This article explains Calico’s IPIP networking mode in Kubernetes, detailing its architecture, core components, routing behavior, packet encapsulation, and practical verification through ping tests, route inspection, and packet captures, helping readers understand cross‑node pod communication.
This article examines Calico’s IPIP networking mode in Kubernetes, detailing its architecture, core components, IPIP vs BGP operation, route analysis, packet‑capture findings, and pod‑to‑service communication to illustrate how IP encapsulation facilitates cross‑node traffic.
This article explains common Kubernetes component and node failures, introduces the Node Problem Detector (NPD) for monitoring and reporting issues, and provides step‑by‑step deployment, configuration, and remediation procedures to keep clusters reliable.
This article explains the step‑by‑step process by which kubelet creates a sandbox container, invokes the CNI interface, runs Calico’s ADD command, and sets up routes, virtual interfaces, and IP allocation for pods in a Kubernetes cluster, including relevant Go code excerpts.
This article provides a comprehensive overview of Kubernetes architecture, covering container operations, core components, multi‑center deployment models, service discovery methods, pod resource sharing, CNI plugins, load‑balancing layers, isolation dimensions, network principles, and IP address classifications.
This article explains the fundamental principles of Kubernetes container networking, covering network namespaces, veth pairs, bridges, iptables, and routing, and compares intra‑host communication with cross‑host solutions such as CNI plugins, overlay, host‑gw, and Calico’s BGP‑based approaches.
This article explains the fundamental principles of Kubernetes container networking, how Docker’s default bridge and veth pairs connect pods on the same host, and compares various CNI plugins and routing models for cross‑host communication, including Flannel and Calico.
This guide walks you through using WireGuard for both networking and encryption in cloud‑native Kubernetes, showing how to configure Kilo CNI to create a multi‑cloud k3s mesh across AWS, Azure, GCP and Alibaba Cloud, and how to connect local clients to the cluster.
This article walks through every stage of how Kubernetes creates a pod—from submitting the YAML to the API, through etcd storage, scheduling, kubelet and CRI actions, CNI networking, and endpoint setup for services—providing a clear, step‑by‑step visual guide.
This article explains the fundamental principles of container networking in Kubernetes, covering pod-to-pod communication, Linux network namespaces, veth pairs, Docker bridge, and advanced CNI plugins such as Flannel and Calico, including their overlay, routing, and underlay modes with practical command examples.
This article provides a comprehensive overview of Kubernetes, covering its core components, container deployment and scaling, service discovery methods, shared pod resources, common CNI plugins, multi-layer load balancing, isolation dimensions, network model principles, and IP address classifications for large-scale cloud-native deployments.
This tutorial walks through configuring server hosts, generating TLS certificates with cfssl for etcd and Kubernetes components, deploying an etcd cluster and Kubernetes master services (apiserver, controller‑manager, scheduler) via systemd, setting up kubelet and kube‑proxy on worker nodes, installing Docker, applying Flannel CNI, and adding additional worker nodes to the cluster.
This article explains how Kubernetes networking components—including the container runtime, CRI, CNI plugins, Flannel, and node IPAM—work together to assign unique IP addresses to each Pod across a cluster, covering both same‑host and cross‑host communication mechanisms.
Flannel, a Kubernetes CNI plugin, creates a host overlay network using VXLAN to assign unique virtual IPs to pods, encapsulate traffic, and coordinate routing via etcd, with detailed explanations of its components, packet flow, and underlying Linux networking mechanisms.
This guide explains how Flannel works as a Kubernetes CNI overlay network, detailing its VXLAN mode, the roles of cni0, flannel.1 and flanneld, routing and FDB handling, and provides command‑line examples to trace pod‑to‑pod traffic across nodes.
This article explains why containers and Docker are popular, outlines the network and security challenges of building container cloud platforms, compares bridge, host, container and none networking modes, reviews major CNI solutions such as Calico, Flannel, Weave and Macvlan, and discusses how service mesh complements CNI in multi‑cluster environments.
This comprehensive tutorial walks you through installing a multi-node Kubernetes cluster on CentOS 7.7, covering hardware prerequisites, network setup, Etcd deployment, certificate generation with cfssl, installation of Docker, configuration of master components, worker nodes, CNI networking, CoreDNS, and accessing the Kubernetes dashboard.
This article provides a comprehensive guide to Calico as a Kubernetes CNI, covering its BGP‑based three‑layer architecture, deployment steps, configuration of etcd certificates, management tools, BGP route‑reflector mode, IPIP tunneling, and network policy implementation for cloud‑native clusters.
This article explains Docker’s four network drivers (bridge, host, none, overlay), details how the bridge driver creates the docker0 bridge and veth pairs, shows port‑mapping with -p/-P, then covers Kubernetes pod communication patterns, CNI plugins, and provides a step‑by‑step guide to deploying and configuring Flannel with different backends such as vxlan, host‑gw and directrouting.
This comprehensive guide explains why Kubernetes has become the standard container platform, covering its application‑centric architecture, migration challenges, networking and CNI design, control‑plane components, storage solutions including CSI and FlexVolume, image distribution strategies, upgrade and backup procedures, operator patterns, and practical containerization best practices for large‑scale deployments.
