Kubernetes系列之Kubernetes使用ingress-nginx作为反向代理

#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

```

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 "<election-id>-<ingress-class>"

# Here: "<ingress-controller-leader>-<nginx>"

# 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-nginx

```

5、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 <none> <none>

nginx-ingress-controller-b44c4d4d7-zfj5n 1/1 Running 0 63s 172.16.17.193 huoban-k8s-master02 <none> <none>

[root@HUOBAN-K8S-MASTER01 mq1]# curl 172.16.17.192

<html>

<head><title>404 Not Found</title></head>

<body>

<center><h1>404 Not Found</h1></center>

<hr><center>openresty/1.15.8.1</center>

</body>

</html>

[root@HUOBAN-K8S-MASTER01 mq1]# curl 172.16.17.193

<html>

<head><title>404 Not Found</title></head>

<body>

<center><h1>404 Not Found</h1></center>

<hr><center>openresty/1.15.8.1</center>

</body>

</html>

# 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 <none> 80/TCP,443/TCP 112s app.kubernetes.io/name=ingress-nginx,app.kubernetes.io/part-of=ingress-nginx

# curl

<html>

<head><title>404 Not Found</title></head>

<body>

<center><h1>404 Not Found</h1></center>

<hr><center>openresty/1.15.8.1</center>

</body>

</html>

```

7、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:

- port: 80

selector:

app: app-nginx

tier: production

---

apiVersion: autoscaling/v1

kind: HorizontalPodAutoscaler

metadata:

name: app-nginx

spec:

maxReplicas: 3

minReplicas: 1

scaleTargetRef:

apiVersion: extensions/v1beta1

kind: Deployment

name: app-nginx

targetCPUUtilizationPercentage: 80

---

apiVersion: apps/v1

kind: Deployment

metadata:

name: app-nginx

labels:

app: app-nginx

spec:

replicas: 1

selector:

matchLabels:

app: app-nginx

tier: production

template:

metadata:

labels:

app: app-nginx

tier: production

spec:

containers:

- name: app-nginx

image: harbor.huoban.com/open/huoban-nginx:v1.1

imagePullPolicy: IfNotPresent

resources:

requests:

memory: "50Mi"

cpu: "25m"

ports:

- containerPort: 80

name: nginx

volumeMounts:

- name: html

mountPath: /usr/share/nginx/html

- name: conf

mountPath: /etc/nginx/conf.d

volumes:

- name: html

nfs:

path: /open/web/app

server: 192.168.101.11

- name: conf

nfs:

path: /open/conf/app/nginx

server: 192.168.101.11

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:

-

secretName: bjwf-ingress-secret

rules:

- host:

http:

paths:

- path: /

backend:

serviceName: app-nginx

servicePort: 80

```

8、访问服务（这块就不截图了。已经能正常跳转至443）