kubernetes集群应用 service进阶
发布时间：2023年12月21日
kubernetes集群应用 Service进阶
一、场景
使用kubernetes集群运行工作负载时，由于Pod经常处于用后即焚状态，Pod对应的IP地址也会经常变化，因此我们不能直接访问Pod，可以通过Service对应的端点列表（Endpoints）实现对Pod IP跟踪，进而实现通过Service访问Pod目的。
二、学习目标
- 掌握service三种代理模式
- 了解Service类型
- 了解Service参数
- 掌握Service创建方法
- 了解sessionAffinity配置方法
- 掌握修改为ipvs调度方式的方法
- 掌握DNS应用验证
三、学习步骤
| 序号 | 步骤 | 备注 |
|---|---|---|
| 1 | service三种代理模式 | |
| 2 | Service类型 | |
| 3 | Service参数 | |
| 4 | Service创建方法 | |
| 5 | sessionAffinity类型 | |
| 6 | 修改为IPVS调度方式的方法 | |
| 7 | DNS应用验证 |
四、课程内容
4.1 service三种代理模式
-
kubernetes集群中有三层网络，一类是真实存在的，例如Node Network、Pod Network,提供真实IP地址;一类是虚拟的，例如Cluster Network或Service Network，提供虚拟IP地址，不会出现在接口上，仅会出现在Service当中
-
kube-proxy始终watch（监控）kube-apiserver上关于Service相关的资源变动状态，一旦获取相关信息kube-proxy都要把相关信息转化为当前节点之上的，能够实现Service资源调度到特定Pod之上的规则，近而实现访问Service就能够获取Pod所提供的服务
-
Service三种代理模式：UserSpace(用户空间)、内核空间Iptables、内核空间Ipvs
4.1.1 UserSpace
客户端访问Service时，由内核空间Service转发给当前节点用户空间kube-proxy代理后，再转给内核空间Service（iptables规则）进行分发，实现访问与Service关联的Pod，此种工作方式需要在用户空间与内核空间进行二次转化，效率低。
4.1.2 内核空间iptables
客户端直接访问本地内核中的Service IP，由内核Iptables规则直接进行调度，直接转发到Pod。
4.1.3 内核空间ipvs
客户端直接访问本地内核中的Service IP，由内核ipvs规则直接进行调度，直接转发到Pod。
4.1.4 iptables与ipvs对比
-
iptables
-
工作在内核空间
-
优点
-
灵活，功能强大（可以在数据包不同阶段对包进行操作）
-
-
缺点
-
表中规则过多时，响应变慢
-
-
-
ipvs
-
工作在内核空间
-
优点
-
转发效率高
-
调度算法丰富：rr，wrr，lc，wlc，ip hash...
-
-
缺点
-
内核支持不全,低版本内核不能使用，需要升级到4.0或5.0以上。
-
-
-
使用iptables与ipvs时机
-
1.10版本之前使用iptables(1.1版本之前使用UserSpace进行转发)
-
1.11版本之后同时支持iptables与ipvs，默认使用ipvs，如果ipvs模块没有加载时，会自动降级至iptables
-
4.2 service类型
Service类型决定了访问Service的方法
4.2.1 service类型分类
-
ClusterIP
-
默认，分配一个集群内部可以访问的虚拟IP
-
-
NodePort
-
在每个Node上分配一个端口作为外部访问入口
-
nodePort端口范围为:30000-32767
-
-
LoadBalancer
-
工作在特定的Cloud Provider上，例如Google Cloud，AWS，OpenStack
-
-
ExternalName
-
表示把集群外部的服务引入到集群内部中来，即实现了集群内部pod和集群外部的服务进行通信
-
4.2.2 Service参数
-
port 访问service使用的端口
-
targetPort Pod中容器端口
-
nodePort 通过Node实现外网用户访问k8s集群内service (30000-32767)
4.3 Service创建
Service的创建在工作中有两种方式，一是命令行创建，二是通过资源清单文件YAML文件创建。
4.3.1 ClusterIP类型
ClusterIP根据是否生成ClusterIP又可分为普通Service和Headless Service
Service两类：
-
普通Service:
为Kubernetes的Service分配一个集群内部可访问的固定虚拟IP(Cluster IP), 实现集群内的访问。
-
Headless Service:
该服务不会分配Cluster IP, 也不通过kube-proxy做反向代理和负载均衡。而是通过DNS提供稳定的网络ID来访问，DNS会将headless service的后端直接解析为podIP列表。
4.3.1.1 普通ClusterIP Service创建
4.3.1.1.1 命令行创建Service
-
创建Deployment类型的应用
[root@master01 ~]# cat 01_create_deployment_app_nginx.yaml apiVersion: apps/v1 kind: Deployment metadata: ?name: nginx-server1 spec: ?replicas: 2 ?selector: ? ?matchLabels: ? ? ?app: nginx ?template: ? ? metadata: ? ? ? labels: ? ? ? ? app: nginx ? ? spec: ? ? ? containers: ? ? ? - name: c1 ? ? ? ? image: harbor.wego.red/library/nginx:1.9.0 ? ? ? ? imagePullPolicy: IfNotPresent ? ? ? ? ports: ? ? ? ? - containerPort: 80
-
应用资源清单文件
[root@master01 ~]# kubectl apply -f 01_create_deployment_app_nginx.yaml
-
验证Deployment类型的创建情况
