service
- 一、简介
- 二、开启kube-proxy的ipvs模式:
- 三、创建service:(NodePort方式)
- 四、指定一个 LoadBalancer 类型的 Service
- 五、service允许为其分配一个公有IP
- 六、k8s网络通信，配置flannel
一、简介
- Service 是由 kube-proxy 组件,加上 iptables 来共同实现的.
• kube-proxy 通过 iptables 处理 Service 的过程,需要在宿主机上设置相当多的
iptables 规则,如果宿主机有大量的Pod,不断刷新iptables规则,会消耗大量的
CPU资源。
• IPVS模式的service,可以使K8s集群支持更多量级的Pod。
二、开启kube-proxy的ipvs模式:
[root@server4 pod]# kubectl -n kube-system get pod |grep proxy
[root@server4 pod]# kubectl -n kube-system get pod -o wide |grep proxy
[root@server4 pod]# kubectl -n kube-system get cm
[root@server4 pod]# kubectl -n kube-system get cm kube-proxy
[root@server4 pod]# kubectl edit cm kube-proxy -n kube-system
configmap/kube-proxy edited
[root@server4 pod]# kubectl get pod -n kube-system |grep kube-proxy | awk '{system("kubectl delete pod "$1" -n kube-system")}'
pod "kube-proxy-cmq2v" deleted
pod "kube-proxy-hqzkh" deleted
pod "kube-proxy-mjzh2" deleted
[root@server4 pod]# ip addr
三、创建service:(NodePort方式)
[root@server4 pod]# vim svc.yaml #创建service:(NodePort方式)
[root@server4 pod]# kubectl edit svc mysvc
service/mysvc edited
[root@server4 pod]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
demo ClusterIP 10.97.29.222 <none> 80/TCP 23h
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 2d23h
mysvc NodePort 10.100.22.177 <none> 80:31525/TCP 4m18s
[root@server4 pod]# netstat -antlp | grep 31525
[root@server4 pod]# kubectl run demo --image=busyboxplus -it
If you don't see a command prompt, try pressing enter.
/ # nslookup nginx-svc
Server: 10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
[root@server4 pod]# dig -t A nginx-svc.default.svc.cluster.local. @10.96.0.10
四、指定一个 LoadBalancer 类型的 Service
1.下载镜像
[root@foundation15 ~]# lftp 172.25.254.250
lftp 172.25.254.250:~> cd pub/docs/k8s/
cd ok, cwd=/pub/docs/k8s
lftp 172.25.254.250:/pub/docs/k8s> get metallb.yaml
8447 bytes transferred
lftp 172.25.254.250:/pub/docs/k8s> get metallb-v0.10.2.tar
90602496 bytes transferred
lftp 172.25.254.250:/pub/docs/k8s> exit
[root@foundation15 ~]# ls
3.0.115 manifests rht-ks-post.log
compose metallb-v0.10.2.tar rht-ks-pre.log
daemon.json metallb.yaml root@172.25.15.1
get-docker.sh Pictures root@172.25.15.4
k8s-1.21.3.tar 'rhel6 lanmp.pdf' zabbix.api
kube-flannel.yml rhel-server-7.6-x86_64-dvd.iso
[root@foundation15 ~]# scp metallb-v0.10.2.tar metallb.yaml 172.25.15.4:
root@172.25.15.4's password:
metallb-v0.10.2.tar 100% 86MB 106.3MB/s 00:00
metallb.yaml 100% 8447 374.5KB/s 00:00
[root@foundation15 ~]#
2.上传镜像
[root@server4 ~]# ls
kube-flannel.yml metallb-v0.10.2.tar metallb.yaml pod
[root@server4 ~]# docker load -i metallb-v0.10.2.tar
b2d5eeeaba3a: Loading layer 5.88MB/5.88MB
a273cec6d851: Loading layer 40.54MB/40.54MB
Loaded image: reg.westos.org/metallb/controller:v0.10.2
b763436ff23f: Loading layer 44.15MB/44.15MB
Loaded image: reg.westos.org/metallb/speaker:v0.10.2
[root@server4 ~]# docker push reg.westos.org/metallb/speaker:v0.10.2
The push refers to repository [reg.westos.org/metallb/speaker]
b763436ff23f: Pushed
b2d5eeeaba3a: Pushed
v0.10.2: digest: sha256:b5e9cb99c22f8379238784b611bc3ddde18120f9a4b7481ea888ed9c72854222 size: 952
[root@server4 ~]# docker push reg.westos.org/metallb/controller:v0.10.2
The push refers to repository [reg.westos.org/metallb/controller]
a273cec6d851: Pushed
b2d5eeeaba3a: Mounted from metallb/speaker
v0.10.2: digest: sha256:1ed3d2bf860220557b0d862d0f4fc07ae84b33def79595489041186906e58e3d size: 952
[root@server4 ~]#
3.实现负载均衡
在service提交后,Kubernetes就会调用 CloudProvider 在公有云上为你创建一个负载均衡服务,并且把被代理的 Pod 的 IP地址配置给负载均衡服
务做后端。
[root@server4 metallb]# ls
