kubernetes學習筆記之七： Ingress-nginx 部署使用

一、Ingress 簡介

在Kubernetes中，服務和Pod的IP地址僅可以在集群網絡內部使用，對於集群外的應用是不可見的。為了使外部的應用能夠訪問集群內的服務，在Kubernetes 目前 提供了以下幾種方案：
NodePort LoadBalancer Ingress

Ingress 組成

ingress controller
　　將新加入的Ingress轉化成Nginx的配置文件並使之生效
ingress服務
　　將Nginx的配置抽象成一個Ingress對象，每添加一個新的服務只需寫一個新的Ingress的yaml文件即可

Ingress 工作原理

1.ingress controller通過和kubernetes api交互，動態的去感知集群中ingress規則變化， 2.然后讀取它，按照自定義的規則，規則就是寫明了哪個域名對應哪個service，生成一段nginx配置， 3.再寫到nginx-ingress-control的pod里，這個Ingress controller的pod里運行着一個Nginx服務，控制器會把生成的nginx配置寫入/etc/nginx.conf文件中， 4.然后reload一下使配置生效。以此達到域名分配置和動態更新的問題。

Ingress 可以解決什么問題

1.動態配置服務
　　如果按照傳統方式, 當新增加一個服務時, 我們可能需要在流量入口加一個反向代理指向我們新的k8s服務. 而如果用了Ingress, 只需要配置好這個服務, 當服務啟動時, 會自動注冊到Ingress的中, 不需要而外的操作.
2.減少不必要的端口暴露
　　配置過k8s的都清楚, 第一步是要關閉防火牆的, 主要原因是k8s的很多服務會以NodePort方式映射出去, 這樣就相當於給宿主機打了很多孔, 既不安全也不優雅. 而Ingress可以避免這個問題, 除了Ingress自身服務可能需要映射出去, 其他服務都不要用NodePort方式

二、部署配置Ingress

1 .部署文件介紹、准備

獲取配置文件位置: https://github.com/kubernetes/ingress-nginx/tree/nginx-0.20.0/deploy

下載部署文件

提供了兩種方式 ： 　　默認下載最新的yaml： 　　　　wget https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/mandatory.yaml
　　指定版本號下載對應的yaml 　　　　

 部署文件介紹

1.namespace.yaml  創建一個獨立的命名空間 ingress-nginx
 2.configmap.yaml  ConfigMap是存儲通用的配置變量的，類似於配置文件，使用戶可以將分布式系統中用於不同模塊的環境變量統一到一個對象中管理；而它與配置文件的區別在於它是存在集群的“環境”中的，並且支持K8S集群中所有通用的操作調用方式。 從數據角度來看，ConfigMap的類型只是鍵值組，用於存儲被Pod或者其他資源對象（如RC）訪問的信息。這與secret的設計理念有異曲同工之妙，主要區別在於ConfigMap通常不用於存儲敏感信息，而只存儲簡單的文本信息。 ConfigMap可以保存環境變量的屬性，也可以保存配置文件。 創建pod時，對configmap進行綁定，pod內的應用可以直接引用ConfigMap的配置。相當於configmap為應用/運行環境封裝配置。 pod使用ConfigMap，通常用於：設置環境變量的值、設置命令行參數、創建配置文件。 3.default-backend.yaml 如果外界訪問的域名不存在的話，則默認轉發到default-http-backend這個Service，其會直接返回404： 4.rbac.yaml  負責Ingress的RBAC授權的控制，其創建了Ingress用到的ServiceAccount、ClusterRole、Role、RoleBinding、ClusterRoleBinding 5.with-rbac.yaml 是Ingress的核心，用於創建ingress-controller。前面提到過，ingress-controller的作用是將新加入的Ingress進行轉化為Nginx的配置

2.部署ingress

准備鏡像，從這里mandatory.yaml查看需要哪些鏡像

鏡像名稱	版本	下載地址
k8s.gcr.io/defaultbackend-amd64	1.5	registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64
quay.io/kubernetes-ingress-controller/nginx-ingress-controller	0.20.0	registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/nginx-ingress-controller

在每一個節點(Node)上下載鏡像:

