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k8s 网络策略

k8s网络 策略
2023-09-11 14:20:30 时间

1、networkpolicy

networkpolicy是K8S API中标准的资源类型，是定义在一组POD资源上的控制进（Ingress）出（Egress）POD流量的规则

networkpolicy资源中重要概念：

POD组：podSelector通过matchLabel或者matchExpression的标签选择器选择的POD集合，即策略将在哪些POD上生效

Ingress：进入POD的流量策略，可以定义源端点（spec.ingress.from）和目标端口(spec.ingress.ports)

Egress：出POD的流量策略,可以定义目标端点（spec.egress.to）和目标端口(spec.egress.ports)

端点(to,from)： 可以通过nameSpace或者ipBlock 来定义

1.1、实验

namespace：demov10

kind: Namespace
apiVersion: v1
metadata:
  name: demov10
  namespace: demov10
  labels:
    project: demov10

---
kind: Service
apiVersion: v1
metadata:
  name: demov10
  namespace: demov10
spec:
  selector:
    app: demov10
  ports:
  - name: demov10
    port: 80
    targetPort: 80
    protocol: TCP
---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: demov10
  namespace: demov10
spec:
  replicas: 2
  selector:
    matchLabels:
      app: demov10
  template:
    metadata:
      name: demov10
      namespace: demov10
      labels:
        app: demov10
    spec:
      containers:
      - name: demov10
        image: ikubernetes/demoapp:v1.0
        imagePullPolicy: Always
        ports:
        - name: demov10
          containerPort: 80
          protocol: TCP
        resources:
          limits:
            cpu: 100m
            memory: 100Mi
          requests:
            cpu: 50m
            memory: 50Mi
View Code

namespace：demov11

kind: Namespace
apiVersion: v1
metadata:
  name: demov11
  namespace: demov11
  labels:
    project: demov11

---
kind: Service
apiVersion: v1
metadata:
  name: demov11
  namespace: demov11
spec:
  selector:
    app: demov11
  ports:
  - name: demov11
    port: 80
    targetPort: 80
    protocol: TCP
---
kind: Deployment
apiVersion: apps/v1
metadata:
  name: demov11
  namespace: demov11
spec:
  replicas: 2
  selector:
    matchLabels:
      app: demov11
  template:
    metadata:
      name: demov11
      namespace: demov11
      labels:
        app: demov11
    spec:
      containers:
      - name: demov11
        image: ikubernetes/demoapp:v1.1
        imagePullPolicy: Always
        ports:
        - name: demov11
          containerPort: 80
          protocol: TCP
        resources:
          limits:
            cpu: 100m
            memory: 100Mi
          requests:
            cpu: 50m
            memory: 50Mi
View Code

1.1.1、设置策略使demov10名称空间下的POD，

ingress：只能本名称空间下的pod才能访问

egress：能够访问外网

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: allown
  namespace: demov10
spec:
  podSelector:    #根据标签选择POD
    matchLabels:
      app: demov10      
  policyTypes: ["Ingress","Egress"]
  ingress:
#  - from:
#    - namespaceSelector:
#        matchLabels:
#          project: demov10
#    - ipBlock:
#        cidr: 10.200.0.0/24
  - from:
    - namespaceSelector:
        matchExpressions:
        - key: project
          operator: In
          values: ["demov10"]   #只允许本名称空间的POD的流量进入POD
    ports:
    - protocol: TCP
      port: 80    #只对外开放80端口

    
  egress:
  - to:
    - namespaceSelector:
        matchExpressions:
        - key: project
          operator: In
          values: ["demov10"]     #允许访问本名称空间下的POD

    - ipBlock:   
        except:
        - 10.200.0.0/16   #拒绝访问集群POD网段
        cidr: 0.0.0.0/0     
  - to:
    - ipBlock:
        cidr: 10.200.0.0/16
    ports:
    - protocol: UDP
      port: 53     #放通POD网段的DNS服务
View Code

验证：

demov10：

demov11：

从demov11下的POD访问demov10POD：都无法访问

节点上也无法访问：

1.2、隔离名称空间

一般各个名称空间应当相互隔离，但是通常应当允许内部POD以及来自集群上管理类应用专用名称空间的请求（如：kube-system，kubernetes-dashbord等）和DNS服务等。如给demov10建立一个默认策略：

apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: default                    #策略名称
  namespace: demov10       #生效名称空间
spec:
  podSelector: {}                    #生效的pod，{}表示所有
  policyTypes: ["Ingress","Egress"]     #类型
  ingress:   #进站流量
  - from:
    - namespaceSelector:                        
        matchExpressions:
        - key: kubernetes.io/metadata.name
          operator: In
          values: [demov10,demov11,kube-system,logs,monitoring,kubernetes-dashboard]
  egress:  #出站流量
  - to:
    - namespaceSelector:
        matchExpressions:
        - key: kubernetes.io/metadata.name
          operator: In
          values: ["demov10"] 
  - to:
    ports:
    - protocol: UDP
      port: 53
  - to:   #到apiserver
    - ipBlock:
        cidr: 10.0.2.200/32 
    ports:
    - protocol: TCP
      port: 6443
 
 

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