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10-K8S之pod网络插件Flannel和canel(网络策略)

作者:互联网

目录

配置网络插件flannel

# docker 4种网络模型
docker
  bridge:自由网络名称空间
  joined:共享使用另一个容器的名称空间
  host(open):容器共享宿主机的网络名称空间
  none(closed):不使用任何网络名称空间
kubernetes集群的管理方式:
  1.容器间通信:同一个pod内的多个容器间的通信,lo
  2.Pod通信:Pod IP<-->Pod IP
  3.Pod与Service通信:Pod IP<-->Cluster IP
  4.Service与集群外部客户端的通信;
CNI:container network interface,容器网络接口
    flannel:地址分配,网络管理
    calico:地址分配,网络管理,网络策略
    canel
    kube-router
    ...

解决方案:
  虚拟网桥
  多路复用:MacVLAN
  硬件交换:SR-IOV

kubelet,/etc/cni/net.d/

flannel:
支持多种后端:
  VxLAN
    (1) vxlan
    (2) Directrouting:各节点进行通信时,pod和pod之间只要节点的网络在同一个网段,pod和pod之间是通过直接路由(Directrouting)通信的,而不是通过叠加(underlay和overlay)方式通信。
  host-gw: Host Gateway
  UDP:

查看flannel配置文件

/etc/cni/net.d下会自动生成我们配置容器网络插件的一个配置文件供kubelet调用时使用;比如使用flannel插件:

cd /etc/cni/net.d/
cat 10-flannel.conflist

{
  "name": "cbr0",
  "cniVersion": "0.3.1",
  "plugins": [
    {
      "type": "flannel",
      "delegate": {
        "hairpinMode": true,
        "isDefaultGateway": true
      }
    },
    {
      "type": "portmap",
      "capabilities": {
        "portMappings": true
      }
    }
  ]
}

由于kubelet在每个节点运行pod,都需要控制docker运行pod里的容器,每个pod都需要分配IP,所以每个节点上都需要运行flannel插件(传统方式:运行为守护进程;kubeadm:在kube-system名称空间下使用daemonset控制器运行为pod),以便kubelet调用。

kubectl get pod -n kube-system # 图1
kubectl get daemonset -n kube-system # 图2

kubectl get configmap -n kube-system  # 图3

图1:

图2:

图3:

kubectl get configmap kube-flannel-cfg -o json -n kube-system

{
    "apiVersion": "v1",
    "data": {
        "cni-conf.json": "{\n  \"name\": \"cbr0\",\n  \"cniVersion\": \"0.3.1\",\n  \"plugins\": [\n    {\n      \"type\": \"flannel\",\n      \"delegate\": {\n        \"hairpinMode\": true,\n        \"isDefaultGateway\": true\n      }\n    },\n    {\n      \"type\": \"portmap\",\n      \"capabilities\": {\n        \"portMappings\": true\n      }\n    }\n  ]\n}\n",
        "net-conf.json": "{\n  \"Network\": \"10.244.0.0/16\",\n  \"Backend\": {\n    \"Type\": \"vxlan\"\n  }\n}\n"
    },
    "kind": "ConfigMap",
    "metadata": {
        "annotations": {
            "kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"data\":{\"cni-conf.json\":\"{\\n  \\\"name\\\": \\\"cbr0\\\",\\n  \\\"cniVersion\\\": \\\"0.3.1\\\",\\n  \\\"plugins\\\": [\\n    {\\n      \\\"type\\\": \\\"flannel\\\",\\n      \\\"delegate\\\": {\\n        \\\"hairpinMode\\\": true,\\n        \\\"isDefaultGateway\\\": true\\n      }\\n    },\\n    {\\n      \\\"type\\\": \\\"portmap\\\",\\n      \\\"capabilities\\\": {\\n        \\\"portMappings\\\": true\\n      }\\n    }\\n  ]\\n}\\n\",\"net-conf.json\":\"{\\n  \\\"Network\\\": \\\"10.244.0.0/16\\\",\\n  \\\"Backend\\\": {\\n    \\\"Type\\\": \\\"vxlan\\\"\\n  }\\n}\\n\"},\"kind\":\"ConfigMap\",\"metadata\":{\"annotations\":{},\"labels\":{\"app\":\"flannel\",\"tier\":\"node\"},\"name\":\"kube-flannel-cfg\",\"namespace\":\"kube-system\"}}\n"
        },
        "creationTimestamp": "2021-11-24T11:43:24Z",
        "labels": {
            "app": "flannel",
            "tier": "node"
        },
        "name": "kube-flannel-cfg",
        "namespace": "kube-system",
        "resourceVersion": "8934",
        "uid": "82f29971-a7eb-4f2f-80bd-44b24b75e388"
    }
}

