我要评论ingress 理论
ingress 简介
在kubernetes中，pod的ip地址和service的clusterip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，
kubernetes目前提供了以下几种方案：
1、nodeport：
2、loadbalancer：.
3、externalips：
4、ingress：
ingress 组成
1、ingress： nginx配置文件
ingress是一个api对象，通过yaml文件来配置，ingress对象的作用是定义请求如何转发到service的规则，可以理解为配置模板。
ingress通过http或https暴露集群内部service，给service提供外部url、负载均衡、ssl/tls以及基于域名的反向代理。ingress要依靠 ingress-controller 来具体实现以上功能。
2、ingress-controller： 当做反向代理或者说是转发器
ingress-controller是具体实现反向代理及负载均衡的程序，对ingress定义的规则进行解析，根据配置的规则来实现请求转发。
ingress-controller并不是k8s自带的组件，实际上ingress-controller只是一个统称，用户可以选择不同的ingress-controller实现，目前，由k8s维护的ingress-controller只有google云的gce与ingress-nginx两个，其他还有很多第三方维护的ingress-controller，具体可以参考官方文档。但是不管哪一种ingress-controller，实现的机制都大同小异，只是在具体配置上有差异。
一般来说，ingress-controller的形式都是一个pod，里面跑着daemon程序和反向代理程序。daemon负责不断监控集群的变化，根据 ingress对象生成配置并应用新配置到反向代理，比如ingress-nginx就是动态生成nginx配置，动态更新upstream，并在需要的时候reload程序应用新配置。为了方便，后面的例子都以k8s官方维护的ingress-nginx为例。
总结：ingress-controller才是负责具体转发的组件，通过各种方式将它暴露在集群入口，外部对集群的请求流量会先到 ingress-controller， 而ingress对象是用来告诉ingress-controller该如何转发请求，比如哪些域名、哪些url要转发到哪些service等等。
ingress 工作原理
- ingress-controller通过和 kubernetes apiserver 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。以此达到域名区分配置和动态更新的作用。
实例部署
/部署 nginx-ingress-controller
1、部署ingress-controller pod及相关资源
mkdir /opt/ingress
cd /opt/ingress
#mandatory.yaml文件中包含了很多资源的创建，包括namespace、configmap、role，serviceaccount等等所有部署ingress-controller需要的资源。
2、修改 clusterrole 资源配置
vim mandatory.yaml
......
apiversion: rbac.authorization.k8s.io/v1beta1
#rbac相关资源从1.17版本开始改用rbac.authorization.k8s.io/v1，rbac.authorization.k8s.io/v1beta1在1.22版本即将弃用
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" # （0.25版本）增加 networking.k8s.io ingress 资源的 api
resources:
- ingresses
verbs:
- get
- list
- watch
- apigroups:
- ""
resources:
- events
verbs:
- create
- patch
- apigroups:
- "extensions"
- "networking.k8s.io" # （0.25版本）增加 networking.k8s.io/v1 ingress 资源的 api
resources:
- ingresses/status
verbs:
- update
ingress 暴露服务的方式
1、方式一：deployment+loadbalancer 模式的 service
2、方式二：daemonset+hostnetwork+nodeselector
3、方式三：deployment+nodeport模式的service
采用方式二：daemonset+hostnetwork+nodeselector
3、指定 nginx-ingress-controller 运行在 node02 节点
kubectl label node node02 ingress=true
kubectl get nodes --show-labels
4、修改 deployment 为 daemonset ，指定节点运行，并开启 hostnetwork 网络
vim mandatory.yaml
...
apiversion: apps/v1
# 修改 kind
# kind: deployment
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:
# 删除replicas
# 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:
# 使用主机网络
hostnetwork: true
# 选择节点运行
nodeselector:
ingress: "true"
serviceaccountname: nginx-ingress-serviceaccount
......
5、在所有 node 节点上传 nginx-ingress-controller 镜像压缩包 ingree.contro.tar.gz 到 /opt/ingress 目录，并解压和加载镜像
cd /opt/ingress
tar zxvf ingree.contro.tar.gz
docker load -i ingree.contro.tar
6、启动 nginx-ingress-controller
//nginx-ingress-controller 已经运行 node02 节点
kubectl get pod -n ingress-nginx -o wide
name ready status restarts age ip node nominated node readiness gates
nginx-ingress-controller-99h72 1/1 running 0 93s 192.168.10.21 node02 <none> <none>
kubectl get cm,daemonset -n ingress-nginx -o wide
name data age
configmap/ingress-controller-leader-nginx 0 100s
configmap/nginx-configuration 0 102s
configmap/tcp-services 0 102s
configmap/udp-services 0 102s
name desired current ready up-to-date available node selector age
nginx-ingress-controller 1 1 1 1 1 ingress=true 16m
//到 node02 节点查看
netstat -lntp | grep nginx
7、创建 ingress 规则
.
