Kubernetes系列之Kubernetes使用ingress-nginx作为反向代理
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#一、Ingress简介
在Kubernetes中，服务和Pod的IP地址仅可以在集群网络内部使用，对于集群外的应用是不可见的。为了使外部的应用能够访问集群内的服务，在Kubernetes 目前 提供了以下几种方案：
NodePort
LoadBalancer
Ingress
###1、Ingress组成
ingress controller
将新加入的Ingress转化成Nginx的配置文件并使之生效
ingress服务
将Nginx的配置抽象成一个Ingress对象，每添加一个新的服务只需写一个新的Ingress的yaml文件即可
###2、Ingress工作原理
1.ingress controller通过和kubernetes api交互，动态的去感知集群中ingress规则变化，
2.然后读取它，按照自定义的规则，规则就是写明了哪个域名对应哪个service，生成一段nginx配置，
3.再写到nginx-ingress-control的pod里，这个Ingress controller的pod里运行着一个Nginx服务，控制器会把生成的nginx配置写入/etc/nginx.conf文件中，
4.然后reload一下使配置生效。以此达到域名分配置和动态更新的问题。
###3、Ingress 可以解决什么问题
1.动态配置服务
如果按照传统方式, 当新增加一个服务时, 我们可能需要在流量入口加一个反向代理指向我们新的k8s服务. 而如果用了Ingress, 只需要配置好这个服务, 当服务启动时, 会自动注册到Ingress的中, 不需要而外的操作.
2.减少不必要的端口暴露
配置过k8s的都清楚, 第一步是要关闭防火墙的, 主要原因是k8s的很多服务会以NodePort方式映射出去, 这样就相当于给宿主机打了很多孔, 既不安全也不优雅. 而Ingress可以避免这个问题, 除了Ingress自身服务可能需要映射出去, 其他服务都不要用NodePort方式
#二、部署配置ingress-nginx
1、下载配置文件（下载的整合文件）
# cd /data/kubernetes/ingress-nginx
# wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/static/mandatory.yaml
2、文件说明
可以分成五个单独的文件
1.namespace.yaml
创建一个独立的命名空间 ingress-nginx
2.configmap.yaml
ConfigMap是存储通用的配置变量的，类似于配置文件，使用户可以将分布式系统中用于不同模块的环境变量统一到一个对象中管理；而它与配置文件的区别在于它是存在集群的“环境”中的，并且支持K8S集群中所有通用的操作调用方式。
从数据角度来看，ConfigMap的类型只是键值组，用于存储被Pod或者其他资源对象（如RC）访问的信息。这与secret的设计理念有异曲同工之妙，主要区别在于ConfigMap通常不用于存储敏感信息，而只存储简单的文本信息。
ConfigMap可以保存环境变量的属性，也可以保存配置文件。
创建pod时，对configmap进行绑定，pod内的应用可以直接引用ConfigMap的配置。相当于configmap为应用/运行环境封装配置。
pod使用ConfigMap，通常用于：设置环境变量的值、设置命令行参数、创建配置文件。
3.default-backend.yaml
如果外界访问的域名不存在的话，则默认转发到default-http-backend这个Service，其会直接返回404：
4.rbac.yaml
负责Ingress的RBAC授权的控制，其创建了Ingress用到的ServiceAccount、ClusterRole、Role、RoleBinding、ClusterRoleBinding
5.with-rbac.yaml
是Ingress的核心，用于创建ingress-controller。前面提到过，ingress-controller的作用是将新加入的Ingress进行转化为Nginx的配置
3、选择要部署的节点
#给master002和master003打上标签
kubectl label nodes huoban-k8s-master02 kubernetes.io=nginx-ingress
kubectl label nodes huoban-k8s-master03 kubernetes.io=nginx-ingress
4、修改配置文件
vim mandatory.yaml
apiVersion: v1
kind: Namespace
metadata:
name: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
kind: ConfigMap
apiVersion: v1
metadata:
name: nginx-configuration
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginxs
data:
proxy-body-size: "200m"
kind: ConfigMap
apiVersion: v1
metadata:
name: tcp-services
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
kind: ConfigMap
apiVersion: v1
metadata:
name: udp-services
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
apiVersion: v1
kind: ServiceAccount
metadata:
name: nginx-ingress-serviceaccount
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
name: nginx-ingress-clusterrole
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
rules:
- apiGroups:
- ""
resources: - configmaps
- endpoints
- nodes
- pods
- secrets
verbs: - list
- watch
- apiGroups:
- ""
resources: - nodes
verbs: - get
- apiGroups:
- ""
resources: - services
verbs: - get
- list
- watch
- apiGroups:
- ""
resources: - events
verbs: - create
- patch
- apiGroups:
- "extensions"
- "networking.k8s.io"
resources: - ingresses
verbs: - get
- list
- watch
- apiGroups:
- "extensions"
- "networking.k8s.io"
resources: - ingresses/status
verbs: - update
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: Role
metadata:
name: nginx-ingress-role
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
rules:
- apiGroups:
- ""
resources: - configmaps
- pods
- secrets
- namespaces
verbs: - get
- apiGroups:
- ""
resources: - configmaps
resourceNames:Defaults to "-"
Here: "-"
This has to be adapted if you change either parameter
when launching the nginx-ingress-controller.