[root@master01 ~]# kubectl get deployment.apps NAME ? ? ? ? ? ?READY ? UP-TO-DATE ? AVAILABLE ? AGE nginx-server1 ? 2/2 ? ? 2 ? ? ? ? ? ?2 ? ? ? ? ? 13s
-
创建ClusterIP类型service与Deployment类型应用关联
命令创建service [root@master01 ~]# kubectl expose deployment.apps nginx-server1 --type=ClusterIP --target-port=80 --port=80 ? 输出 service/nginx-server1 exposed ? 说明 expose 创建service deployment.apps 控制器类型 nginx-server1 应用名称，也是service名称 --type=ClusterIP 指定service类型 --target-port=80 指定Pod中容器端口 --port=80 指定service端口
4.3.1.1.2 通过资源清单文件创建Service
[root@master01 ~]# cat 02_create_deployment_app_nginx_with_service.yaml apiVersion: apps/v1 kind: Deployment metadata: ?name: nginx-server1 spec: ?replicas: 2 ?selector: ? ?matchLabels: ? ? ?app: nginx ?template: ? ? metadata: ? ? ? labels: ? ? ? ? app: nginx ? ? spec: ? ? ? containers: ? ? ? - name: nginx-smart ? ? ? ? image: harbor.wego.red/library/nginx:1.9.0 ? ? ? ? imagePullPolicy: IfNotPresent ? ? ? ? ports: ? ? ? ? - containerPort: 80 --- apiVersion: v1 kind: Service metadata: ?name: nginx-svc spec: ?type: ClusterIP ?ports: ?- protocol: TCP ? ?port: 80 ? ?targetPort: 80 ?selector: ? ?app: nginx ?
[root@master01 ~]# kubectl apply -f 02_create_deployment_app_nginx_with_service.yaml
-
验证
查看service [root@master01 ~]# kubectl get service NAME ? ? ? ? TYPE ? ? ? ?CLUSTER-IP ? ? ? EXTERNAL-IP ? PORT(S) ? ?AGE kubernetes ? ClusterIP ? 10.96.0.1 ? ? ? ?<none> ? ? ? ?443/TCP ? ?4d15h nginx-svc ? ?ClusterIP ? 10.101.153.50 ? <none> ? ? ? ?80/TCP ? ?3s
查看endpoints [root@master01 ~]# kubectl get endpoints NAME ? ? ? ? ENDPOINTS ? ? ? ? ? ? ? ? ? ? ? ? ? ?AGE kubernetes ? 192.168.122.30:6443 ? ? ? ? ? ? ? ? ?4d15h nginx-svc ? ?172.16.189.74:80,172.16.235.150:80 ? 8s
查看Pod [root@master01 ~]# kubectl get pods -l app=nginx NAME READY STATUS RESTARTS AGE nginx-server1-77d4c485d8-gsrmq 1/1 Running 0 12s nginx-server1-77d4c485d8-mmc52 1/1 Running 0 12s
4.3.1.1.3 访问
[root@master01 ~]# curl http://10.101.153.50:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
4.3.1.1.4 两个pod里做成不同的主页方便测试负载均衡
[root@master01 ~]# kubectl exec -it nginx-server1-77d4c485d8-gsrmq -- /bin/bash root@deployment-nginx-6fcfb67547-nv7dn:/# cd /usr/share/nginx/html/ root@deployment-nginx-6fcfb67547-nv7dn:/usr/share/nginx/html# echo web1 > index.html root@deployment-nginx-6fcfb67547-nv7dn:/usr/share/nginx/html# exit exit
[root@master01 ~]# kubectl exec -it nginx-server1-77d4c485d8-mmc52 -- /bin/bash root@deployment-nginx-6fcfb67547-rqrcw:/# cd /usr/share/nginx/html/ root@deployment-nginx-6fcfb67547-rqrcw:/usr/share/nginx/html# echo web2 > index.html root@deployment-nginx-6fcfb67547-rqrcw:/usr/share/nginx/html# exit exit
4.3.1.1.5 测试
[root@master01 ~]# curl 10.101.153.50 或 [root@master01 ~]# while true;do curl 10.101.153.50;sleep 1; done
4.3.1.2 Headless Service
普通的ClusterIP service是service name解析为cluster ip,然后cluster ip对应到后面的pod ip,而无头service是指service name 直接解析为后面的pod ip
