k8s的两种网络方案与多种工作模式[flannel与calico]

k8s的两种网络方案与多种工作模式

1. Flannel:

flannel有三种工作模式:
1. vxlan(隧道方案) 2. host-gw(路由方案)
2. udp(在用户态实现的数据封装解封装,由于性能较差已经被弃用)

vxlan模式:

vxlan模式会在当前服务器中创建一个cni0的网桥,和flannel.1隧道端点. 这个隧道端点会对数据包进行再次封装.然后flannel会把数据包传输到目标节点中.同时它也会在本地创建几个路由表.(可以通过命令 ip route 查看到)
[root@k8s-master1 ~]# ip route
default via 10.0.0.254 dev eth0 
10.0.0.0/24 dev eth0 proto kernel scope link src 10.0.0.63 
10.244.1.0/24 via 10.244.1.0 dev flannel.1 onlink 
10.244.2.0/24 via 10.244.2.0 dev flannel.1 onlink 
169.254.0.0/16 dev eth0 scope link metric 1002 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 

1.1 Flannel网络部署与卸载:

1. 安装flannel网络:
wget https://www.chenleilei.net/soft/k8s/kube-flannel.yaml
kubectl apply -f kube-flannel.yaml

1.1 验证网络:
1.1.1 创建一个应用
kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --target-port=80 --type=NodePort
1.1.2 检查测试:
[root@k8s-master1 ~]# kubectl get pods -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
nginx-f89759699-rcgh2   1/1     Running   0          52s   10.244.2.16   k8s-node2   <none>           <none>
1.1.3 测试flannel网络连通性:
[root@k8s-master1 ~]# ping 10.244.2.16
PING 10.244.2.16 (10.244.2.16) 56(84) bytes of data.
64 bytes from 10.244.2.16: icmp_seq=1 ttl=63 time=0.865 ms
64 bytes from 10.244.2.16: icmp_seq=2 ttl=63 time=0.549 ms

1.1.4 卸载flannel网络:
[root@k8s-master1 ~]# ip route
default via 10.0.0.254 dev eth0 
10.0.0.0/24 dev eth0 proto kernel scope link src 10.0.0.63 
10.244.1.0/24 via 10.244.1.0 dev flannel.1 onlink  # <---flannel网络
10.244.2.0/24 via 10.244.2.0 dev flannel.1 onlink  # <---flannel网络
169.254.0.0/16 dev eth0 scope link metric 1002 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1

[老师提供方法: 所有服务器执行]
ip link delete cni0
ip link delete flannel.1

执行后,检查ip route 查看是否有路由表,flannel网络已经不存在.
[root@k8s-master1 ~]# ip link delete cni0
Cannot find device "cni0"
[root@k8s-master1 ~]# ip link delete flannel.1
[root@k8s-master1 ~]# ip route
default via 10.0.0.254 dev eth0 
10.0.0.0/24 dev eth0 proto kernel scope link src 10.0.0.63 
169.254.0.0/16 dev eth0 scope link metric 1002 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 


1.1.5 测试
[root@k8s-master1 ~]# kubectl get pods -o wide
NAME                    READY   STATUS    RESTARTS   AGE   IP            NODE        NOMINATED NODE   READINESS GATES
nginx-f89759699-rcgh2   1/1     Running   0          23m   10.244.2.16   k8s-node2   <none>           <none>
[root@k8s-master1 ~]# ping 10.244.2.16
PING 10.244.2.16 (10.244.2.16) 56(84) bytes of data.
^C
--- 10.244.2.16 ping statistics ---
68 packets transmitted, 0 received, 100% packet loss, time 68199ms

此时,没有flannel网络的情况下,nginx的这个pod已经无法访问.

在卸载网络插件时无法删除可以使用 --grace-period=0 --force
如:
kubectl delete pod coredns-7ff77c879f-5cc29 -n kube-system --grace-period=0 --force

2. Calico网络部署与卸载

calico有2种中作模式:
1. ipip(隧道方案) 2.bgp(路由方案)

注意: 公有云可能会对路由方案造成影响,并且有的云主机会禁止路由(bgp)方案,所以有些云厂商是禁止此实现方式的,因为他会写入路由表,这样可能会影响到厂商现有网络.

