写在前面
学习k8s
遇到整理笔记博文内容主要涉及Kubernetes网络策略
理论简述K8s
中网络策略方式:egress
和ingress
的Demo
ipBlock
,namespaceSelector
,podSelector
的网络策略规则Demo
混吃等死,小富即安,飞黄腾达,是因为各有各的缘法,未必有高下之分。–—烽火戏诸侯《剑来》
Kubernetes网络策略
为了实现
细粒度的容器间网络访问隔离策略(防火墙)
,Kubernetes从1.3
版本开始,由SIG-Network
小组主导研发了Network Policy
机制,目前已升级为networking.k8s.io/v1
稳定版本。
Network Policy
的主要功能是对Pod
间的网络通信进行限制和准入控制
设置方式为将Pod的Label
作为查询条件,设置允许访问
或禁止访问
的客户端Pod列表
。查询条件可以作用于Pod
和Namespace
级别。
为了使用Network Policy
,Kubernetes
引入了一个新的资源对象NetworkPolicy
,供用户设置Pod间网络访问的策略
。但仅定义一个网络策略
是无法完成实际的网络隔离
的,还需要一个策略控制器(PolicyController)进行策略的实现
。
策略控制器由第三方网络组件提供,目前Calico, Cilium, Kube-router, Romana, Weave Net
等开源项目均支持网络策略的实现。Network Policy
的工作原理如图
policy controller
需要实现一个API Listener
,监听用户设置的NetworkPolicy
定义,并将网络访问规则通过各Node的Agent
进行实际设置(Agent
则需要通过CNI网络插件实现)
网络策略配置说明
网络策略
的设置主要用于对目标Pod
的网络访问进行限制,在默认·情况下对所有Pod都是允许访问
的,在设置了指向Pod的NetworkPolicy网络策略
之后,到Pod的访问才会被限制。需要注意的是网络策略是基于Pod的
ingress:定义允许访问目标Pod的入站白名单规则egress: 定义目标Pod允许访问的“出站”白名单规则NetWorkPolicy基于命名空间进行限制,即只作用当前命名空间,分为两种:
IP 策略命名空间策略pod选择器限制具体的规则限制方式分为三种(需要注意的是,多个限制之间是或的逻辑关系,如果希望变成与的关系,yaml文件需要配置为数组):
下面是一个资源文件的Demo
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policynamespace: defaultspec:podSelector: #用于定义该网络策略作用的Pod范围matchLabels:role: dbpolicyTypes: #网络策略的类型,包括ingress和egress两种- Ingress- Egressingress: #定义允许访问目标Pod的入站白名单规则- from: #满足from 条件的客户端才能访问ports定义的目标Pod端口号。- ipBlock: # IP限制cidr: 172.17.0.0/16except: #排除那些IP- 172.17.1.0/24- namespaceSelector: #命名空间限制matchLabels:project: myproject- podSelector: # pod选择器限制matchLabels:role: frontendports: #允许访问的目标Pod监听的端口号。- protocol: TCPport: 6379egress: #定义目标Pod允许访问的“出站”白名单规则- to: #目标Pod仅允许访问满足to条件的服务端IP范围和ports定义的端口号- ipBlock:cidr: 10.0.0.0/24ports: #允许访问的服务端的端口号。- protocol: TCPport: 5978
在Namespace级别设置默认的网络策略
在Namespace级别还可以设置一些默认的全局网络策略,以方便管理员对整个Namespace进行统一的网络策略设置。
默认拒绝所有入站流量
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: default-deny-ingressspec:podSelector: {}policyTypes:- Ingress
默认允许所有入站流量
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: allow-all-ingressspec:podSelector: {}ingress:- {}policyTypes:- Ingress
默认拒绝所有出站流量
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: default-deny-egressspec:podSelector: {}policyTypes:- Egress
默认允许所有出站流量
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: allow-all-egressspec:podSelector: {}egress:- {}policyTypes:- Egress
默认拒绝所有入口和所有出站流量
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: default-deny-allspec:podSelector: {}policyTypes:- Ingress- Egress
NetworkPolicy的发展
作为一个稳定特性,
SCTP
支持默认是被启用的。 要在集群层面禁用SCTP
,你(或你的集群管理员)需要为API
服务器指定--feature-gates=SCTPSupport=false
,… 来禁用SCTPSupport
特性门控。 启用该特性门控后,用户可以将NetworkPolicy
的protocol
字段设置为SCTP
(不同版本略有区别)
NetWorkPolicy实战
环境准备
先创建两个没有任何策略的SVC
┌──[root@vms81.liruilongs.github.io]-[~/ansible]└─$d=k8s-network-create┌──[root@vms81.liruilongs.github.io]-[~/ansible]└─$mkdir $d;cd $d┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl create ns liruilong-network-createnamespace/liruilong-network-create created┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl config set-context $(kubectl config current-context) --namespace=liruilong-network-createContext "kubernetes-admin@kubernetes" modified.┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl config view | grep namespacenamespace: liruilong-network-create┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$
我们先构造两个pod,为两个SVC提供能力
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl run pod1 --image=nginx --image-pull-policy=IfNotPresentpod/pod1 created┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl run pod2 --image=nginx --image-pull-policy=IfNotPresentpod/pod2 created┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get pods -o wideNAME READY STATUS RESTARTS AGE IPNODENOMINATED NODE READINESS GATESpod1 1/1Running 035s 10.244.70.31vms83.liruilongs.github.io <none> <none>pod2 1/1Running 021s 10.244.171.181 vms82.liruilongs.github.io <none> <none>┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$
