IPVS vs. IPTABLES

IPVS模式在Kubernetes 1.8中被引入，在1.9中进入beta测试。 IPTABLES模式在1.1版本中被添加进来，在1.2开始就变成了默认的操作模式。IPVS 和 IPTABLES都是基于netfilter实现的。

IPVS与IPTABLES有以下几点不同的地方:

  1. IPVS为大规模集群提供更好的可扩展性和性能。

  2. IPVS比IPTABLES支持更复杂的负载均衡算法 (least load, least connections, locality, weighted, etc.)。

  3. IPVS支持服务器健康检查和重连等等。

 

配置kube-proxy ipvs模式

k8s版本：1.10

默认情况下，Kube-proxy依然使用iptables来实现Service到POD之间的负载均衡。

[root@node01 ~]# kubectl get svc -o wide
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE       SELECTOR
httpd-svc    ClusterIP   10.110.73.171   <none>        8080/TCP   1d        run=httpd
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP    1d        <none>
[root@node01 ~]# iptables-save
.
.
.
-A KUBE-POSTROUTING -m comment --comment "kubernetes service traffic requiring SNAT" -m mark --mark 0x4000/0x4000 -j MASQUERADE
-A KUBE-SEP-6E7XQMQ4RAYOWTTM -s 10.244.0.3/32 -m comment --comment "kube-system/kube-dns:dns" -j KUBE-MARK-MASQ
-A KUBE-SEP-6E7XQMQ4RAYOWTTM -p udp -m comment --comment "kube-system/kube-dns:dns" -m udp -j DNAT --to-destination 10.244.0.3:53
-A KUBE-SEP-7SDFQQ3CPAUK3SXM -s 10.244.1.2/32 -m comment --comment "default/httpd-svc:" -j KUBE-MARK-MASQ
-A KUBE-SEP-7SDFQQ3CPAUK3SXM -p tcp -m comment --comment "default/httpd-svc:" -m tcp -j DNAT --to-destination 10.244.1.2:80
-A KUBE-SEP-FXPWU3QR6KR3AMXC -s 172.16.65.180/32 -m comment --comment "default/kubernetes:https" -j KUBE-MARK-MASQ
-A KUBE-SEP-FXPWU3QR6KR3AMXC -p tcp -m comment --comment "default/kubernetes:https" -m recent --set --name KUBE-SEP-FXPWU3QR6KR3AMXC --mask 255.255.255.255 --rsource -m tcp -j DNAT --to-destination 172.16.65.180:6443
-A KUBE-SEP-IT2ZTR26TO4XFPTO -s 10.244.0.2/32 -m comment --comment "kube-system/kube-dns:dns-tcp" -j KUBE-MARK-MASQ
-A KUBE-SEP-IT2ZTR26TO4XFPTO -p tcp -m comment --comment "kube-system/kube-dns:dns-tcp" -m tcp -j DNAT --to-destination 10.244.0.2:53
-A KUBE-SEP-TOSIKZVXYIAJSFHP -s 10.244.2.2/32 -m comment --comment "default/httpd-svc:" -j KUBE-MARK-MASQ
-A KUBE-SEP-TOSIKZVXYIAJSFHP -p tcp -m comment --comment "default/httpd-svc:" -m tcp -j DNAT --to-destination 10.244.2.2:80
-A KUBE-SEP-UO4LFRT7VSL3X4EB -s 10.244.0.4/32 -m comment --comment "default/httpd-svc:" -j KUBE-MARK-MASQ
-A KUBE-SEP-UO4LFRT7VSL3X4EB -p tcp -m comment --comment "default/httpd-svc:" -m tcp -j DNAT --to-destination 10.244.0.4:80
-A KUBE-SEP-YIL6JZP7A3QYXJU2 -s 10.244.0.2/32 -m comment --comment "kube-system/kube-dns:dns" -j KUBE-MARK-MASQ
-A KUBE-SEP-YIL6JZP7A3QYXJU2 -p udp -m comment --comment "kube-system/kube-dns:dns" -m udp -j DNAT --to-destination 10.244.0.2:53
-A KUBE-SEP-ZXMNUKOKXUTL2MK2 -s 10.244.0.3/32 -m comment --comment "kube-system/kube-dns:dns-tcp" -j KUBE-MARK-MASQ
-A KUBE-SEP-ZXMNUKOKXUTL2MK2 -p tcp -m comment --comment "kube-system/kube-dns:dns-tcp" -m tcp -j DNAT --to-destination 10.244.0.3:53
-A KUBE-SERVICES ! -s 10.244.0.0/16 -d 10.96.0.1/32 -p tcp -m comment --comment "default/kubernetes:https cluster IP" -m tcp --dport 443 -j KUBE-MARK-MASQ
-A KUBE-SERVICES -d 10.96.0.1/32 -p tcp -m comment --comment "default/kubernetes:https cluster IP" -m tcp --dport 443 -j KUBE-SVC-NPX46M4PTMTKRN6Y
-A KUBE-SERVICES ! -s 10.244.0.0/16 -d 10.96.0.10/32 -p udp -m comment --comment "kube-system/kube-dns:dns cluster IP" -m udp --dport 53 -j KUBE-MARK-MASQ
-A KUBE-SERVICES -d 10.96.0.10/32 -p udp -m comment --comment "kube-system/kube-dns:dns cluster IP" -m udp --dport 53 -j KUBE-SVC-TCOU7JCQXEZGVUNU
-A KUBE-SERVICES ! -s 10.244.0.0/16 -d 10.96.0.10/32 -p tcp -m comment --comment "kube-system/kube-dns:dns-tcp cluster IP" -m tcp --dport 53 -j KUBE-MARK-MASQ
-A KUBE-SERVICES -d 10.96.0.10/32 -p tcp -m comment --comment "kube-system/kube-dns:dns-tcp cluster IP" -m tcp --dport 53 -j KUBE-SVC-ERIFXISQEP7F7OF4
-A KUBE-SERVICES ! -s 10.244.0.0/16 -d 10.110.73.171/32 -p tcp -m comment --comment "default/httpd-svc: cluster IP" -m tcp --dport 8080 -j KUBE-MARK-MASQ
-A KUBE-SERVICES -d 10.110.73.171/32 -p tcp -m comment --comment "default/httpd-svc: cluster IP" -m tcp --dport 8080 -j KUBE-SVC-RL3JAE4GN7VOGDGP
-A KUBE-SERVICES -m comment --comment "kubernetes service nodeports; NOTE: this must be the last rule in this chain" -m addrtype --dst-type LOCAL -j KUBE-NODEPORTS
-A KUBE-SVC-ERIFXISQEP7F7OF4 -m comment --comment "kube-system/kube-dns:dns-tcp" -m statistic --mode random --probability 0.50000000000 -j KUBE-SEP-IT2ZTR26TO4XFPTO
-A KUBE-SVC-ERIFXISQEP7F7OF4 -m comment --comment "kube-system/kube-dns:dns-tcp" -j KUBE-SEP-ZXMNUKOKXUTL2MK2
-A KUBE-SVC-NPX46M4PTMTKRN6Y -m comment --comment "default/kubernetes:https" -m recent --rcheck --seconds 10800 --reap --name KUBE-SEP-FXPWU3QR6KR3AMXC --mask 255.255.255.255 --rsource -j KUBE-SEP-FXPWU3QR6KR3AMXC
-A KUBE-SVC-NPX46M4PTMTKRN6Y -m comment --comment "default/kubernetes:https" -j KUBE-SEP-FXPWU3QR6KR3AMXC
-A KUBE-SVC-RL3JAE4GN7VOGDGP -m comment --comment "default/httpd-svc:" -m statistic --mode random --probability 0.33332999982 -j KUBE-SEP-UO4LFRT7VSL3X4EB
-A KUBE-SVC-RL3JAE4GN7VOGDGP -m comment --comment "default/httpd-svc:" -m statistic --mode random --probability 0.50000000000 -j KUBE-SEP-7SDFQQ3CPAUK3SXM
-A KUBE-SVC-RL3JAE4GN7VOGDGP -m comment --comment "default/httpd-svc:" -j KUBE-SEP-TOSIKZVXYIAJSFHP
-A KUBE-SVC-TCOU7JCQXEZGVUNU -m comment --comment "kube-system/kube-dns:dns" -m statistic --mode random --probability 0.50000000000 -j KUBE-SEP-YIL6JZP7A3QYXJU2
-A KUBE-SVC-TCOU7JCQXEZGVUNU -m comment --comment "kube-system/kube-dns:dns" -j KUBE-SEP-6E7XQMQ4RAYOWTTM
.
.
.