4.3.1.2.1 编写用于创建Deployment控制器类型的资源清单文件
[root@master01 ~]# cat 03_create_deployment_app_nginx.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-server1
spec:
replicas: 2
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx-smart
image: harbor.wego.red/library/nginx:1.9.0
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
4.3.1.2.2 通过资源清单文件创建headless Service
编写YAML文件
命令
[root@master ~]# vim 04_headless-service.yml
apiVersion: v1
kind: Service
metadata:
name: headless-service
namespace: default
spec:
type: ClusterIP # ClusterIP类型,也是默认类型
clusterIP: None # None就代表是无头service
ports: # 指定service 端口及容器端口
- port: 80 # service ip中的端口
protocol: TCP
targetPort: 80 # pod中的端口
selector: # 指定后端pod标签
app: nginx # 可通过kubectl get pod -l app=nginx查看哪些pod在使用此标签
4.3.1.2.3 应用资源清单文件创建headless Service
命令 [root@master ~]# kubectl apply -f 04_headless_service.yml 输出 service/headless-service created
4.3.1.2.4 查看已创建的headless Service
命令 [root@master ~]# kubectl get svc 输出 NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE headless-service ClusterIP None <none> 80/TCP 2m18s kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 5d9h 可以看到headless-service没有CLUSTER-IP,用None表示
4.3.1.2.5 DNS
DNS服务监视Kubernetes API,为每一个Service创建DNS记录用于域名解析
headless service需要DNS来解决访问问题
DNS记录格式为: <service-name>.<namespace-name>.svc.cluster.local.
4.3.1.2.5.1 查看kube-dns服务的IP
命令 [root@master1 ~]# kubectl get svc -n kube-system 输出 NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 5d9h metrics-server ClusterIP 10.105.219.44 <none> 443/TCP 45h 查看到coreDNS的服务地址是10.96.0.10
4.3.1.2.5.2 在集群主机通过DNS服务地址查找无头服务的dns解析
命令 [root@master01 ~]# dig -t A headless-service.default.svc.cluster.local. @10.96.0.10 输出 ; <<>> DiG 9.11.4-P2-RedHat-9.11.4-16.P2.el7_8.2 <<>> -t A headless-service.default.svc.cluster.local. @10.96.0.10 ;; global options: +cmd ;; Got answer: ;; WARNING: .local is reserved for Multicast DNS ;; You are currently testing what happens when an mDNS query is leaked to DNS ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 31371 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;headless-service.default.svc.cluster.local. IN A #被解析域名 ;; ANSWER SECTION: headless-service.default.svc.cluster.local. 30 IN A 10.224.235.147 #注意这里IP ;; Query time: 0 msec ;; SERVER: 10.96.0.10#53(10.96.0.10) ;; WHEN: Sun May 17 10:58:50 CST 2020 ;; MSG SIZE rcvd: 129
4.3.1.2.5.3 验证pod的IP
命令 [root@master ~]# kubectl get pod -o wide 输出 NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES nginx-deployment-56bf6c9c8c-jmk7r 1/1 Running 0 35m 10.224.235.147 worker1 <none> <none>
4.3.1.2.5.4 在集群中创建一个pod验证
创建一个镜像为busyboxplus:curl的pod，pod名称为bb2,用来解析域名
命令
[root@master01 ~]# kubectl run bbp --image=busyboxplus:curl -it
输出
If you don't see a command prompt, try pressing enter.
解析域名
命令
[ root@bbp:/ ]$ curl http://headless-service.default.svc.cluster.local.