然后我们分别修改pod中Ngixn容器主页
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get pods --show-labelsNAME READY STATUS RESTARTS AGE LABELSpod1 1/1Running 0100s run=pod1pod2 1/1Running 086s run=pod2┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl exec -it pod1 -- sh -c "echo pod1 >/usr/share/nginx/html/index.html"┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl exec -it pod2 -- sh -c "echo pod2 >/usr/share/nginx/html/index.html"
创建两个SVC
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl expose --name=svc1 pod pod1 --port=80 --type=LoadBalancerservice/svc1 exposed┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl expose --name=svc2 pod pod2 --port=80 --type=LoadBalancerservice/svc2 exposed┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get svcNAME TYPE CLUSTER-IP EXTERNAL-IPPORT(S) AGEsvc1 LoadBalancer 10.106.61.84192.168.26.240 80:30735/TCP 14ssvc2 LoadBalancer 10.111.123.194 192.168.26.241 80:31034/TCP 5s┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$
访问测试,无论在当前命名空间还是在指定命名空间,都可以相互访问
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl run testpod1 -it --rm --image=yauritux/busybox-curl --image-pull-policy=IfNotPresentIf you don''t see a command prompt, try pressing enter./home # curl svc1pod1/home # curl svc2pod2/home # exit
指定命名空间
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl run testpod2 -it --rm --image=yauritux/busybox-curl --image-pull-policy=IfNotPresent -n defaultIf you don''t see a command prompt, try pressing enter./home # curl svc1.liruilong-network-createpod1/home # curl svc2.liruilong-network-createpod2/home #
由于使用了LB,所以物理机也可以访问
PS E:\docker> curl 192.168.26.240 StatusCode : 200StatusDescription : OKContent : pod1RawContent : HTTP/1.1 200 OKConnection: keep-aliveAccept-Ranges: bytesContent-Length: 5Content-Type: text/htmlDate: Mon, 03 Jan 12:29:32 GMTETag: "61d27744-5"Last-Modified: Mon, 03 Jan 04:1...Forms : {}Headers : {[Connection, keep-alive], [Accept-Ranges, bytes], [Content-Length, 5], [Content-Type, text/html]...}Images : {}InputFields : {}Links : {}ParsedHtml : System.__ComObjectRawContentLength : 5
PS E:\docker> curl 192.168.26.241StatusCode : 200StatusDescription : OKContent : pod2RawContent : HTTP/1.1 200 OKConnection: keep-aliveAccept-Ranges: bytesContent-Length: 5Content-Type: text/htmlDate: Mon, 03 Jan 12:29:49 GMTETag: "61d27752-5"Last-Modified: Mon, 03 Jan 04:1...Forms : {}Headers : {[Connection, keep-alive], [Accept-Ranges, bytes], [Content-Length, 5], [Content-Type, text/html]...}Images : {}InputFields : {}Links : {}ParsedHtml : System.__ComObjectRawContentLength : 5PS E:\docker>
进入策略
下面我们看一下进入的策略
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get pods --show-labelsNAME READY STATUS RESTARTS AGE LABELSpod1 1/1Running 2 (3d12h ago) 5d9h run=pod1pod2 1/1Running 2 (3d12h ago) 5d9h run=pod2┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get svc -o wideNAME TYPE CLUSTER-IP EXTERNAL-IPPORT(S) AGE SELECTORsvc1 LoadBalancer 10.106.61.84192.168.26.240 80:30735/TCP 5d9h run=pod1svc2 LoadBalancer 10.111.123.194 192.168.26.241 80:31034/TCP 5d9h run=pod2┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$
测试的外部物理机机器IP
PS E:\docker> ipconfigWindows IP 配置..........以太网适配器 VMware Network Adapter VMnet8:连接特定的 DNS 后缀 . . . . . . . :本地链接 IPv6 地址. . . . . . . . : fe80::f9c8:e941:4deb:698f%24IPv4 地址 . . . . . . . . . . . . : 192.168.26.1子网掩码 . . . . . . . . . . . . : 255.255.255.0默认网关. . . . . . . . . . . . . :