 

第一步，在内核中加载ip_vs模块：

cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
ipvs_modules="ip_vs ip_vs_lc ip_vs_wlc ip_vs_rr ip_vs_wrr ip_vs_lblc ip_vs_lblcr ip_vs_dh ip_vs_sh ip_vs_nq ip_vs_sed ip_vs_ftp nf_conntrack_ipv4"
for kernel_module in \${ipvs_modules}; do
    /sbin/modinfo -F filename \${kernel_module} > /dev/null 2>&1
    if [ $? -eq 0 ]; then
        /sbin/modprobe \${kernel_module}
    fi
done
EOF
chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep ip_vs

输出结果应该为：

[root@node01 ~]# lsmod | grep ip_vs
ip_vs_ftp              13079  0 
ip_vs_sed              12519  0 
ip_vs_nq               12516  0 
ip_vs_sh               12688  0 
ip_vs_dh               12688  0 
ip_vs_lblcr            12922  0 
ip_vs_lblc             12819  0 
ip_vs_wrr              12697  0 
ip_vs_rr               12600  3 
ip_vs_wlc              12519  0 
ip_vs_lc               12516  0 
nf_nat                 26787  3 ip_vs_ftp,nf_nat_ipv4,nf_nat_masquerade_ipv4
ip_vs                 141092  27 ip_vs_dh,ip_vs_lc,ip_vs_nq,ip_vs_rr,ip_vs_sh,ip_vs_ftp,ip_vs_sed,ip_vs_wlc,ip_vs_wrr,ip_vs_lblcr,ip_vs_lblc
nf_conntrack          133387  7 ip_vs,nf_nat,nf_nat_ipv4,xt_conntrack,nf_nat_masquerade_ipv4,nf_conntrack_netlink,nf_conntrack_ipv4
libcrc32c              12644  4 xfs,ip_vs,nf_nat,nf_conntrack