//创建一个 deploy 和 svc
vim service-nginx.yaml
apiversion: apps/v1
kind: deployment
metadata:
name: nginx-app
spec:
replicas: 2
selector:
matchlabels:
app: nginx
template:
metadata:
labels:
app: nginx
spec:
containers:
- name: nginx
image: nginx
imagepullpolicy: ifnotpresent
ports:
- containerport: 80
---
apiversion: v1
kind: service
metadata:
name: nginx-app-svc
spec:
type: clusterip
ports:
- protocol: tcp
port: 80
targetport: 80
selector:
app: nginx
创建 ingress
方法一：（extensions/v1beta1 ingress 在1.22版本即将弃用）
vim ingress-app.yaml
apiversion: extensions/v1beta1
kind: ingress
metadata:
name: nginx-app-ingress
spec:
rules:
- host: www.kgc.com
http:
paths:
- path: /
backend:
servicename: nginx-app-svc
serviceport: 80
方法二：
vim ingress-app.yaml
apiversion: networking.k8s.io/v1
kind: ingress
metadata:
name: nginx-app-ingress
spec:
rules:
- host: www.kgc.com
http:
paths:
- path: /
pathtype: prefix
backend:
service:
name: nginx-app-svc
port:
number: 80
kubectl apply -f service-nginx.yaml
kubectl apply -f ingress-app.yaml
kubectl get pods
kubectl get ingress8、测试访问
本地 host 添加域名解析
vim /etc/hosts9、查看 nginx-ingress-controller
kubectl get pod -n ingress-nginx -o wide
kubectl exec -it nginx-ingress-controller-99h72 -n ingress-nginx /bin/bash
# more /etc/nginx/nginx.conf
//可以看到从 start server www.kgc.com 到 end server www.kgc.com 之间包含了此域名用于反向代理的配置
采用方式三：deployment+nodeport模式的service
1、下载 nginx-ingress-controller 和 ingress-nginx 暴露端口配置文件
mkdir /opt/ingress-nodeport
cd /opt/ingress-nodeport
2、在所有 node 节点上传镜像包 ingress-controller-0.30.0.tar 到 /opt/ingress-nodeport 目录，并加载镜像
docker load -i ingress-controller-0.30.0.tar
3、启动 nginx-ingress-controller
kubectl apply -f mandatory.yaml
kubectl apply -f service-nodeport.yaml
-------------------------------------------------------------------------------------------
//如果k8s pod 调度失败，在 kubectl describe pod资源时显示：
warning failedscheduling 18s (x2 over 18s) default-scheduler 0/2 nodes are available: 2 node(s) didn't match node selector
解决方案：
1. 给需要调度的node加上对应标签
# 相对上面这个yaml文件的例子
kubectl label nodes node_name kubernetes.io/os=linux
2. 删除yaml文件中的nodeselector，如果对节点没有要求的话，直接删除节点选择器即可
kubectl get pod,svc -n ingress-nginx
ingress http 代理访问
cd /opt/ingress-nodeport
创建 deployment、service、ingress yaml 资源
vim ingress-nginx.yaml
apiversion: apps/v1
kind: deployment
metadata:
name: nginx-app
spec:
replicas: 2
selector:
matchlabels:
name: nginx
template:
metadata:
labels:
name: nginx
spec:
containers:
- name: nginx
image: nginx
imagepullpolicy: ifnotpresent
ports:
- containerport: 80
---
apiversion: v1
kind: service
metadata:
name: nginx-svc
spec:
ports:
- port: 80
targetport: 80
protocol: tcp
selector:
name: nginx
---
apiversion: networking.k8s.io/v1
kind: ingress
metadata:
name: nginx-test
spec:
rules:
- host: www.benet.com
http:
paths:
- path: /
pathtype: prefix
backend:
service:
name: nginx-svc
port:
number: 80
kubectl apply -f ingress-nginx.yaml
kubectl get svc,pods -o wide
kubectl exec -it pod/nginx-app-65d7b99f6b-l4g65 bash
kubectl exec -it pod/nginx-app-65d7b99f6b-zcqgp bash
测试访问
curl 10.96.212.214
kubectl get svc -n ingress-nginx
本地 host 添加域名解析
vim /etc/hosts
ingress http 代理访问虚拟主机
mkdir /opt/ingress-nodeport/vhost
cd /opt/ingress-nodeport/vhost
创建虚拟主机1资源
vim deployment1.yaml
apiversion: apps/v1
kind: deployment
metadata:
name: deployment1
spec:
replicas: 2
selector:
matchlabels:
name: nginx1
template:
metadata:
labels:
name: nginx1
spec:
containers:
- name: nginx1
image: soscscs/myapp:v1
imagepullpolicy: ifnotpresent