IP限制
我们通过修改ip限制来演示网路策略,通过宿主机所在物理机访问。当设置指定网段可以访问,不是指定网段不可以访问
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$vim networkpolicy.yaml┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl apply -f working.k8s.io/test-network-policy configured
编写资源文件,允许172.17.0.0/16
网段的机器访问
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policynamespace: liruilong-network-createspec:podSelector:matchLabels:run: pod1policyTypes:- Ingressingress:- from:- ipBlock:cidr: 172.17.0.0/16 # 只允许这个网段访问ports:- protocol: TCPport: 80
集群外部机器无法访问
PS E:\docker> curl 192.168.26.240curl : 无法连接到远程服务器所在位置 行:1 字符: 1+ curl 192.168.26.240+ ~~~~~~~~~~~~~~~~~~~+ CategoryInfo: InvalidOperation: (.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest],WebException+ FullyQualifiedErrorId : WebCmdletWebResponseException,mands.InvokeWebRequestCommand
配置允许当前网段的ip访问
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policynamespace: liruilong-network-createspec:podSelector:matchLabels:run: pod1policyTypes:- Ingressingress:- from:- ipBlock:cidr: 192.168.26.0/24 # 只允许这个网段访问ports:- protocol: TCPport: 80
修改网段之后正常外部机器可以访问
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$sed -i 's#172.17.0.0/16#192.168.26.0/24#' networkpolicy.yaml┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl apply -f networkpolicy.yaml
测试,外部机器可以访问
PS E:\docker> curl 192.168.26.240StatusCode : 200StatusDescription : OKContent : pod1RawContent : HTTP/1.1 200 OKConnection: keep-aliveAccept-Ranges: bytesContent-Length: 5Content-Type: text/htmlDate: Sat, 08 Jan 14:59:13 GMTETag: "61d9a663-5"Last-Modified: Sat, 08 Jan 14:5...Forms : {}Headers : {[Connection, keep-alive], [Accept-Ranges, bytes], [Content-Length, 5], [Content-Type, text/html]...}Images : {}InputFields : {}Links : {}ParsedHtml : System.__ComObjectRawContentLength : 5
命名空间限制
设置只允许default命名空间的数据通过
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get ns --show-labels | grep defaultdefault Active 26dkubernetes.io/metadata.name=default┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$vim networkpolicy-name.yaml┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl apply -f networkpolicy-working.k8s.io/test-network-policy configured
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policynamespace: liruilong-network-createspec:podSelector:matchLabels:run: pod1policyTypes:- Ingressingress:- from:- namespaceSelector:matchLabels:kubernetes.io/metadata.name: defaultports:- protocol: TCPport: 80
宿主机所在物理机无法访问访问
PS E:\docker> curl 192.168.26.240curl : 无法连接到远程服务器所在位置 行:1 字符: 1+ curl 192.168.26.240+ ~~~~~~~~~~~~~~~~~~~+ CategoryInfo: InvalidOperation: (.HttpWebRequest:HttpWebRequest) [Invoke-WebRequest],WebException+ FullyQualifiedErrorId : WebCmdletWebResponseException,mands.InvokeWebRequestCommandPS E:\docker>
当前命名空间也无法访问
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl run testpod1 -it --rm --image=yauritux/busybox-curl --image-pull-policy=IfNotPresent/home # curl --connect-timeout 10 -m 10 svc1curl: (28) Connection timed out after 10413 milliseconds
default命名空间可以访问
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl run testpod1 -it --rm --image=yauritux/busybox-curl --image-pull-policy=IfNotPresent --namespace=default/home # curl --connect-timeout 10 -m 10 svc1.liruilong-network-createpod1/home #
pod选择器限制
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policynamespace: liruilong-network-createspec:podSelector:matchLabels:run: pod1policyTypes:- Ingressingress:- from:- podSelector:matchLabels:run: testpodports:- protocol: TCPport: 80
创建一个策略,只允许标签为run=testpod
的pod访问
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl apply -f networkpolicy-working.k8s.io/test-network-policy created