输出
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
[ root@bbp:/ ]$ exit
Session ended, resume using 'kubectl attach bbp -c bbp -i -t' command when the pod is running
4.3.2 NodePort类型
-
创建资源清单文件
[root@master01 ~]# cat 05_create_nodeport_service_app.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-app
labels:
app: nginx-app
spec:
replicas: 2
selector:
matchLabels:
app: nginx-app
template:
metadata:
labels:
app: nginx-app
spec:
containers:
- name: c1
image: harbor.wego.red/library/nginx:1.9.0
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx-app
spec:
type: NodePort
selector:
app: nginx-app
ports:
- protocol: TCP
nodePort: 30001
port: 8060
targetPort: 80
-
应用资源清单文件
[root@master01 ~]# kubectl apply -f 05_create_nodeport_service_app.yaml deployment.apps/nginx-app created service/nginx-app created
-
验证service创建
[root@master01 ~]# kubectl get deployment.apps
NAME READY UP-TO-DATE AVAILABLE AGE
nginx-app 2/2 2 2 26s
[root@master01 ~]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2d22h
nginx-app NodePort 10.104.157.20 <none> 8060:30001/TCP 36s
[root@master01 ~]# kubectl get endpoints
NAME ENDPOINTS AGE
kubernetes 192.168.122.10:6443 2d22h
nginx-app 172.16.1.24:80,172.16.2.20:80 2m10s
[root@master01 ~]# ss -anput | grep ":30001"
tcp LISTEN 0 128 :::30001 :::* users:(("kube-proxy",pid=5826,fd=9))
[root@worker01 ~]# ss -anput | grep ":30001"
tcp LISTEN 0 128 :::30001 :::* users:(("kube-proxy",pid=4937,fd=11))
[root@worker02 ~]# ss -anput | grep ":30001"
tcp LISTEN 0 128 :::30001 :::* users:(("kube-proxy",pid=5253,fd=11))
[root@master01 ~]# kubectl get pods NAME READY STATUS RESTARTS AGE nginx-app-ffd5ccc78-cnwbx 1/1 Running 0 8m59s nginx-app-ffd5ccc78-mz77g 1/1 Running 0 8m59s [root@master01 ~]# kubectl exec -it nginx-app-ffd5ccc78-cnwbx -- bash root@nginx-app-ffd5ccc78-cnwbx:/# echo "nginx-app-1" > /usr/share/nginx/html/index.html root@nginx-app-ffd5ccc78-cnwbx:/# exit exit [root@master01 ~]# kubectl exec -it nginx-app-ffd5ccc78-mz77g -- bash root@nginx-app-ffd5ccc78-mz77g:/# echo "nginx-app-2" > /usr/share/nginx/html/index.html root@nginx-app-ffd5ccc78-mz77g:/# exit exit
-
在与kubernetes 节点同一网络主机中访问k8s集群内service
[root@bogon ~]# curl http://192.168.122.11:30001 nginx-app-2 [root@bogon ~]# curl http://192.168.122.21:30001 nginx-app-1 [root@bogon ~]# curl http://192.168.122.22:30001 nginx-app-1 [root@bogon ~]# curl http://192.168.122.23:30001 nginx-app-2
4.3.3 LoadBalancer
4.3.3.1 集群外访问过程
-
用户
-
域名
-
云服务提供商提供LB服务
-
NodeIP:Port(service IP)
-
Pod IP：端口
4.3.3.2 自建Kubernetes的LoadBalancer类型服务方案-MetalLB
MetalLB可以为kubernetes集群中的Service提供网络负载均衡功能。
MetalLB两大功能为:
-
地址分配，类似于DHCP
-
外部通告，一旦MetalLB为服务分配了外部IP地址，它就需要使群集之外的网络意识到该IP在群集中“存在”。MetalLB使用标准路由协议来实现此目的：ARP，NDP或BGP。
4.3.3.2.1 拉取镜像
# docker pull metallb/speaker:v0.9.3 # docker pull metallb/controller:v0.9.3
4.3.3.2.2 参考资料
参考网址： https://metallb.universe.tf/installation/ 资源清单文件下载： # kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.3/manifests/namespace.yaml # kubectl apply -f https://raw.githubusercontent.com/metallb/metallb/v0.9.3/manifests/metallb.yaml # On first install only # kubectl create secret generic -n metallb-system memberlist --from-literal=secretkey="$(openssl rand -base64 128)"
4.3.3.2.3 资源清单及其应用
创建namespace
查看文件内容
[root@nginx metallb]# cat namespace.yaml
apiVersion: v1
kind: Namespace
metadata:
name: metallb-system
labels:
app: metallb
在master01应用资源清单文件
[root@master01 ~]# kubectl apply -f http://nginx.wego.red/service/metallb/namespace.yaml
创建metallb
查看内容
[root@nginx metallb]# cat metallb.yaml
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
labels:
app: metallb
name: controller
namespace: metallb-system
spec:
allowPrivilegeEscalation: false
allowedCapabilities: []
allowedHostPaths: []
defaultAddCapabilities: []
defaultAllowPrivilegeEscalation: false
fsGroup:
ranges:
- max: 65535
min: 1
rule: MustRunAs
hostIPC: false
hostNetwork: false
hostPID: false
privileged: false
readOnlyRootFilesystem: true
requiredDropCapabilities:
- ALL
runAsUser:
ranges:
- max: 65535
min: 1
rule: MustRunAs
seLinux:
rule: RunAsAny
supplementalGroups:
ranges:
- max: 65535
min: 1