[root@k8s-node1 ~]# docker pull registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5 #注意版本號 Trying to pull repository registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64 ... 1.5: Pulling from registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64 26de8f6c1f4b: Pull complete Digest: sha256:2cdff48ab9b20ca5f9b0ee48bf3c139c51d6fb1a15245966583bc371c121c238 Status: Downloaded newer image for registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5 [root@k8s-node1 ~]#  docker pull registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/nginx-ingress-controller:0.20.0 #注意版本號 Trying to pull repository registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/nginx-ingress-controller ... 0.20.0: Pulling from registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/nginx-ingress-controller 8e41b996a802: Pull complete f8e7d603ef88: Pull complete 610da4f3123f: Pull complete 62702a85e6c9: Pull complete 7cedf5b2083f: Pull complete 755f7fa719b6: Pull complete 6adbdd0c8aaf: Pull complete 2389d8b0d2a2: Pull complete 1ea794448393: Pull complete bb0c388ee432: Pull complete 9626641c5a97: Pull complete bd0bebb5ba38: Pull complete Digest: sha256:3f06079f7727b2fb7ad5c97d8152eb622ae504674395dfa71fda7ce315aaaf30 Status: Downloaded newer image for registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/nginx-ingress-controller:0.20.0 [root@k8s-node1 ~]# docker images #檢查鏡像是否下載成功 REPOSITORY TAG IMAGE ID CREATED SIZE registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64       1.5                 d8f37b8cdaf4        2 weeks ago         5.13 MB registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/nginx-ingress-controller   0.20.0              3cc332ecde4f        3 weeks ago         513 MB k8s.gcr.io/kube-proxy-amd64                                                   v1.10.0             bfc21aadc7d3        7 months ago        97 MB k8s.gcr.io/kube-controller-manager-amd64                                      v1.10.0             ad86dbed1555        7 months ago        148 MB k8s.gcr.io/kube-scheduler-amd64                                               v1.10.0             704ba848e69a        7 months ago        50.4 MB k8s.gcr.io/kube-apiserver-amd64                                               v1.10.0             af20925d51a3        7 months ago        225 MB k8s.gcr.io/etcd-amd64                                                         3.1.12              52920ad46f5b        8 months ago        193 MB k8s.gcr.io/kubernetes-dashboard-amd64                                         v1.8.3              0c60bcf89900        8 months ago        102 MB quay.io/coreos/flannel                                                        v0.10.0-amd64       f0fad859c909        9 months ago        44.6 MB k8s.gcr.io/k8s-dns-dnsmasq-nanny-amd64                                        1.14.8              c2ce1ffb51ed        10 months ago       41 MB k8s.gcr.io/k8s-dns-sidecar-amd64                                              1.14.8              6f7f2dc7fab5        10 months ago       42.2 MB k8s.gcr.io/k8s-dns-kube-dns-amd64                                             1.14.8              80cc5ea4b547        10 months ago       50.5 MB k8s.gcr.io/pause-amd64                                                        3.1                 da86e6ba6ca1        10 months ago       742 kB docker.io/kubeguide/tomcat-app                                                v1                  a29e200a18e9        2 years ago         358 MB

下載yaml文件並更新mandatory.yaml中的鏡像地址（master上）

[root@k8s-master ~]# mkdir ingress-nginx [root@k8s-master ingress-nginx]# wget  https://raw.githubusercontent.com/kubernetes/ingress-nginx/nginx-0.20.0/deploy/mandatory.yaml
[root@k8s-master ingress-nginx]# wget  https://raw.githubusercontent.com/kubernetes/ingress-nginx/master/deploy/provider/baremetal/service-nodeport.yaml #對外提供服務，如果不需要可以不下載
[root@k8s-master ingress-nginx]# sed -i 's#k8s.gcr.io/defaultbackend-amd64#registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64#g' mandatory.yaml  #替換defaultbackend-amd64鏡像地址 sed -i 's#quay.io/kubernetes-ingress-controller/nginx-ingress-controller#registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/nginx-ingress-controller#g' mandatory.yaml  #替換nginx-ingress-controller鏡像地址 [root@k8s-master ingress-nginx]# grep image mandatory.yaml #檢查替換結果 # Any image is permissible as long as: image: registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5 image: registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/nginx-ingress-controller:0.20.0

