nginx ingress按照http header进行路由
1 概述：
1.1 环境
版本信息如下：
a、操作系统：centos 7.6
b、kubernetes版本：v1.15.0
c、ingress nginx版本：0.47.0
1.2 nginx按照http header转发流量
nginx的配置文件nginx.confg中，可使用if语句块来转发流量，表达式包含http header的判断，执行语句是proxy_pass指令，格式类似：
if ($http_region = "sz") {
proxy_pass http://echo-sz.default:80;
break;
}
在kubernetes ingress背景下，nginx controller包含了nginx和一个控制器，用户只需要把以上配置块写入ingress的注解区域即可使得nginx根据http header转发数据的效果，因为控制器会将ingress中的数据进行转化再写入到nginx配置文件中。
1.3 部署环境
1.3.1 部署ingress nginx controller
将以下文件进行kubectl apply：
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-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
data:
resolv.conf: |
nameserver 10.96.0.10
search default.svc.cluster.local svc.cluster.local cluster.local lj.io
options ndots:5
kind: ConfigMap
metadata:
name: resolver
namespace: 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"
- "networking.k8s.io"
resources:
- ingresses
verbs:
- get
- list
- watch
- update
- 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 "-"
# Here: "-"
# 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: v1
kind: Service
metadata:
name: ingress-nginx
namespace: ingress-nginx
spec:
ports:
- port: 80
protocol: TCP
targetPort: 80
selector:
app.kubernetes.io/name: ingress-nginx
sessionAffinity: None
type: ClusterIP
---
apiVersion: apps/v1
kind: DaemonSet
metadata:
name: nginx-ingress-controller
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
spec:
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
hostNetwork: true
dnsPolicy: ClusterFirstWithHostNet
containers:
- name: nginx-ingress-controller
image: bitnami/nginx-ingress-controller:0.47.0
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
部署效果如下，本案例中是以daemonset形式部署nginx controller，使用host网络，并且dnsPolicy为ClusterFirstWithHostNet，如此一来在nginx容器中可使用kubernetes内部域名来访问后端服务。
1.3.2 部署三个测试服务echo-server
部署echo-gz，等价于位于gz机房。
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: echo-gz
name: echo-gz
namespace: default
spec:
replicas: 1
selector:
matchLabels:
app: echo-gz
template:
metadata:
labels:
app: echo-gz
spec:
containers:
- env:
- name: NODE_NAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: spec.nodeName
- name: POD_NAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.namespace
- name: POD_IP
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: status.podIP
image: registry.aliyuncs.com/google_containers/echoserver:1.10
imagePullPolicy: IfNotPresent
name: echo
ports:
- containerPort: 8080
protocol: TCP
resources:
limits:
cpu: "2"
memory: 100Mi
requests:
cpu: 100m
memory: 100Mi
---
apiVersion: v1
kind: Service
metadata:
labels:
app: echo-gz
name: echo-gz
namespace: default
spec:
ports:
- name: http
port: 80
protocol: TCP
targetPort: 8080
selector:
app: echo-gz
type: NodePort
部署echo-sz，等价于位于sz机房。
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: echo-sz
name: echo-sz
namespace: default
spec:
replicas: 1
selector:
matchLabels:
app: echo-sz
template:
metadata:
labels:
app: echo-sz
spec:
containers:
- env:
- name: NODE_NAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: spec.nodeName
- name: POD_NAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.namespace
- name: POD_IP
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: status.podIP
image: registry.aliyuncs.com/google_containers/echoserver:1.10
imagePullPolicy: IfNotPresent
name: echo
ports:
- containerPort: 8080
protocol: TCP
resources:
limits:
cpu: "2"
memory: 100Mi
requests:
cpu: 100m
memory: 100Mi
---
apiVersion: v1
kind: Service
metadata:
labels:
app: echo-sz
name: echo-sz
namespace: default
spec:
ports:
- name: http
port: 80
protocol: TCP
targetPort: 8080
selector:
app: echo-sz
type: NodePort
部署echo-bj，等价于位于bj机房。
apiVersion: apps/v1
kind: Deployment
metadata:
labels:
app: echo-bj
name: echo-bj
namespace: default
spec:
replicas: 1
selector:
matchLabels:
app: echo-bj
template:
metadata:
labels:
app: echo-bj
spec:
containers:
- env:
- name: NODE_NAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: spec.nodeName
- name: POD_NAME
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.name
- name: POD_NAMESPACE
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: metadata.namespace
- name: POD_IP
valueFrom:
fieldRef:
apiVersion: v1
fieldPath: status.podIP
image: registry.aliyuncs.com/google_containers/echoserver:1.10
imagePullPolicy: IfNotPresent
name: echo
ports:
- containerPort: 8080
protocol: TCP
resources:
limits:
cpu: "2"
memory: 100Mi
requests:
cpu: 100m
memory: 100Mi
---
apiVersion: v1
kind: Service
metadata:
labels:
app: echo-bj
name: echo-bj
namespace: default
spec:
ports:
- name: http
port: 80
protocol: TCP
targetPort: 8080
selector:
app: echo-bj
type: NodePort
部署后的效果如图所示：
访问service的80端口，即可访问对应的后端服务。
2 创建kubernetes ingress对象
执行kubectl apply命令创建ingress对象。
流量转发效果是：
a、默认访问echo-gz服务；
b、如果请求带region=bj，则访问echo-bj服务；
c、如果请求带region=sz，则访问echo-sz服务。
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/configuration-snippet: |
if ($http_region = "bj") {
proxy_pass http://echo-bj.default:80;
break;
}
if ($http_region = "sz") {
proxy_pass http://echo-sz.default:80;
break;
}
name: echo
namespace: default
spec:
rules:
- host: www.example.com
http:
paths:
- backend:
serviceName: echo-gz
servicePort: 80
path: /apis/echo
3 测试nginx的转发效果
使用curl命令访问nginx，其中一个虚拟机节点的IP是192.168.0.70，域名是www.example.com。可见，满足上面讲的转发效果。