rule: MustRunAs
volumes:
- configMap
- secret
- emptyDir
---
apiVersion: policy/v1beta1
kind: PodSecurityPolicy
metadata:
labels:
app: metallb
name: speaker
namespace: metallb-system
spec:
allowPrivilegeEscalation: false
allowedCapabilities:
- NET_ADMIN
- NET_RAW
- SYS_ADMIN
allowedHostPaths: []
defaultAddCapabilities: []
defaultAllowPrivilegeEscalation: false
fsGroup:
rule: RunAsAny
hostIPC: false
hostNetwork: true
hostPID: false
hostPorts:
- max: 7472
min: 7472
privileged: true
readOnlyRootFilesystem: true
requiredDropCapabilities:
- ALL
runAsUser:
rule: RunAsAny
seLinux:
rule: RunAsAny
supplementalGroups:
rule: RunAsAny
volumes:
- configMap
- secret
- emptyDir
---
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
app: metallb
name: controller
namespace: metallb-system
---
apiVersion: v1
kind: ServiceAccount
metadata:
labels:
app: metallb
name: speaker
namespace: metallb-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
app: metallb
name: metallb-system:controller
rules:
- apiGroups:
- ''
resources:
- services
verbs:
- get
- list
- watch
- update
- apiGroups:
- ''
resources:
- services/status
verbs:
- update
- apiGroups:
- ''
resources:
- events
verbs:
- create
- patch
- apiGroups:
- policy
resourceNames:
- controller
resources:
- podsecuritypolicies
verbs:
- use
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
labels:
app: metallb
name: metallb-system:speaker
rules:
- apiGroups:
- ''
resources:
- services
- endpoints
- nodes
verbs:
- get
- list
- watch
- apiGroups:
- ''
resources:
- events
verbs:
- create
- patch
- apiGroups:
- policy
resourceNames:
- speaker
resources:
- podsecuritypolicies
verbs:
- use
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
labels:
app: metallb
name: config-watcher
namespace: metallb-system
rules:
- apiGroups:
- ''
resources:
- configmaps
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
labels:
app: metallb
name: pod-lister
namespace: metallb-system
rules:
- apiGroups:
- ''
resources:
- pods
verbs:
- list
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
app: metallb
name: metallb-system:controller
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: metallb-system:controller
subjects:
- kind: ServiceAccount
name: controller
namespace: metallb-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
labels:
app: metallb
name: metallb-system:speaker
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: metallb-system:speaker
subjects:
- kind: ServiceAccount
name: speaker
namespace: metallb-system
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
labels:
app: metallb
name: config-watcher
namespace: metallb-system
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: config-watcher
subjects:
- kind: ServiceAccount
name: controller
- kind: ServiceAccount
name: speaker
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
labels:
app: metallb
name: pod-lister
namespace: metallb-system
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: pod-lister
subjects:
- kind: ServiceAccount
name: speaker
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
labels:
app: metallb
component: speaker
name: speaker
namespace: metallb-system
spec:
selector:
matchLabels:
app: metallb
component: speaker
template:
metadata:
annotations:
prometheus.io/port: '7472'
prometheus.io/scrape: 'true'
labels:
app: metallb
component: speaker
spec:
containers:
- args:
- --port=7472
- --config=config
env:
- name: METALLB_NODE_NAME
valueFrom:
fieldRef:
fieldPath: spec.nodeName
- name: METALLB_HOST
valueFrom:
fieldRef:
fieldPath: status.hostIP
- name: METALLB_ML_BIND_ADDR
valueFrom:
fieldRef:
fieldPath: status.podIP
- name: METALLB_ML_LABELS
value: "app=metallb,component=speaker"
- name: METALLB_ML_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
- name: METALLB_ML_SECRET_KEY
valueFrom:
secretKeyRef:
name: memberlist
key: secretkey
image: harbor.wego.red/library/metallb/speaker:v0.9.3 修改
imagePullPolicy: Always
name: speaker
ports:
- containerPort: 7472
name: monitoring
resources:
limits:
cpu: 100m
memory: 100Mi
securityContext:
allowPrivilegeEscalation: false
capabilities:
add:
- NET_ADMIN
- NET_RAW