路由方案: 对现有网络有一定的要求,但是他的性能最好,它是直接的路由转发模式,他不会经过数据包封装再封装,没有网络消耗.此方案优先选择,但是也要看厂商是否支持. 它会要求,二层网络可达
隧道方案: 对现有网络要求不高,它只需要三层通信正常基本都可以通信.

 calico网络插件下载:
 官方地址:
 wget https://docs.projectcalico.org/manifests/calico.yaml
 个人网盘地址:
 wget https://www.chenleilei.net/soft/k8s/calico.yaml

注意: 安装calico网络插件 需要卸载 flannel网络插件.

#卸载flannel网络:
ip link delete cni0
ip link delete flannel.1
kubectl delete  -f kube-flannel.yaml

#执行后,检查ip route 查看是否有路由表,flannel网络已经不存在.
[root@k8s-master1 ~]# ip link delete cni0
Cannot find device "cni0"
[root@k8s-master1 ~]# ip link delete flannel.1
[root@k8s-master1 ~]# ip route
default via 10.0.0.254 dev eth0 
10.0.0.0/24 dev eth0 proto kernel scope link src 10.0.0.63 
169.254.0.0/16 dev eth0 scope link metric 1002 
172.17.0.0/16 dev docker0 proto kernel scope link src 172.17.0.1 
 
 
 calico配置:
1.默认网段修改:
找到以下内容:
# - name: CALICO_IPV4POOL_CIDR
#   value: "192.168.0.0/16"
改为安装kubernetes时初始化的网段:
- name: CALICO_IPV4POOL_CIDR
  value: "10.244.0.0/16"
  
 2. 安装calico网络插件 执行yaml
 [root@k8s-master1 ~]# kubectl apply -f calico.yaml 
configmap/calico-config created
customresourcedefinition.apiextensions.k8s.io/bgpconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/bgppeers.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/blockaffinities.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/clusterinformations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/felixconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/globalnetworksets.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/hostendpoints.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamblocks.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamconfigs.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ipamhandles.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/ippools.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/kubecontrollersconfigurations.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networkpolicies.crd.projectcalico.org created
customresourcedefinition.apiextensions.k8s.io/networksets.crd.projectcalico.org created
clusterrole.rbac.authorization.k8s.io/calico-kube-controllers created
clusterrolebinding.rbac.authorization.k8s.io/calico-kube-controllers created
clusterrole.rbac.authorization.k8s.io/calico-node created
clusterrolebinding.rbac.authorization.k8s.io/calico-node created
daemonset.apps/calico-node created
serviceaccount/calico-node created
deployment.apps/calico-kube-controllers created
serviceaccount/calico-kube-controllers created


3. 卸载calico网络插件.
 [root@k8s-master1 ~]# kubectl delete -f calico.yaml 

检查;

kubectl get pods -o wide -n kube-system

2.1 验证与日志检查:

应用创建:
kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --target-port=80 --type=NodePort


日志检查:
[root@k8s-master1 ~]# kubectl get pods -o wide
NAME                    READY  STATUS   RESTARTS  AGE  IP              NODE        NOMINATED NODE   READINESS GATES
nginx-f89759699-qlckm   1/1    Running  0         95s  10.244.169.130  k8s-node2   <none>           <none>

[root@k8s-master1 ~]# curl -I 10.244.169.130
HTTP/1.1 200 OK
Server: nginx/1.19.0
Date: Thu, 18 Jun 2020 12:41:58 GMT
Content-Type: text/html
Content-Length: 612
Last-Modified: Tue, 26 May 2020 15:00:20 GMT
Connection: keep-alive
ETag: "5ecd2f04-264"
Accept-Ranges: bytes

[root@k8s-master1 ~]# kubectl logs nginx-f89759699-qlckm 
10.244.36.64 - - [18/Jun/2020:12:47:09 +0000] "GET /favicon.ico HTTP/1.1" 404 555 "http://10.0.0.65:32746/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.36" "-"

访问没有问题,证明calico网络部署成功.