Nginx-ingress 架构和原理
迅速回顾一下 Nginx-ingress 的架构和实现原理：
Nginx-ingress 通过前置的 Loadbalancer 类型的 Service 接收集群流量，将流量转发至 Nginx-ingress Pod 内并对配置的策略进行检查，再转发至目标 Service，最终将流量转发至业务容器。
传统的 Nginx 需要我们配置 conf 文件策略。但 Nginx-ingress 通过实现 Nginx-ingress-Controller 将原生 conf 配置文件和 yaml 配置文件进行了转化，当我们配置 yaml 文件的策略后，Nginx-ingress-Controller 将对其进行转化，并且动态更新策略，动态 Reload Nginx Pod，实现自动管理。
那么 Nginx-ingress-Controller 如何能够动态感知集群的策略变化呢？方法有很多种，可以通过 webhook admission 拦截器，也可以通过 ServiceAccount 与 Kubernetes Api 进行交互，动态获取。Nginx-ingress-Controller 使用后者来实现。所以在部署 Nginx-ingress 我们会发现 Deployment 内指定了 Pod 的 ServiceAccount，以及实现了 RoleBinding ，最终达到 Pod 与 Kubernetes Api 交互的目标。
dev
apiVersion: v1
kind: Namespace
metadata:
name: dev
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
namespace: dev
spec:
selector:
matchLabels:
app: nginx
replicas: 1
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: wangweicoding-docker.pkg.coding.net/nginx-ingress-gray/docker/nginx
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx
namespace: dev
spec:
ports:
- name: tcp-80-80
port: 80
protocol: TCP
targetPort: 80
selector:
app: nginx
sessionAffinity: None
type: NodePort
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: nginx # nginx=nginx-ingress| qcloud=CLB ingress
## kubernetes.io/ingress.subnetId: subnet-xxxxxxxx # if qcloud, should give subnet
name: my-ingress
namespace: dev
spec:
rules:
- host: nginx-ingress.coding.dev
http:
paths:
- backend:
serviceName: nginx
servicePort: 80
path: /
Prd
apiVersion: v1
kind: Namespace
metadata:
name: pro
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx
namespace: pro
spec:
selector:
matchLabels:
app: nginx
replicas: 1
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: wangweicoding-docker.pkg.coding.net/nginx-ingress-gray/docker/nginx
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx
namespace: pro
spec:
ports:
- name: tcp-80-80
port: 80
protocol: TCP
targetPort: 80
selector:
app: nginx
sessionAffinity: None
type: NodePort
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: nginx # nginx=nginx-ingress| qcloud=CLB ingress
## kubernetes.io/ingress.subnetId: subnet-xxxxxxxx # if qcloud, should give subnet
name: my-ingress
namespace: pro
spec:
rules:
- host: nginx-ingress.coding.pro
http:
paths:
- backend:
serviceName: nginx
servicePort: 80
path: /
Canary
apiVersion: v1
kind: Namespace
metadata:
name: pro
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: nginx-canary
namespace: pro
spec:
selector:
matchLabels:
app: nginx-canary
replicas: 1
template:
metadata:
labels:
app: nginx-canary
spec:
containers:
- name: nginx
image: wangweicoding-docker.pkg.coding.net/nginx-ingress-gray/docker/nginx
ports:
- containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
name: nginx-canary
namespace: pro
spec:
ports:
- name: tcp-80-80
port: 80
protocol: TCP
targetPort: 80
selector:
app: nginx-canary
sessionAffinity: None
type: NodePort
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
kubernetes.io/ingress.class: nginx # nginx=nginx-ingress| qcloud=CLB ingress
## kubernetes.io/ingress.subnetId: subnet-xxxxxxxx # if qcloud, should give subnet
nginx.ingress.kubernetes.io/canary: "true"
nginx.ingress.kubernetes.io/canary-by-header: "location"
nginx.ingress.kubernetes.io/canary-by-header-value: "shenzhen"
#nginx.ingress.kubernetes.io/canary-weight: 100
name: my-ingress
namespace: pro
spec:
rules:
- host: nginx-ingress.coding.pro
http:
paths:
- backend:
serviceName: nginx-canary
servicePort: 80
path: /
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