- "ingress-controller-leader-nginx"
verbs: - get
- update
- apiGroups:
- ""
resources: - configmaps
verbs: - create
- apiGroups:
- ""
resources: - endpoints
verbs: - get
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
name: nginx-ingress-role-nisa-binding
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: nginx-ingress-role
subjects:
- kind: ServiceAccount
name: nginx-ingress-serviceaccount
namespace: ingress-nginx
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: nginx-ingress-clusterrole-nisa-binding
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: nginx-ingress-clusterrole
subjects:
- kind: ServiceAccount
name: nginx-ingress-serviceaccount
namespace: ingress-nginx
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-ingress-controller
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
spec:
replicas: 2
selector:
matchLabels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
template:
metadata:
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
annotations:
prometheus.io/port: "10254"
prometheus.io/scrape: "true"
spec:
nodeSelector:
kubernetes.io: nginx-ingress
tolerations:
- effect: NoSchedule
operator: Exists
hostNetwork: true
serviceAccountName: nginx-ingress-serviceaccount
containers:- name: nginx-ingress-controller
image: registry.cn-hangzhou.aliyuncs.com/google_containers/nginx-ingress-controller:0.25.1
imagePullPolicy: IfNotPresent
args:- /nginx-ingress-controller
- --configmap=$(POD_NAMESPACE)/nginx-configuration
- --tcp-services-configmap=$(POD_NAMESPACE)/tcp-services
- --udp-services-configmap=$(POD_NAMESPACE)/udp-services
- --publish-service=$(POD_NAMESPACE)/ingress-nginx
- --annotations-prefix=nginx.ingress.kubernetes.io
securityContext:
allowPrivilegeEscalation: true
capabilities:
drop:- ALL
add: - NET_BIND_SERVICE
www-data -> 33
runAsUser: 33
env:
- name: POD_NAME
valueFrom:
fieldRef:
fieldPath: metadata.name - name: POD_NAMESPACE
valueFrom:
fieldRef:
fieldPath: metadata.namespace
ports: - name: http
containerPort: 80 - name: https
containerPort: 443
volumeMounts:- name: ssl
mountPath: /etc/ingress-controller/ssl
livenessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
initialDelaySeconds: 10
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 10
readinessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 10
volumes:
name: ssl
nfs:
path: /conf/global_sign_ssl
server: 0a52248244-vcq8.cn-hangzhou.nas.aliyuncs.com
apiVersion: v1
kind: Service
metadata:
name: ingress-nginx
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
spec:
ports:
- name: http
port: 80
targetPort: 80
protocol: TCP - name: https
port: 443
targetPort: 443
protocol: TCP
selector:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx5、部署
kubectl apply -f mandatory.yaml
namespace/ingress-nginx created
configmap/nginx-configuration created
configmap/tcp-services created
configmap/udp-services created
serviceaccount/nginx-ingress-serviceaccount created
clusterrole.rbac.authorization.k8s.io/nginx-ingress-clusterrole created
role.rbac.authorization.k8s.io/nginx-ingress-role created
rolebinding.rbac.authorization.k8s.io/nginx-ingress-role-nisa-binding created
clusterrolebinding.rbac.authorization.k8s.io/nginx-ingress-clusterrole-nisa-binding created
deployment.apps/nginx-ingress-controller created
service/ingress-nginx created
6、访问测试
kubectl get pods -n ingress-nginx -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-ingress-controller-b44c4d4d7-9rprz 1/1 Running 0 63s 172.16.17.192 huoban-k8s-master03
nginx-ingress-controller-b44c4d4d7-zfj5n 1/1 Running 0 63s 172.16.17.193 huoban-k8s-master02
[root@HUOBAN-K8S-MASTER01 mq1]# curl 172.16.17.192
404 Not Found
404 Not Found
openresty/1.15.8.1
[root@HUOBAN-K8S-MASTER01 mq1]# curl 172.16.17.193
404 Not Found
404 Not Found
openresty/1.15.8.1
kubectl get svc -n ingress-nginx -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
ingress-nginx ClusterIP 10.100.243.171 80/TCP,443/TCP 112s app.kubernetes.io/name=ingress-nginx,app.kubernetes.io/part-of=ingress-nginx
curl http://10.100.243.171
404 Not Found404 Not Found
openresty/1.15.8.17、部署一个应用测试一下
1、创建一个nginx应用
vim app-nginx.yaml
apiVersion: v1
kind: Service
metadata:
name: app-nginx
labels:
app: app-nginx
spec:
ports:
2、创建TLS证书
kubectl create secret tls bjwf-ingress-secret --cert=server.crt --key=server.key --dry-run -o yaml > bjwf-ingress-secret.yaml
3、创建应用的ingress
vim app-nginx-ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: app-ingress
namespace: default
spec:
tls:
- hosts:
- www.bjwf125.com
secretName: bjwf-ingress-secret
rules: - host: www.bjwf125.com
http:
paths:
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