History

Kubernetes Submit Queue 830a363598 Merge pull request #51874 from vfreex/fix-ipvs-check Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>. kube-proxy IPVS: Fix IPVS availability check What this PR does / why we need it: The current implementation of `CanUseIPVSProxier()` reads `/proc/modules` to check whether IPVS related kernel modules can be loaded. You might get a false-negative when the kernel modules are installed to the system but haven't been loaded into the kernel. This patch firstly try to run `modprobe` to load specified kernel modules, then just log warnings if error occured. Secondly, it will check loaded kernel modules by reading `/proc/modules`, return an error if any required module is missing. This change will not break the compatability of existing implementation. Running kube-proxy in a container without mounting `/lib/modules` will cause `modprobe` warnings, but not raise an error if all required modules are present in the host kernel. Special notes for your reviewer: Release note: ```release-note Fix IPVS availability check ```		2017-11-03 09:04:25 -07:00
..
testing	remove +linux restriction in ipvs/fake	2017-10-27 11:44:02 +08:00
BUILD	add proxy metrics in app level	2017-10-16 21:10:51 +08:00
netlink_linux.go	fix duplicate unbind action	2017-10-09 12:14:24 +08:00
netlink_unsupported.go	fix duplicate unbind action	2017-10-09 12:14:24 +08:00
netlink.go	fix duplicate unbind action	2017-10-09 12:14:24 +08:00
proxier_test.go	fix duplicate unbind action	2017-10-09 12:14:24 +08:00
proxier.go	Merge pull request #51874 from vfreex/fix-ipvs-check	2017-11-03 09:04:25 -07:00
README.md	update readme in ipvs proxy	2017-11-02 12:19:03 +08:00

README.md

How to use IPVS

This document shows how to use kube-proxy ipvs mode.

What is IPVS

IPVS (IP Virtual Server) implements transport-layer load balancing, usually called Layer 4 LAN switching, as part of Linux kernel.

IPVS runs on a host and acts as a load balancer in front of a cluster of real servers. IPVS can direct requests for TCP and UDP-based services to the real servers, and make services of real servers appear as irtual services on a single IP address.

How to use

Load IPVS kernel modules

Currently the IPVS kernel module can't be loaded automatically, so first we should use the following command to load IPVS kernel modules manually.

modprobe ip_vs
modprobe ip_vs_rr
modprobe ip_vs_wrr
modprobe ip_vs_sh
modprobe nf_conntrack_ipv4

After that, use lsmod | grep ip_vs to make sure kernel modules are loaded.

Run kube-proxy in ipvs mode

Local UP Cluster

Kube-proxy will run in iptables mode by default in a local-up cluster.

Users should export the env KUBEPROXY_MODE=ipvs to specify the ipvs mode before deploying the cluster if want to run kube-proxy in ipvs mode.

Cluster Created by Kubeadm

Kube-proxy will run in iptables mode by default in a cluster deployed by kubeadm.

Since IPVS mode is still feature-gated, users should add the flag --feature-gates=SupportIPVSProxyMode=true in kubeadm init command

kubeadm init --feature-gates=SupportIPVSProxyMode=true

to specify the ipvs mode before deploying the cluster if want to run kube-proxy in ipvs mode.

Test

Use ipvsadm tool to test whether the kube-proxy start succeed. By default we may get result like:

# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.0.0.1:443 rr persistent 10800
  -> 10.229.43.2:6443             Masq    1      0          0         
TCP  10.0.0.10:53 rr      
UDP  10.0.0.10:53 rr