flannel的配置参数:
Network:10.244.0.0/16 # 使用的CIDR格式的网络地址,用于为Pod配置网络功能。在每个节点上分配一个子网
	10.244.0.0/16 ->
       master:10.244.0.0/24
       woker01:10.244.1.0/24
       ...
       woker255:10.244.255.0/24
如果场景所需的node节点数量较大,而16位子网掩码只能分配256个子网段(256台node节点),可以换成8位子网掩码,但是一定不要忘记,别和service段 10.96.0.0/12位冲突
    10.0.0.0/8
      10.0.0.0/24
      ...
      10.255.255.0/24 

比如,我使用kubeadm安装的k8s集群,集群初始化的配置时可以修改这些参数配置信息:service、podSubnet # 如下图
  kubectl describe configmap kubeadm-config -n kube-system

SubnetLen: 把network切分子网供各节点使用时,使用多长的掩码进行切分,默认为24位;
SubnetMin: 10.244.10.0/24 限制节点可分配的子网地址段的最小值是多少
SubnetMax:10.244.100.0/24  限制节点可分配的子网地址段的最大值是多少
Backend:pod与pod之间通信方式,VxLAN(vxlan/Directrouting vxlan)/host-gw/udp
Type:vxlan  # flannel默认使用的网络类型是vxlan

 

calico网络策略

官方文档,获取calico详细介绍

curl https://docs.projectcalico.org/manifests/canal.yaml -O
kubectl apply -f canal.yaml

kubectl explain networkpolicy
KIND:     NetworkPolicy
VERSION:  networking.k8s.io/v1
apiVersion
kind
metadata
spec:
  egress	<[]Object> # 出站规则
    ports	<[]Object> # 目标端口(destination port)
      endPort	<integer> # 端口范围,与下面port字段组成端口范围,只要endport定义了,port就只能定义成端口号,且比endPort数字要小。
      port	<string> # 端口名称或者端口号
      protocol	<string> # 协议
    to	<[]Object> # 目标地址(destination address),选择以下三种情况的一种
      ipBlock	<Object> # 访问一个地址块(一个地址范围内的所有端点,可以pod ip、或者主机ip,只要在地址范围内)
        cidr	<string> -required- # 放行某个网段
        except	<[]string>   # 放行某个网段,但除了某个ip
      namespaceSelector	<Object> # 访问名称空间选择器中的pod,指定但为空,表示名称空间所有pod 
        matchExpressions	<[]Object> 
        matchLabels	<map[string]string>
      podSelector	<Object> # 访问pod标签选择器标出的pod,如果也设置了namespaceSelector,则选择 namespaceSelector指定的名称空间的pod,没指定的话,选择pod policy所在名称空间的pod。
        matchExpressions	<[]Object>
        matchLabels	<map[string]string>
  ingress	<[]Object> # 入站规则
    from	<[]Object> # 目标地址(destination address),哪些pod访问当前有一组pod
    ports	<[]Object> 

  podSelector	<Object> -required-
    matchExpressions	<[]Object>
    matchLabels	<map[string]string>
  policyTypes	<[]string> # ["Ingress"], ["Egress"], or ["Ingress", "Egress"],不指定的话,默认只要有egress或者ingress都生效。
	

1.入站规则限制

创建名称空间和ingress networkPolicy

[root@master01 networkPolicy]# vim ingress-def.yaml 
apiVersion: v1
kind: Namespace
metadata:
  name: dev

---
apiVersion: v1
kind: Namespace
metadata:
  name: prod

---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: deny-all-ingress
  # namespace: dev 
spec:
  podSelector: {} # 不指定任何pod选择器
  policyTypes:
  - Ingress  # 表示拒绝dev名称空间下所有入站请求

kubectl apply -f ingress-def.yaml -n dev

在dev名称空间下创建pod

[root@master01 networkPolicy]# vim pod-1.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod1
spec:
  containers:
  - name: myapp
    image: nginx:1.20       
# 在dev名称空间创建一个pod
[root@master01 networkPolicy]# kubectl apply -f pod-1.yaml -n dev
[root@master01 networkPolicy]# kubectl get po -n dev -o wide
NAME   READY   STATUS    RESTARTS   AGE   IP           NODE       NOMINATED NODE   READINESS GATES
pod1   1/1     Running   0          16s   10.244.2.3   worker02   <none>           <none>

