什么是Ingress
Ingress对象，其实就是对反向代理的一种抽象，简单的说就是衣蛾全局的负载均衡器，可以通过访问URL定位到后端的Service
有了Ingress这个抽象，K8S就不需要关心Ingress的细节了，实际使用时，只需要选择一个具体的Ingress Controller部署就行了，业界常用的反向代理项目有：Nginx、HAProxy、Envoy、Traefik，都已经成为了K8S专门维护的Ingress Controller
一个Ingress对象的主要内容，就类似Nginx的配置文件描述，对应的转发规则就是ingressRule，
有了Ingress这个对象，用户就可以根据自己的需求选择Ingress Controller，例如，如果应用对代理服务的中断非常敏感，可以使用Treafik这样的Ingress Controller
Ingress工作在七层，Service工作在四层，当想要在Kubernetes里为应用进行TLS配置等HTTPS相关操作时，都必须通过Ingress来进行
LoadBalancer的Service也会在公有云创建负载均衡，但是是一个Servcie对应一个，太浪费了
以下以演示部署一个Nginx Ingress Controller，并代理一个我们自己创建的服务coffee
Nginx Ingress Controller 官网地址：https://kubernetes.github.io/ingress-nginx
依赖的其他github相关yaml文件：https://github.com/nginxinc/kubernetes-ingress/tree/master/examples/complete-example
pod与ingress的关系
•通过label-selector相关联
•通过Ingress Controller实现Pod的负载均衡
-支持TCP/UDP 4层和HTTP 7层
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
使用Ingress
步骤如下所示
- 部署ingress Controller【需要下载官方的】
- 创建ingress规则【对哪个Pod、名称空间配置规则】
创建Nginx Pod
创建一个nginx应用，然后对外暴露端口
# 创建pod kubectl create deployment web --image=nginx # 查看 kubectl get pods
对外暴露端口
kubectl expose deployment web --port=80 --target-port=80 --type=NodePort
部署 ingress controller
下面我们来通过yaml的方式，部署我们的ingress，配置文件如下所示
kubectl apply -f https://github.com/kubernetes/ingress-nginx/blob/nginx-0.20.0/deploy/mandatory.yaml内容如下
apiVersion: v1
kind: Namespace
metadata:
name: ingress-nginx
---
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
name: default-http-backend
labels:
app.kubernetes.io/name: default-http-backend
app.kubernetes.io/part-of: ingress-nginx
namespace: ingress-nginx
spec:
replicas: 1
selector:
matchLabels:
app.kubernetes.io/name: default-http-backend
app.kubernetes.io/part-of: ingress-nginx
template:
metadata:
labels:
app.kubernetes.io/name: default-http-backend
app.kubernetes.io/part-of: ingress-nginx
spec:
terminationGracePeriodSeconds: 60
containers:
- name: default-http-backend
# Any image is permissible as long as:
# 1. It serves a 404 page at /
# 2. It serves 200 on a /healthz endpoint
image: k8s.gcr.io/defaultbackend-amd64:1.5
livenessProbe:
httpGet:
path: /healthz
port: 8080
scheme: HTTP
initialDelaySeconds: 30
timeoutSeconds: 5
ports:
- containerPort: 8080
resources:
limits:
cpu: 10m
memory: 20Mi
requests:
cpu: 10m
memory: 20Mi
---
apiVersion: v1
kind: Service
metadata:
name: default-http-backend
namespace: ingress-nginx
labels:
app.kubernetes.io/name: default-http-backend
app.kubernetes.io/part-of: ingress-nginx
spec:
ports:
- port: 80
targetPort: 8080
selector:
app.kubernetes.io/name: default-http-backend
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-nginx
---
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:
- "extensions"
resources:
- ingresses
verbs:
- get
- list
- watch
- apiGroups:
- ""
resources:
- events
verbs:
- create
- patch
- apiGroups:
- "extensions"
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: extensions/v1beta1
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: 1
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:
serviceAccountName: nginx-ingress-serviceaccount
containers:
- name: nginx-ingress-controller
image: quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.20.0
args:
- /nginx-ingress-controller
- --default-backend-service=$(POD_NAMESPACE)/default-http-backend
- --configmap=$(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:
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: 1
readinessProbe:
failureThreshold: 3
httpGet:
path: /healthz
port: 10254
scheme: HTTP
periodSeconds: 10
successThreshold: 1
timeoutSeconds: 1
---
通过这种方式，其实我们在外面就能访问，这里还需要在外面添加一层
kubectl apply -f ingress-con.yaml
最后通过下面命令，查看是否成功部署 ingress
kubectl get pods -n ingress-nginx
创建ingress规则文件
创建ingress规则文件，ingress-h.yaml
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: ingress-test
spec:
rules:
- host: ingress.test.com
http:
paths:
- path: /
backend:
serviceName: my-dep
servicePort: 80
添加域名访问规则
在windows 的 hosts文件，添加域名访问规则【因为我们没有域名解析，所以只能这样做】
最后通过域名就能访问