configmap.yaml lb-svc.yaml metallb.yaml
[root@server4 metallb]# kubectl apply -f lb-svc.yaml
service/lb-svc unchanged
[root@server4 metallb]# kubectl apply -f configmap.yaml
configmap/config unchanged
[root@server4 metallb]# kubectl apply -f metallb.yaml
[root@server4 metallb]# kubectl apply -f lb-svc.yaml
service/lb-svc unchanged
[root@server4 metallb]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
demo ClusterIP 10.97.29.222 <none> 80/TCP 24h
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d
lb-svc LoadBalancer 10.103.125.6 172.25.15.10 80:32421/TCP 5m20s
[root@server4 metallb]#
[root@foundation15 ~]# curl 172.25.15.10
Hello MyApp | Version: v1 | <a href="hostname.html">Pod Name</a>
[root@foundation15 ~]# curl 172.25.15.10/hostname.html
replicaset-example-j4lt7
[root@foundation15 ~]# curl 172.25.15.10/hostname.html
replicaset-example-9hbdm
五、service允许为其分配一个公有IP
[root@server4 metallb]# ls
configmap.yaml lb-svc.yaml metallb.yaml
[root@server4 metallb]# vim ext-ip.yaml
[root@server4 metallb]# cat ext-ip.yaml
apiVersion: v1
kind: Service
metadata:
name: ex-service
spec:
selector:
app: myapp
ports:
- name: http
protocol: TCP
port: 80
targetPort: 80
externalIPs:
- 172.25.15.100
[root@server4 metallb]# kubectl apply -f ext-ip.yaml
service/ex-service created
[root@server4 metallb]# kubectl get svc
- 一种全局的、为了代理不同后端 Service 而设置的负载均衡服务,就是 Kubernetes 里的Ingress 服务。
- • Ingress由两部分组成:Ingress controller和Ingress服务。
- • Ingress Controller 会根据你定义的 Ingress 对象,提供对应的代理能力。业界常用的各种反向代理项目,比如 Nginx、HAProxy、Envoy、Traefik 等,都已经为Kubernetes专门维护了对应的 Ingress Controller。
[root@server4 metallb]# vim ex-svc.yaml
apiVersion: v1
kind: Service
metadata:
name: my-service
spec:
type: ExternalName
externalName: www.westos.org
[root@server4 metallb]# kubectl apply -f ex-svc.yaml
service/my-service created
[root@server4 metallb]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
demo ClusterIP 10.97.29.222 <none> 80/TCP 26h
ex-service ClusterIP 10.110.22.46 172.25.15.100 80/TCP 93m
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d2h
lb-svc LoadBalancer 10.103.125.6 172.25.15.10 80:32421/TCP 129m
my-service ExternalName <none> www.westos.org <none> 4s
[root@server4 metallb]# kubectl edit svc my-service
service/my-service edited
[root@server4 metallb]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
demo ClusterIP 10.97.29.222 <none> 80/TCP 27h
ex-service ClusterIP 10.110.22.46 172.25.15.100 80/TCP 94m
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3d2h
lb-svc LoadBalancer 10.103.125.6 172.25.15.10 80:32421/TCP 129m
my-service ExternalName <none> www.baidu.com <none> 39s
[root@server4 metallb]# dig -t A my-service.default.svc.cluster.local. @10.96.0.10
六、k8s网络通信，配置flannel
flannel支持多种后端：
Vxlan
vxlan //报文封装，默认
Directrouting //直接路由，跨网段使用vxlan，同网段使用host-gw模式。
host-gw： //主机网关，性能好，但只能在二层网络中，不支持跨网络， 如果有成千上万的Pod，容易产生广播风暴，不推荐
UDP： //性能差，不推荐
[root@server4 ~]# cd pod
[root@server4 pod]# ls
cronjob.yaml headless.yaml job.yaml pod.yaml svc.yaml
deployment.yaml init.yaml perl.tar rs.yaml
[root@server4 pod]# kubectl apply -f deployment.yaml
deployment.apps/nginx-deployment created
模式修改为host-gw
[root@server4 ~]# kubectl -n kube-system get pod
[root@server4 ~]# kubectl -n kube-system edit cm kube-flannel-cfg
net-conf.json: |
{
"Network": "10.244.0.0/16",
"Backend": {
"Type": "host-gw" #模式修改
}
}
[root@server4 ~]# kubectl -n kube-system get pod
[root@server4 ~]# kubectl get pod -n kube-system |grep kube-flannel | awk '{system("kubectl delete pod "$1" -n kube-system")}'
[root@server4 ~]# kubectl get pod -o wide
[root@server4 ~]# route -n
[root@server2 ~]# route -n
[root@server3 ~]# route -n