 

第二步，安装ipvs管理工具ipvsadm

yum install -y ipvsadm

 

第三步，修改集群配置文件

在使用kubeadm init --config config.yaml初始化集群前，修改集群配置文件

Kubernetes v1.8 v1.9
kind: MasterConfiguration
apiVersion: kubeadm.k8s.io/v1alpha1
...
kubeProxy:
  config:
    featureGates: SupportIPVSProxyMode=true
    mode: ipvs
...

Kubernetes v1.10
kind: MasterConfiguration
apiVersion: kubeadm.k8s.io/v1alpha1
...
kubeProxy:
  config:
    featureGates: 
      SupportIPVSProxyMode: true
    mode: ipvs
...

 

第四步，结果验证

[root@node01 ~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.96.0.1:443 rr persistent 10800
  -> 172.16.65.180:6443           Masq    1      3          0         
TCP  10.96.0.10:53 rr
  -> 10.244.0.2:53                Masq    1      0          0         
  -> 10.244.0.3:53                Masq    1      0          0         
UDP  10.96.0.10:53 rr
  -> 10.244.0.2:53                Masq    1      0          0         
  -> 10.244.0.3:53                Masq    1      0          0

 

第五步，测试

创建http-svc service

apiVersion: apps/v1beta1
kind: Deployment
metadata:
  name: httpd
spec:
  replicas: 3
  template:
    metadata:
      labels:
        run: httpd
    spec:
      containers:
      - name: httpd
        image: httpd
        ports:
        - containerPort: 80

---
apiVersion: v1
kind: Service
metadata:
  name: httpd-svc
spec:
  selector:
    run: httpd
  type: NodePort
  ports:
  - protocol: TCP
    port: 8080
    targetPort: 80
    nodePort: 30001

查看效果

[root@node01 yaml-store]# kubectl get pod -o wide
NAME                     READY     STATUS    RESTARTS   AGE       IP           NODE
httpd-749bf8c6f4-htzgl   1/1       Running   0          11m       10.244.2.2   node03
httpd-749bf8c6f4-vqwff   1/1       Running   0          11m       10.244.1.2   node02
httpd-749bf8c6f4-wkv9w   1/1       Running   0          11m       10.244.0.4   node01

[root@node01 yaml-store]# kubectl get svc -o wide
NAME         TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE       SELECTOR
httpd-svc    ClusterIP   10.99.129.90   <none>        8080:30001/TCP   11m       run=httpd
kubernetes   ClusterIP   10.96.0.1      <none>        443/TCP    58m       <none>
[root@node01 yaml-store]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.16.65.181:30001 rr
  -> 10.244.0.4:80                Masq    1      0          0         
  -> 10.244.1.2:80                Masq    1      0          0         
  -> 10.244.2.2:80                Masq    1      0          0         
TCP  172.17.0.1:30001 rr
  -> 10.244.0.4:80                Masq    1      0          0         
  -> 10.244.1.2:80                Masq    1      0          0         
  -> 10.244.2.2:80                Masq    1      0          0         
TCP  10.96.0.1:443 rr persistent 10800
  -> 172.16.65.180:6443           Masq    1      3          0         
TCP  10.96.0.10:53 rr
  -> 10.244.0.2:53                Masq    1      0          0         
  -> 10.244.0.3:53                Masq    1      0          0         
TCP  10.99.129.90:8080 rr
  -> 10.244.0.4:80                Masq    1      0          0         
  -> 10.244.1.2:80                Masq    1      0          0         
  -> 10.244.2.2:80                Masq    1      0          0         
TCP  10.244.0.0:30001 rr
  -> 10.244.0.4:80                Masq    1      0          0         
  -> 10.244.1.2:80                Masq    1      0          0         
  -> 10.244.2.2:80                Masq    1      0          0         
TCP  10.244.0.1:30001 rr
  -> 10.244.0.4:80                Masq    1      0          0         
  -> 10.244.1.2:80                Masq    1      0          0         
  -> 10.244.2.2:80                Masq    1      0          0         
TCP  127.0.0.1:30001 rr
  -> 10.244.0.4:80                Masq    1      0          0         
  -> 10.244.1.2:80                Masq    1      0          0         
  -> 10.244.2.2:80                Masq    1      0          0         
UDP  10.96.0.10:53 rr
  -> 10.244.0.2:53                Masq    1      0          0         
  -> 10.244.0.3:53                Masq    1      0          0

 

参考文章：

https://github.com/kubernetes/kubernetes/tree/master/pkg/proxy/ipvs

https://www.kubernetes.org.cn/3025.html

 

转载于:https://www.cnblogs.com/vincenshen/p/8983369.html

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