创建两个pod,都设置--labels=run=testpod
标签,只有当前命名空间可以访问
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl run testpod1 -it --rm --image=yauritux/busybox-curl --image-pull-policy=IfNotPresent --labels=run=testpod --namespace=default/home # curl --connect-timeout 10 -m 10 svc1.liruilong-network-createcurl: (28) Connection timed out after 10697 milliseconds
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl run testpod1 -it --rm --image=yauritux/busybox-curl --image-pull-policy=IfNotPresent --labels=run=testpod/home # curl --connect-timeout 10 -m 10 svc1pod1/home #
下面的设置可以其他所有命名空间可以访问
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policynamespace: liruilong-network-createspec:podSelector:matchLabels:run: pod1policyTypes:- Ingressingress:- from:- podSelector:matchLabels:podSelector:matchLabels:run: testpodports:- protocol: TCPport: 80
default 命名空间和当前命名空间可以访问
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policynamespace: liruilong-network-createspec:podSelector:matchLabels:run: pod1policyTypes:- Ingressingress:- from:- podSelector:matchLabels:kubernetes.io/metadata.name: defaultpodSelector:matchLabels:run: testpod- podSelector:matchLabels:run: testpodports:- protocol: TCPport: 80
定位pod所使用的网络策略
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get networkpoliciesNAME POD-SELECTOR AGEtest-network-policy run=pod1 13m┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get pods --show-labelsNAME READY STATUS RESTARTS AGELABELSpod1 1/1Running 2 (3d15h ago) 5d12h run=pod1pod2 1/1Running 2 (3d15h ago) 5d12h run=pod2┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get networkpolicies | grep run=pod1test-network-policy run=pod1 15m┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$
出去策略
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policyspec:podSelector:matchLabels:run: pod1policyTypes:- Egressegress:- to:- podSelector:matchLabels:run: pod2ports:- protocol: TCPport: 80
pod1只能访问pod2的TCP协议80端口
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl apply -f networkpolicy1.yaml
通过IP访问正常pod2
┌──[root@vms81.liruilongs.github.io]-[~]└─$kubectl exec -it pod1 -- bashroot@pod1:/# curl 10.111.123.194pod2
因为DNS的pod在另一个命名空间(kube-system)运行,pod1只能到pod2,所以无法通过域名访问,需要添加另一个命名空间
┌──[root@vms81.liruilongs.github.io]-[~]└─$kubectl exec -it pod1 -- bashroot@pod1:/# curl svc2^C
相关参数获取
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get ns --show-labels | grep kube-systemkube-system Active 27dkubernetes.io/metadata.name=kube-system┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get pods --show-labels -n kube-system | grep dnscoredns-7f6cbbb7b8-ncd2s 1/1Running 13 (3d19h ago) 24d k8s-app=kube-dns,pod-template-hash=7f6cbbb7b8coredns-7f6cbbb7b8-pjnct 1/1Running 13 (3d19h ago) 24d k8s-app=kube-dns,pod-template-hash=7f6cbbb7b8
配置两个出去规则,一个到pod2,一个到kube-dns,使用不同端口协议
apiVersion: networking.k8s.io/v1kind: NetworkPolicymetadata:name: test-network-policyspec:podSelector:matchLabels:run: pod1policyTypes:- Egressegress:- to:- podSelector:matchLabels:run: pod2ports:- protocol: TCPport: 80- to:- namespaceSelector:matchLabels:kubernetes.io/metadata.name: kube-systempodSelector:matchLabels:k8s-app: kube-dnsports:- protocol: UDPport: 53
测试可以通过域名访问
┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$vim networkpolicy2.yaml┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl apply -f working.k8s.io/test-network-policy configured┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl get networkpoliciesNAME POD-SELECTOR AGEtest-network-policy run=pod1 3h38m┌──[root@vms81.liruilongs.github.io]-[~/ansible/k8s-network-create]└─$kubectl exec -it pod1 -- bashroot@pod1:/# curl svc2pod2root@pod1:/#
时间关系,关于网络策略和小伙伴们分享到这里,生活加油