修改service-nodeport.yaml文件，添加NodePort端口，默認為隨機端口

[root@k8s-master ingress-nginx]# cat service-nodeport.yaml 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: type: NodePort ports: - name: http port: 80 targetPort: 80 protocol: TCP nodePort: 32080 #http
    - name: https port: 443 targetPort: 443 protocol: TCP nodePort: 32443 #https selector: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx

部署nginx-ingress-controller

[root@k8s-master ingress-nginx]# kubectl apply -f mandatory.yaml namespace "ingress-nginx" created deployment.extensions "default-http-backend" created service "default-http-backend" 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.extensions "nginx-ingress-controller" created [root@k8s-master ingress-nginx]# kubectl apply -f service-nodeport.yaml service "ingress-nginx" created

3.查看ingress-nginx組件狀態

[root@k8s-master ingress-nginx]#  kubectl get pods -n ingress-nginx #pod狀態 NAME READY STATUS RESTARTS AGE default-http-backend-66c4fbf5b4-x2n8w       1/1       Running   0 58s nginx-ingress-controller-64bcff8657-5gdrd   1/1       Running   0 58s [root@k8s-master ingress-nginx]#  kubectl get svc -n ingress-nginx #service狀態及暴露端口 NAME TYPE CLUSTER-IP      EXTERNAL-IP PORT(S) AGE default-http-backend   ClusterIP   10.96.87.65     <none>        80/TCP 1m ingress-nginx          NodePort    10.100.48.237   <none>        80:32080/TCP,443:32443/TCP   1m

4.訪問ingress-nginx服務，查看是否配置成功

可以看到，提示404，這個因為當前ingress-nginx服務現在還沒有后端服務，這是正常的

三、創建ingress-nginx后端服務

1.創建一個Service及后端Deployment(以nginx為例)

[root@k8s-master01 ingress]# cat deploy-demon.yaml apiVersion: v1 kind: Service metadata: name: myapp namespace: default spec: selector: app: myapp release: canary ports: - name: http port: 80 targetPort: 80
--- apiVersion: apps/v1 kind: Deployment metadata: name: myapp-deploy spec: replicas: 5 selector: matchLabels: app: myapp release: canary template: metadata: labels: app: myapp release: canary spec: containers: - name: myapp image: ikubernetes/myapp:v2 ports: - name: httpd containerPort: 80

創建相關服務及檢查狀態是否就緒

[root@k8s-master ingress-nginx]# kubectl apply -f deploy-demon.yaml service "myapp" created deployment.apps "myapp-deploy" created [root@k8s-master ingress-nginx]# kubectl get pods NAME READY STATUS RESTARTS AGE myapp-deploy-5cfd895984-ffzm5   1/1       Running   0 1m myapp-deploy-5cfd895984-ftg9t   1/1       Running   0 1m myapp-deploy-5cfd895984-jg887   1/1       Running   0 1m myapp-deploy-5cfd895984-mk4jq   1/1       Running   0 1m myapp-deploy-5cfd895984-nqz6s   1/1       Running   0 1m myweb-hrfqm                     1/1       Running   0 8d myweb-pb5tb                     1/1       Running   0 8d myweb-xrk22                     1/1       Running   0 8d [root@k8s-master ingress-nginx]# kubectl get svc NAME TYPE CLUSTER-IP       EXTERNAL-IP PORT(S) AGE kubernetes ClusterIP 10.96.0.1        <none>        443/TCP 9d myapp ClusterIP 10.102.30.215    <none>        80/TCP 1m myweb NodePort 10.106.138.244   <none>        8080:31888/TCP   8d

將myapp添加至ingress-nginx中

[root@k8s-master ingress-nginx]# cat ingress-myapp.yaml apiVersion: extensions/v1beta1 kind: Ingress metadata: name: ingress-myapp namespace: default annotations: kubernetes.io/ingress.class: "nginx" spec: rules: - host: myapp.magedu.com #生產中該域名應當可以被公網解析 http: paths: - path: backend: serviceName: myapp servicePort: 80

