Change:
mode: ipvs ... ``` <ins> before running `kube init --config <path_to_configuration_file>` If you are using Kubernetes v1.8, you can also add the flag `--feature-gates=SupportIPVSProxyMode=true` (deprecated since v1.9) in `kubeadm init` command ``` kubeadm init --feature-gates=SupportIPVSProxyMode=true ``` to specify the ipvs mode before deploying the cluster. **Notes** If ipvs mode is successfully on, you should see ipvs proxy rules (use `ipvsadm`) like ```shell # 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 -> 192.168.0.1:6443             Masq    1      1          0 ``` or similar logs occur in kube-proxy logs (for example, `/tmp/kube-proxy.log` for local-up cluster)  when the local cluster is running: ``` Using ipvs Proxier. ``` While there is no ipvs proxy rules or the following logs ocuurs indicate that the kube-proxy fails to use ipvs mode: ``` Can't use ipvs proxier, trying iptables proxier Using iptables Proxier. ``` See the following section for more details on debugging. </ins> ## Debug ### Check IPVS proxy rules <del> People can use `ipvsadm` tool to check whether kube-proxy are maintaining IPVS rules correctly. For example, we may get IPVS proxy rules like: </del> <ins> Users can use `ipvsadm` tool to check whether kube-proxy are maintaining IPVS rules correctly. For example, we have the following services in the cluster: ``` # kubectl get svc --all-namespaces NAMESPACE     NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)         AGE default       kubernetes   ClusterIP   10.0.0.1     <none>        443/TCP         1d kube-system   kube-dns     ClusterIP   10.0.0.10    <none>        53/UDP,53/TCP   1d ``` We may get IPVS proxy rules like: </ins> ```shell <del> # ipvsadm -ln </del> <ins> # ipvsadm -ln </ins> 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 <del> -> 10.229.43.2:6443             Masq    1      0          0 TCP  10.0.0.10:53 rr </del> <ins> -> 192.168.0.1:6443             Masq    1      1          0 TCP  10.0.0.10:53 rr -> 172.17.0.2:53                Masq    1      0          0 </ins> UDP  10.0.0.10:53 rr <ins> -> 172.17.0.2:53                Masq    1      0          0 </ins> ``` ### Why kube-proxy can't start IPVS mode <del> People can do the following check list step by step: </del> <ins> Use the following check list to help you solve the problems: </ins> **1. Enable IPVS feature gateway** <del> Currently IPVS-based kube-proxy is still in alpha phase, people need to enable `--feature-gates=SupportIPVSProxyMode=true` explicitly. </del> <ins> For Kubernetes v1.10 and later, feature gate `SupportIPVSProxyMode` is set to `true` by default. However, you need to enable `--feature-gates=SupportIPVSProxyMode=true` explicitly for Kubernetes before v1.10. </ins> **2. Specify proxy-mode=ipvs** <del> Tell kube-proxy that proxy-mode=ipvs, please. </del> <ins> Check whether the kube-proxy mode has been set to `ipvs`. </ins> <del> **3. Load ipvs required kernel modules** The following kernel modules are required by IPVS-based kube-proxy: ```shell ip_vs ip_vs_rr ip_vs_wrr ip_vs_sh nf_conntrack_ipv4 ``` </del> <ins> **3. Install required kernel modules and packages** </ins> <del> IPVS-based kube-proxy will load them automatically. If it fails to load them, please check whether they are compiled into your kernel. </del> <ins> Check whether the ipvs required kernel modules have been compiled into the kernel and packages installed. (see Prerequisite) </ins>  No newline at end of file

Discussion:
/kind documentation What happened: IPVS needs to be documented more. Specifically, the existing documentation needs to be updated to properly describe how to bring up a cluster with ipvs in the kubeadm, local and gce case. Furthermore, there needs to be another piece of documentation that describes the main differences between iptables and ipvs and also dives into implementation differences between the two (ex. ipset). It would also be really nice if there could be some screenshots detailing the difference between iptables and ipvs rules (i.e bring up a cluster, create a service, dump iptables and ipvs rules, compare) All this documentation should be to pkg/proxy/ipvs /assign /area ipvs /sig network