Parameter: -proxy-mode In addition to existing userspace and iptables modes, IPVS mode is configured via -proxy-mode=ipvs.

IPVS is specifically designed for load balancing and uses more efficient data structures (hash tables) allowing for almost unlimited scale under the hood. On the other hand, using IPVS-based in-cluster service load balancing can help a lot for such cases. One example is that with NodePort Service in a 5000-node cluster, if we have 2000 services and each services have 10 pods, this will cause at least 20000 iptable records on each worker node, and this can make the kernel pretty busy. However, iptables struggles to scale to tens of thousands of Services because it is designed purely for firewalling purposes and is based on in-kernel rule lists.Įven though Kubernetes already support 5000 nodes in release v1.6, the kube-proxy with iptables is actually a bottleneck to scale the cluster to 5000 nodes. Kube-proxy, the building block of service routing has relied on the battle-hardened iptables to implement the core supported Service types such as ClusterIP and NodePort. In particular, the scalability of services is paramount to the adoption of Kubernetes by developers/companies running large workloads. Why IPVS for Kubernetes?Īs Kubernetes grows in usage, the scalability of its resources becomes more and more important. Therefore, IPVS naturally supports Kubernetes Service. IPVS can direct requests for TCP- and UDP-based services to the real servers, and make services of the real servers appear as virtual services on a single IP address. IPVS is incorporated into the LVS (Linux Virtual Server), where it runs on a host and acts as a load balancer in front of a cluster of real servers. IPVS ( IP Virtual Server) is built on top of the Netfilter and implements transport-layer load balancing as part of the Linux kernel. In this blog, we will take you through a deep dive of the feature.

Per the Kubernetes 1.11 release blog post, we announced that IPVS-Based In-Cluster Service Load Balancing graduates to General Availability. Author: Jun Du(Huawei), Haibin Xie(Huawei), Wei Liang(Huawei)Įditor’s note: this post is part of a series of in-depth articles on what’s new in Kubernetes 1.11 Introduction

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