[root@k8s-master ingress-nginx]# kubectl apply -f ingress-myapp.yaml  
ingress.extensions "ingress-myapp" created

配置域名解析，當前測試環境我們使用hosts文件進行解析

172.33.16.241  myapp.magedu.com  

使用域名進行訪問

2.再創建一個Service及后端Deployment(以tomcat為例)

[root@k8s-master ingress-nginx]# cat tomcat-deploy.yaml apiVersion: v1 kind: Service metadata: name: tomcat namespace: default spec: selector: app: tomcat release: canary ports: - name: http port: 8080 targetPort: 8080
  - name: ajp port: 8009 targetPort: 8009

--- apiVersion: apps/v1 kind: Deployment metadata: name: tomcat-deploy spec: replicas: 3 selector: matchLabels: app: tomcat release: canary template: metadata: labels: app: tomcat release: canary spec: containers: - name: tomcat image: tomcat:7-alpine ports: - name: httpd containerPort: 8080
        - name: ajp containerPort: 8009 [root@k8s-master ingress-nginx]# kubectl apply -f tomcat-deploy.yaml service "tomcat" created deployment.apps "tomcat-deploy" created [root@k8s-master ingress-nginx]# kubectl get pod #等待pod狀態就緒

將tomcat添加至ingress-nginx中

[root@k8s-master ingress-nginx]# cat ingress-tomcat.yaml apiVersion: extensions/v1beta1 kind: Ingress metadata: name: ingress-tomcat namespace: default annotations: kubernets.io/ingress.class: "nginx" spec: rules: - host: tomcat.magedu.com http: paths: - path: backend: serviceName: tomcat servicePort: 8080 [root@k8s-master ingress-nginx]# kubectl apply -f ingress-tomcat.yaml ingress.extensions "ingress-tomcat" created

添加域名解析及訪問服務

 

3.下面我們對tomcat服務添加httpds服務

創建私有證書及secret

[root@k8s-master ingress-nginx]# openssl genrsa -out tls.key 2048 Generating RSA private key, 2048 bit long modulus .......+++ ..............................+++ e is 65537 (0x10001) [root@k8s-master ingress-nginx]# openssl req -new -x509 -key tls.key -out tls.crt -subj /C=CN/ST=Beijing/L=Beijing/O=DevOps/CN=tomcat.magedu.com #注意域名要和服務的域名一致 [root@k8s-master ingress-nginx]# kubectl create secret tls tomcat-ingress-secret --cert=tls.crt --key=tls.key #創建secret secret "tomcat-ingress-secret" created [root@k8s-master ingress-nginx]# kubectl get secret NAME TYPE DATA AGE default-token-bf52l     kubernetes.io/service-account-token   3 9d tomcat-ingress-secret   kubernetes.io/tls                     2 7s [root@k8s-master ingress-nginx]# kubectl describe secret tomcat-ingress-secret Name: tomcat-ingress-secret Namespace: default Labels: <none> Annotations: <none> Type: kubernetes.io/tls Data ==== tls.crt: 1294 bytes #base64加密 tls.key: 1679 bytes

將證書應用至tomcat服務中

[root@k8s-master01 ingress]# cat ingress-tomcat-tls.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: ingress-tomcat-tls
  namespace: default
  annotations: 
    kubernets.io/ingress.class: "nginx"
spec:
  tls:
  - hosts:
    - tomcat.magedu.com        #與secret證書的域名需要保持一致
    secretName: tomcat-ingress-secret   #secret證書的名稱
  rules:
  - host: tomcat.magedu.com
    http:
      paths:
      - path: 
        backend:
          serviceName: tomcat
          servicePort: 8080

[root@k8s-master01 ingress]#  kubectl apply -f ingress-tomcat-tls.yaml

訪問服務

 

#參考文檔：

https://www.jianshu.com/p/e30b06906b77

https://kubernetes.io/docs/concepts/services-networking/ingress/

https://kubernetes.github.io/ingress-nginx/deploy/

https://github.com/kubernetes/ingress-nginx/blob/nginx-0.20.0/docs/deploy/index.md