# 请求10.244.2.3 pod的nginx 80端口,处在等待状态,一直没有响应。
curl 10.244.2.3

在prod名称空间下创建pod

[root@master01 networkPolicy]# kubectl apply -f pod-1.yaml -n prod
[root@master01 networkPolicy]# kubectl get po -n prod -o wide
NAME   READY   STATUS    RESTARTS   AGE   IP           NODE       NOMINATED NODE   READINESS GATES
pod1   1/1     Running   0          12s   10.244.1.3   worker01   <none>           <none>

# 请求10.244.1.3 pod的nginx 80端口响应其主页
curl 10.244.1.3

定义在dev名称空间中,入站时允许pod1被别人访问

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-all-ingress
  # namespace: dev 
spec:
  podSelector: {} 
  ingress: 
  - {} # 表示允许所有入站访问dev名称空间下的pod1
  policyTypes:
  - Ingress

kubectl apply -f ingress-def.yaml -n dev
kubectl get po -n dev -o wide
NAME   READY   STATUS    RESTARTS   AGE   IP           NODE       NOMINATED NODE   READINESS GATES
pod1   1/1     Running   0          34m   10.244.2.3   worker02   <none>           <none>

# 请求10.244.2.3 pod的nginx 80端口能响应其主页了
curl 10.244.2.3

在dev名称空间下,拥有标签app=myapp的pod,允许所有用户访问

kubectl label pod pod1 app=myapp -n dev

设置networkpolicy,放行特定的入站访问流量:

vim allow-netpol-demo.yaml 
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allow-myapp-ingress
spec:
  podSelector:
    matchLabels:
      app: myapp
  ingress:
  - from:
    - ipBlock:
        cidr: 10.244.0.0/16
        except:
        - 10.244.2.2/32
    ports:
    - protocol: TCP
      port: 80

kubectl apply -f allow-netpol-demo.yaml -n dev
curl 10.244.2.3 # 能正常请求主页
curl  10.244.2.3:443 # 因为443端口没有放行,所以curl请求会阻塞

添加如下两行,即可请求443端口:
    - protocol: TCP
      port: 80

再次curl 10.244.2.3:443,会报错:
curl: (7) Failed connect to 10.244.2.3:443; Connection refused
报错没问题,是因为我们443端口没被监听。但没被阻塞,是我们在ingress规则里放行了443

2.出站规则限制

限制所有出站的流量

kubectl create namespace prod
vim egress-def.yaml 

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: deny-all-egress
spec:
  podSelector: {}
  policyTypes:
  - Egress # Egress 拒绝所有出站的流量

[root@master01 networkPolicy]# kubectl apply -f egress-def.yaml -n prod

在prod名称空间中运行一个busybox pod,为了在其容器内部去访问外部

[root@master01 networkPolicy]# vim pod-busybox-2.yaml 
apiVersion: v1
kind: Pod
metadata:
  name: pod-busybox
spec:
  containers:
  - name: myapp
    image: busybox:latest
    command:
    - /bin/sh
    - -c
    - sleep 7200

[root@master01 networkPolicy]# kubectl get po -n prod -o wide
NAME        READY   STATUS    RESTARTS   AGE     IP       NODE   NOMINATED NODE   READINESS GATES
pod-busybox  1/1   Running   0       8m12s  10.244.1.5   worker01   <none>           <none>

在kube-system名称空间内寻找一个pod,给busybox pod访问

kubectl get po -n kube-system -o wide
coredns-7f6cbbb7b8-8rmk7  1/1  Running  4 (3h39m ago)   35d  10.244.0.3  master01   <none>  <none>

进入prod名称空间pod-busybox pod的busybox容器内,ping coredns pod

[root@master01 networkPolicy]# kubectl exec -it pod-busybox -n prod -- /bin/sh
/ # ping 10.244.0.3  # 如下图,无法ping通

允许prod名称空间所有pod出站

[root@master01 networkPolicy]# vim egress-def.yaml 
---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: deny-all-egress
  namespace: prod
spec:
  podSelector: {}
  egress:
  - {}
  policyTypes:
  - Egress

kubectl apply -f egress-def.yaml -n prod

[root@master01 networkPolicy]# kubectl exec -it pod-busybox -n prod -- /bin/sh
/ # ping 10.244.0.3 # 可以ping通
PING 10.244.0.3 (10.244.0.3): 56 data bytes
64 bytes from 10.244.0.3: seq=0 ttl=62 time=17.117 ms
64 bytes from 10.244.0.3: seq=1 ttl=62 time=8.963 ms

标签:10,插件,name,kubectl,网络,dev,10.244,pod,flannel
来源: https://www.cnblogs.com/zhangchaocoming/p/15772827.html