- SYS_ADMIN
drop:
- ALL
readOnlyRootFilesystem: true
hostNetwork: true
nodeSelector:
beta.kubernetes.io/os: linux
serviceAccountName: speaker
terminationGracePeriodSeconds: 2
tolerations:
- effect: NoSchedule
key: node-role.kubernetes.io/master
---
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: metallb
component: controller
name: controller
namespace: metallb-system
spec:
revisionHistoryLimit: 3
selector:
matchLabels:
app: metallb
component: controller
template:
metadata:
annotations:
prometheus.io/port: '7472'
prometheus.io/scrape: 'true'
labels:
app: metallb
component: controller
spec:
containers:
- args:
- --port=7472
- --config=config
image: harbor.wego.red/library/metallb/controller:v0.9.3 修改
imagePullPolicy: Always
name: controller
ports:
- containerPort: 7472
name: monitoring
resources:
limits:
cpu: 100m
memory: 100Mi
securityContext:
allowPrivilegeEscalation: false
capabilities:
drop:
- all
readOnlyRootFilesystem: true
nodeSelector:
beta.kubernetes.io/os: linux
securityContext:
runAsNonRoot: true
runAsUser: 65534
serviceAccountName: controller
terminationGracePeriodSeconds: 0
在master01应用资源清单文件
[root@master01 ~]# kubectl apply -f http://nginx.wego.red/service/metallb/metallb.yaml
创建secret 在master01节点执行如下命令 # On first install only # kubectl create secret generic -n metallb-system memberlist --from-literal=secretkey="$(openssl rand -base64 128)"
创建metallb配置文件
查看内容
[root@nginx metallb]# cat metallb-conf.yaml
apiVersion: v1
kind: ConfigMap
metadata:
namespace: metallb-system
name: config
data:
config: |
address-pools:
- name: default
protocol: layer2
addresses:
- 192.168.122.90-192.168.122.100
192.168.122.90-192.168.122.100是集群节点服务器IP同一段。
在master01节点应用资源清单文件
[root@master01 ~]# kubectl apply -f http://nginx.wego.red/service/metallb/metallb-conf.yaml
4.3.3.2.4发布Service类型为LoadBalancer的Deployment控制器类型应用
创建Deployment控制器类型应用nginx-metallb及service，service类型为LoadBalancer
[root@master01 ~]# vim 02_nginx-metabllb.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-metallb
spec:
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx-metallb1
image: harbor.wego.red/library/nginx:1.9.0
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx-metallb
spec:
ports:
- port: 8090
protocol: TCP
targetPort: 80
selector:
app: nginx
type: LoadBalancer
[root@master01 ~]# kubectl apply -f http://nginx.wego.red/service/metallb/nginx.yaml
4.3.3.2.2 验证
[root@master01 ~]# kubectl get ns NAME STATUS AGE default Active 16d kube-node-lease Active 16d kube-public Active 16d kube-system Active 16d kubernetes-dashboard Active 13d metallb-system Active 130m test1 Active 12d [root@master01 ~]# kubectl get pods -n metallb-system NAME READY STATUS RESTARTS AGE controller-64f8f944d-qdf8m 1/1 Running 0 110m speaker-cwzq7 1/1 Running 0 110m speaker-qk5fb 1/1 Running 0 110m speaker-wsllb 1/1 Running 0 110m speaker-x4bwt 1/1 Running 0 110m [root@master01 ~]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 16d nginx-metallb LoadBalancer 10.105.239.69 192.168.122.90 8090:31372/TCP 106m [root@master01 ~]# ping 192.168.122.90 PING 192.168.122.90 (192.168.122.90) 56(84) bytes of data. From 192.168.122.23: icmp_seq=2 Redirect Host(New nexthop: 192.168.122.90) From 192.168.122.23: icmp_seq=3 Redirect Host(New nexthop: 192.168.122.90)
4.3.3.2.3 访问
[root@master01 ~]# curl http://192.168.122.90:8090
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
body {
width: 35em;
margin: 0 auto;
font-family: Tahoma, Verdana, Arial, sans-serif;
}
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>
<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>
<p><em>Thank you for using nginx.</em></p>
</body>
</html>
如果在IPVS模式下使用kube-proxy，从Kubernetes v1.14.2开始，必须启用ARP模式。 可以通过在当前集群中编辑kube-proxy配置来实现： # kubectl edit configmap -n kube-system kube-proxy 并设置： apiVersion: kubeproxy.config.k8s.io/v1alpha1 kind: KubeProxyConfiguration mode: "ipvs" ipvs: strictARP: true
4.3.4 ExternalName
4.3.4.1 ExternalName作用
-
把集群外部的服务引入到集群内部中来，实现了集群内部pod和集群外部的服务进行通信
-
ExternalName 类型的服务适用于外部服务使用域名的方式，缺点是不能指定端口
-
还有一点要注意: 集群内的Pod会继承Node上的DNS解析规则。所以只要Node可以访问的服务，Pod中也可以访问到, 这就实现了集群内服务访问集群外服务