The article summarizes Liu Mengxin’s June 11 talk on cloud‑native networking, covering its definition, basic requirements, open‑source CNI implementations, control‑ and data‑plane designs, and the functional, operational, security, and performance challenges faced when deploying container networks at scale.
The article analyzes a recurring Kubernetes node NotReady problem where restarting kubelet only restores readiness for three minutes, explains the underlying PLEG timeout mechanism, investigates unresponsive Terway CNI plugin behavior, and presents a netlink‑timeout fix to prevent the issue.
This article reviews the SIG Cloud‑Provider‑Alibaba webinar, explains Kubernetes container networking fundamentals, details Alibaba Cloud's high‑performance CNI implementation using Terway with exclusive and shared ENI modes, and shows how eBPF, AutoPath DNS and resource‑pooling improve scalability and latency.
This article explains what the Container Network Interface (CNI) is, how Kubernetes uses CNI plugins, guides the step‑by‑step configuration process, compares Overlay, Routing and Underlay implementations, and provides practical criteria for selecting or building a CNI plugin that fits specific environments and performance needs.
The article presents the launch of Kube-OVN 1.0 GA, shares findings from a 158‑respondent survey on container network usage, outlines current network solutions and future feature demands, and provides a detailed Q&A from the online webinar for practitioners interested in Kubernetes cloud‑native networking.
The article investigates why duplicate UDP packets appear when a client accesses a pod via a Service in Kubernetes bridge mode, analyzes kernel processing with ebpf tool skbtracer, identifies the role of promiscuous mode and packet cloning, and proposes an ebtable rule to eliminate the duplication.
This article details the step‑by‑step evolution of Mafengwo's Kubernetes network—from early Flannel VXLAN setups, through a VPN‑server bridge for external access, to a MAC‑VLAN CNI solution—highlighting design principles, challenges, and recent optimization plans for large‑scale Java micro‑services.
The presentation at the 2019 Shanghai Open Source Infrastructure Summit introduced Kube-OVN, an open‑source CNI that ports mature OpenStack networking concepts to Kubernetes, outlining its design principles, architecture, current release status, and future roadmap.
This article explains Kubernetes’ fundamental network model, detailing the three core constraints and four design goals, exploring network namespaces, comparing Underlay and Overlay approaches, reviewing popular CNI solutions such as Flannel, Calico, Cilium and WeaveNet, and outlining practical NetworkPolicy configuration steps.
This article explains Alibaba Cloud Kubernetes cluster networking, detailing the flannel‑based implementation, the three‑level configuration (cluster, node, pod), the role of Cloud Controller Manager, virtual bridge cni0, and how pods achieve local, intra‑node, inter‑node, and external communication.
Kube‑OVN 0.7.0 introduces IPAM optimizations for StatefulSet, new Subnet CRD status fields, default traffic mirroring, IPv6 control‑plane support, updated documentation, and a detailed TCP performance test showing only a 4% throughput loss for packets larger than 2 KB compared to host networking.
This article explains cloud‑native networking fundamentals, detailing the role of CNI, the high‑performance packet processing capabilities of DPDK and its UIO and poll‑mode drivers, and introduces the Contiv/VPP Kubernetes plugin that leverages VPP for efficient pod‑to‑pod communication.
The latest Kube-OVN release introduces traffic mirroring, IPv6 beta support, an IP‑conflict‑checking webhook, CRD‑based subnet management, and Go module dependency handling, while also summarizing the project’s core networking capabilities and its role in extending Kubernetes with OVN features.
This article explains the practical motivations behind creating Kube-OVN, outlines its design principles, describes its overall architecture and network model, and details key features such as subnet management, IP allocation, QoS, gateway handling, traffic mirroring, and future development plans.
This article explains Kubernetes native NetworkPolicy, covering its purpose, supported CNI plugins, detailed field definitions, default behaviors, example policies, and historical changes, providing a comprehensive guide for configuring pod communication rules in a cloud‑native environment.
UK8S’s custom CNI plugin integrates VPC networking to give containers native cloud performance, but a bug caused kubelet to create a second sandbox container, leading to missing NETNS parameters and VPC IP leaks; the article details the investigation, root‑cause analysis, and the patch fixing the issue.
This article reviews the shortcomings of Kubernetes networking, explains the capabilities of OVS and OVN as unified solutions, maps OVN abstractions to Kubernetes concepts, and outlines future directions for enhancing cloud‑native network functionality, followed by an extensive Q&A session.
Although Docker’s libnetwork/CNM offers a network plugin model, Kubernetes has chosen not to adopt it due to fundamental design mismatches, reliance on low‑level key‑value stores, security and scalability concerns, and a strategic shift toward the simpler, more portable CNI plugin framework.
This article explains the motivation behind the Kubernetes Container Runtime Interface (CRI), outlines its design, and provides a detailed walkthrough of PouchContainer’s CRI manager architecture, including pod creation, network configuration, and I/O stream handling, with code examples and configuration snippets.
This article walks you through deploying Flannel (host‑gw and VXLAN modes) and Calico (IP‑IP mode, RR deployment, and BGP configuration) on a Kubernetes cluster using systemd units, etcd backend settings, and detailed CNI configuration files, complete with troubleshooting tips and code snippets.
This article explains Rancher's use of the CNI specification to build IPsec and VXLAN overlay networks, details the evolution of container networking models, and describes how to configure a flat network using custom bridges and ebtables rules for seamless container communication.
