k8s中负载均衡器【ingress-nginx】部署
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
本节主要就ingress和ingress控制器ingress-nginx-controller的部署作简单介绍和记录。
以下系统组件版本：
云服务器：centos版本7.6.1810、k8s版本1.15.0、docker版本18.06.1-ce、ingress-nginx-controller版本0.25.0
Ingress
[*] Ingress 组成？
[*] 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
[*] 将新加入的Ingress转化成Nginx的配置文件并使之生效
[*] ingress controller
[*] ingress服务
[*] Ingress 工作原理?
[*] ingress controller通过和kubernetes api交互，动态的去感知集群中ingress规则变化，
[*] 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，
[*] 再写到nginx-ingress-controller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，
[*] 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。
[*] Ingress 可以解决什么问题？
[*] 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.
[*] 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
[*] Ingress当前的实现方式？
ingress-nginx-controller
目前最新版本的ingress-nginx-controller，用lua实现了当upstream变化时不用reload，大大减少了生产环境中由于服务的重启、升级引起的IP变化导致的nginx reload。
以下就ingress-nginx-controller的部署做简单记录：
yaml如下：
[*]
kubectl apply -f {如下文件}
[*]
apiVersion: v1kind: Namespacemetadata:name: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx---kind: ConfigMapapiVersion: v1metadata:name: nginx-configurationnamespace: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx---kind: ConfigMapapiVersion: v1metadata:name: tcp-servicesnamespace: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx---kind: ConfigMapapiVersion: v1metadata:name: udp-servicesnamespace: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx---apiVersion: v1kind: ServiceAccountmetadata:name: nginx-ingress-serviceaccountnamespace: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginx---apiVersion: rbac.authorization.k8s.io/v1beta1kind: ClusterRolemetadata:name: nginx-ingress-clusterrolelabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxrules:- 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/v1beta1kind: Rolemetadata:name: nginx-ingress-rolenamespace: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxrules:- 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/v1beta1kind: RoleBindingmetadata:name: nginx-ingress-role-nisa-bindingnamespace: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxroleRef:apiGroup: rbac.authorization.k8s.iokind: Rolename: nginx-ingress-rolesubjects:- kind: ServiceAccount name: nginx-ingress-serviceaccount namespace: ingress-nginx---apiVersion: rbac.authorization.k8s.io/v1beta1kind: ClusterRoleBindingmetadata:name: nginx-ingress-clusterrole-nisa-bindinglabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxroleRef:apiGroup: rbac.authorization.k8s.iokind: ClusterRolename: nginx-ingress-clusterrolesubjects:- kind: ServiceAccount name: nginx-ingress-serviceaccount namespace: ingress-nginx---apiVersion: apps/v1kind: Deploymentmetadata:name: nginx-ingress-controllernamespace: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxspec:replicas: 1selector: matchLabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxtemplate: 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: serviceAccountName: nginx-ingress-serviceaccount containers: - name: nginx-ingress-controller image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.25.0 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 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--- 在墙内会拉取不到以下镜像：
[*]
quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.25.0 可以使用国内阿里云镜像：
[*]
docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/nginx-ingress-controller:0.25.0 安装后，在ingress-nginx命名空间下可以看到pod一直pending，describe pod报如下警告：
查看master节点默认加了污点，一般不允许pod调度到master节点：
如果k8s集群只有一个节点，可以在pod的spec下设置容忍该污点：
即：
[*]
spec: tolerations: - effect: NoSchedule key: node-role.kubernetes.io/master 可以看到ingress-nginx pod被调度到master节点，且变为Running
看日志报以下警告：
[*]
W0714 13:31:04.883127 6 queue.go:130] requeuing &ObjectMeta{Name:sync status,GenerateName:,Namespace:,SelfLink:,UID:,ResourceVersion:,Generation:0,CreationTimestamp:0001-01-01 00:00:00 +0000 UTC,DeletionTimestamp:<nil>,DeletionGracePeriodSeconds:nil,Labels:mapstring{},Annotations:mapstring{},OwnerReferences:[],Finalizers:[],ClusterName:,Initializers:nil,ManagedFields:[],}, err services "ingress-nginx" not found 需要创一个名为ingress-nginx的service：
[*]
kubectl apply -f {如下文件}
[*]
kind: ServiceapiVersion: v1metadata:name: ingress-nginxnamespace: ingress-nginxlabels: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxspec:externalTrafficPolicy: Localtype: LoadBalancerselector: app.kubernetes.io/name: ingress-nginx app.kubernetes.io/part-of: ingress-nginxports: - name: http port: 80 targetPort: http - name: https port: 443 targetPort: https 参考：
ingress deploy
https://github.com/kubernetes/ingress-nginx/blob/master/docs/deploy/index.md
Taint和Toleration（污点和容忍）
https://jimmysong.io/kubernetes-handbook/concepts/taint-and-toleration.html
k8s 1.12部署ingress-nginx
https://www.jianshu.com/p/e30b06906b77
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文档来源：51CTO技术博客https://blog.51cto.com/coderaction/2995474
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