4.3.4.2 创建ExternalName Service
-
编写YAML文件
[root@master01 ~]# vim externalname.yaml apiVersion: v1 kind: Service metadata: name: my-service #对应的服务是my-service namespace: default spec: type: ExternalName externalName: www.baidu.com #对应的外部域名为www.baidu.com
-
应用YAML文件
[root@master01 ~]# kubectl apply -f externalname.yaml service/my-service configured
-
查看my-service的dns解析
[root@master01 ~]# kubectl get svc -n kube-system NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 18d [root@master01 ~]# dig -t A my-service.default.svc.cluster.local. @10.96.0.10 ; <<>> DiG 9.9.4-RedHat-9.9.4-72.el7 <<>> -t A my-service.default.svc.cluster.local. @10.96.0.10 ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43624 ;; flags: qr aa rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; WARNING: recursion requested but not available ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;my-service.default.svc.cluster.local. IN A ;; ANSWER SECTION: my-service.default.svc.cluster.local. 30 IN CNAME www.baidu.com. 注意这里 ;; Query time: 2001 msec ;; SERVER: 10.2.0.10#53(10.2.0.10) ;; WHEN: Mon Aug 05 21:23:38 CST 2019 ;; MSG SIZE rcvd: 133 从上面看到把外部域名做了一个别名过来
[root@master01 ~]# kubectl run busyboxapp --image=harbor.wego.red/library/busybox:1.28.4 -it If you don't see a command prompt, try pressing enter. / # nslookup my-service.default.svc.cluster.local. Server: 10.96.0.10 Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local Name: my-service.default.svc.cluster.local. Address 1: 2409:8c00:6c21:104f:0:ff:b03f:3ae Address 2: 2409:8c00:6c21:104c:0:ff:b02c:156c / # nslookup www.baidu.com Server: 10.96.0.10 Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local Name: www.baidu.com Address 1: 2409:8c00:6c21:104f:0:ff:b03f:3ae Address 2: 2409:8c00:6c21:104c:0:ff:b02c:156c
4.4 sessionAffinity
会话粘贴
设置sessionAffinity为Clientip (类似nginx的ip_hash算法,lvs的sh算法)
[root@nginx ~]# cat 02_create_deployment_app_nginx_with_service.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-server1
spec:
replicas: 2
selector:
matchLabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: c1
image: harbor.wego.red/library/nginx:1.9.0
imagePullPolicy: IfNotPresent
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx-svc
spec:
type: ClusterIP
ports:
- protocol: TCP
port: 80
targetPort: 80
selector:
app: nginx
[root@master01 ~]# kubectl apply -f http://nginx.wego.red/service/clusterip/02_create_deployment_app_nginx_with_service.yaml deployment.apps/nginx-server1 created service/nginx-svc created
[root@master01 ~]# kubectl get pods NAME READY STATUS RESTARTS AGE nginx-server1-58845f75f4-9zlnw 1/1 Running 0 2m11s nginx-server1-58845f75f4-ffqdt 1/1 Running 0 2m11s [root@master01 ~]# kubectl exec -it nginx-server1-58845f75f4-9zlnw bash kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl kubectl exec [POD] -- [COMMAND] instead. root@nginx-server1-58845f75f4-9zlnw:/# echo web1 > /usr/share/nginx/html/index.html root@nginx-server1-58845f75f4-9zlnw:/# exit exit [root@master01 ~]# kubectl exec -it nginx-server1-58845f75f4-ffqdt bash kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl kubectl exec [POD] -- [COMMAND] instead. root@nginx-server1-58845f75f4-ffqdt:/# echo web2 > /usr/share/nginx/html/index.html root@nginx-server1-58845f75f4-ffqdt:/# exit exit
[root@master01 ~]# kubectl get svc NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 16d nginx-svc ClusterIP 10.100.53.31 <none> 80/TCP 3m53s [root@master01 ~]# curl http://10.100.53.31 web1 [root@master01 ~]# curl http://10.100.53.31 web2 或 [root@master01 ~]# while true;do curl 10.100.53.31;sleep 1; done
[root@master01 ~]# kubectl patch svc nginx-svc -p '{"spec":{"sessionAffinity":"ClientIP"}}'
service/nginx-svc patched
[root@master01 ~]# curl 10.100.53.31
web1
多次访问,会话粘贴
设置回sessionAffinity为None
[root@master01 ~]# kubectl patch svc nginx-svc -p '{"spec":{"sessionAffinity":"None"}}'
service/my-service patched
测试 [root@master01 ~]# curl 10.100.53.31 web1 多次访问,回到负载均衡 或 [root@master01 ~]# while true;do curl 10.100.53.31;sleep 1; done web1 多次访问,会话粘贴
4.5 修改为ipvs调度方式
从kubernetes1.8版本开始，新增了kube-proxy对ipvs的支持，在kubernetes1.11版本中被纳入了GA.
4.5.1 修改为IPVS调度方式前升级内核
现使用Centos7u6发布版本，默认内核版本为3.10.0，使用kubernetes为1.18.0时，可升级内核版本至4.18.0或5.6.0版本。
在所有节点中安装,需要重启操作系统更换内核。以下升级方法供参考。
[root@localhost ~]# yum -y install perl [root@localhost ~]# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org [root@localhost ~]# yum -y install https://www.elrepo.org/elrepo-release-7.0-4.el7.elrepo.noarch.rpm [root@localhost ~]# yum --enablerepo="elrepo-kernel" -y install kernel-ml.x86_64 此处升级为5.0以上版本。 [root@localhost ~]# grub2-set-default 0 [root@localhost ~]# grub2-mkconfig -o /boot/grub2/grub.cfg [root@localhost ~]# reboot
4.5.2 修改kube-proxy的配置文件
[root@master01 ~]# kubectl edit configmap kube-proxy -n kube-system
26 iptables:
27 masqueradeAll: false
28 masqueradeBit: 14
29 minSyncPeriod: 0s
30 syncPeriod: 30s
31 ipvs:
32 excludeCIDRs: null
33 minSyncPeriod: 0s
34 scheduler: "" # 可以在这里修改ipvs的算法,默认为rr轮循算法
35 strictARP: false
36 syncPeriod: 30s
37 kind: KubeProxyConfiguration
38 metricsBindAddress: 127.0.0.1:10249
39 mode: "ipvs" # 默认""号里为空,加上ipvs
4.5.3 查看kube-system的namespace中kube-proxy有关的pod
[root@master01 ~]# kubectl get pods -n kube-system |grep kube-proxy kube-proxy-69mv6 1/1 Running 6 2d18h kube-proxy-jpc6c 1/1 Running 4 4d16h kube-proxy-kq65l 1/1 Running 4 4d16h kube-proxy-lmphf 1/1 Running 5 4d16h
4.5.4 验证kube-proxy-xxx的pod中的信息
[root@master01 ~]# kubectl logs kube-proxy-jpc6c -n kube-system W0517 00:55:10.914754 1 server_others.go:559] Unknown proxy mode "", assuming iptables proxy I0517 00:55:10.923228 1 node.go:136] Successfully retrieved node IP: 192.168.122.32 I0517 00:55:10.923264 1 server_others.go:186] Using iptables Proxier. I0517 00:55:10.923567 1 server.go:583] Version: v1.18.2 I0517 00:55:10.923965 1 conntrack.go:100] Set sysctl 'net/netfilter/nf_conntrack_max' to 131072 I0517 00:55:10.924001 1 conntrack.go:52] Setting nf_conntrack_max to 131072 I0517 00:55:10.924258 1 conntrack.go:83] Setting conntrack hashsize to 32768 I0517 00:55:10.927041 1 conntrack.go:100] Set sysctl 'net/netfilter/nf_conntrack_tcp_timeout_established' to 86400 I0517 00:55:10.927086 1 conntrack.go:100] Set sysctl 'net/netfilter/nf_conntrack_tcp_timeout_close_wait' to 3600 I0517 00:55:10.927540 1 config.go:315] Starting service config controller I0517 00:55:10.927556 1 shared_informer.go:223] Waiting for caches to sync for service config I0517 00:55:10.927576 1 config.go:133] Starting endpoints config controller I0517 00:55:10.927594 1 shared_informer.go:223] Waiting for caches to sync for endpoints config I0517 00:55:11.027749 1 shared_informer.go:230] Caches are synced for service config I0517 00:55:11.027858 1 shared_informer.go:230] Caches are synced for endpoints config
4.5.5 重新启动kube-proxy
删除kube-proxy-xxx的所有pod，让它重新拉取新的kube-proxy-xxx的pod
[root@master01 ~]# kubectl delete pod kube-proxy-69mv6 -n kube-system pod "kube-proxy-69mv6" deleted [root@master01 ~]# kubectl delete pod kube-proxy-jpc6c -n kube-system pod "kube-proxy-jpc6c" deleted [root@master01 ~]# kubectl delete pod kube-proxy-kq65l -n kube-system pod "kube-proxy-kq65l" deleted [root@master01 ~]# kubectl delete pod kube-proxy-lmphf -n kube-system pod "kube-proxy-lmphf" deleted
[root@master01 ~]# kubectl get pods -n kube-system |grep kube-proxy kube-proxy-2mk2b 1/1 Running 0 2m23s kube-proxy-5bj87 1/1 Running 0 30s kube-proxy-7qq9l 1/1 Running 0 52s kube-proxy-tjtqf 1/1 Running 0 80s
随意查看其中1个或3个kube-proxy-xxx的pod,验证是否为IPVS方式了 [root@master1 ~]# kubectl logs kube-proxy-tjtqf -n kube-system I0517 02:32:26.557696 1 node.go:136] Successfully retrieved node IP: 192.168.122.32 I0517 02:32:26.557745 1 server_others.go:259] Using ipvs Proxier. W0517 02:32:26.557912 1 proxier.go:429] IPVS scheduler not specified, use rr by default I0517 02:32:26.560008 1 server.go:583] Version: v1.18.2 I0517 02:32:26.560428 1 conntrack.go:52] Setting nf_conntrack_max to 131072 I0517 02:32:26.561094 1 config.go:315] Starting service config controller I0517 02:32:26.562251 1 shared_informer.go:223] Waiting for caches to sync for service config I0517 02:32:26.561579 1 config.go:133] Starting endpoints config controller I0517 02:32:26.562271 1 shared_informer.go:223] Waiting for caches to sync for endpoints config I0517 02:32:26.662541 1 shared_informer.go:230] Caches are synced for service config I0517 02:32:26.662566 1 shared_informer.go:230] Caches are synced for endpoints config
五、学习总结
六、课程预约
深入学习kubernetes，可以预约《kubernetes集群从入门到企业应用实战》相关课程。
文章来源:https://blog.csdn.net/qq_57747969/article/details/135137606
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本文来自互联网用户投稿，该文观点仅代表作者本人，不代表本站立场。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。 如若内容造成侵权/违法违规/事实不符，请联系我的编程经验分享网邮箱：chenni525@qq.com进行投诉反馈，一经查实，立即删除！
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