ports:
- containerport: 80
---
apiversion: v1
kind: service
metadata:
name: svc-1
spec:
ports:
- port: 80
targetport: 80
protocol: tcp
selector:
name: nginx1
kubectl apply -f deployment1.yaml
创建虚拟主机2资源
vim deployment2.yaml
apiversion: apps/v1
kind: deployment
metadata:
name: deployment2
spec:
replicas: 2
selector:
matchlabels:
name: nginx2
template:
metadata:
labels:
name: nginx2
spec:
containers:
- name: nginx2
image: soscscs/myapp:v2
imagepullpolicy: ifnotpresent
ports:
- containerport: 80
---
apiversion: v1
kind: service
metadata:
name: svc-2
spec:
ports:
- port: 80
targetport: 80
protocol: tcp
selector:
name: nginx2
kubectl apply -f deployment2.yaml
创建ingress资源
vim ingress-nginx.yaml
apiversion: networking.k8s.io/v1
kind: ingress
metadata:
name: ingress1
spec:
rules:
- host: www1.kgc.com
http:
paths:
- path: /
pathtype: prefix
backend:
service:
name: svc-1
port:
number: 80
---
apiversion: networking.k8s.io/v1
kind: ingress
metadata:
name: ingress2
spec:
rules:
- host: www2.kgc.com
http:
paths:
- path: /
pathtype: prefix
backend:
service:
name: svc-2
port:
number: 80
kubectl apply -f ingress-nginx.yaml
测试访问
kubectl get svc -n ingress-nginx
ingress https 代理访问
mkdir /opt/ingress-nodeport/https
cd /opt/ingress-nodeport/https
创建ssl证书
openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout tls.key -out tls.crt -subj "/cn=nginxsvc/o=nginxsvc"
创建 secret 资源进行存储
kubectl create secret tls tls-secret --key tls.key --cert tls.crt
kubectl get secret
kubectl describe secret tls-secret
创建 deployment、service、ingress yaml 资源
vim ingress-https.yaml
apiversion: apps/v1
kind: deployment
metadata:
name: nginx-app
spec:
replicas: 2
selector:
matchlabels:
name: nginx
template:
metadata:
labels:
name: nginx
spec:
containers:
- name: nginx
image: nginx
imagepullpolicy: ifnotpresent
ports:
- containerport: 80
---
apiversion: v1
kind: service
metadata:
name: nginx-svc
spec:
ports:
- port: 80
targetport: 80
protocol: tcp
selector:
name: nginx
---
apiversion: networking.k8s.io/v1
kind: ingress
metadata:
name: nginx-https
spec:
tls:
- hosts:
- www3.kgc.com
secretname: tls-secret
rules:
- host: www3.kgc.com
http:
paths:
- path: /
pathtype: prefix
backend:
service:
name: nginx-svc
port:
number: 80
kubectl apply -f ingress-https.yaml
kubectl get svc -n ingress-nginx
访问测试
nginx 进行 basicauth
mkdir /opt/ingress-nodeport/basic-auth
cd /opt/ingress-nodeport/basic-auth
生成用户密码认证文件，创建 secret 资源进行存储
yum -y install httpd
htpasswd -c auth zhangsan #认证文件名必须为 auth
kubectl create secret generic basic-auth --from-file=auth
创建 ingress 资源
vim ingress-auth.yaml
apiversion: networking.k8s.io/v1
kind: ingress
metadata:
name: ingress-auth
annotations:
#设置认证类型basic
nginx.ingress.kubernetes.io/auth-type: basic
#设置secret资源名称basic-auth
nginx.ingress.kubernetes.io/auth-secret: basic-auth
#设置认证窗口提示信息
nginx.ingress.kubernetes.io/auth-realm: 'authentication required - zhangsan'
spec:
rules:
- host: auth.kgc.com
http:
paths:
- path: /
pathtype: prefix
backend:
service:
name: nginx-svc
port:
number: 80
//具体详细设置方法可参考官网https://kubernetes.github.io/ingress-nginx/examples/auth/basic/
kubectl apply -f ingress-auth.yaml
访问测试
kubectl get svc -n ingress-nginx
echo '192.168.10.19 auth.kgc.com' >> /etc/hosts
浏览器访问：http://auth.kgc.com:32383
nginx 进行重写
metadata.annotations 配置说明- nginx.ingress.kubernetes.io/rewrite-target: <字符串> #必须重定向流量的目标uri
- nginx.ingress.kubernetes.io/ssl-redirect: <布尔值> #指示位置部分是否仅可访问ssl(当ingress包含证书时，默认为true)
- nginx.ingress.kubernetes.io/force-ssl-redirect: <布尔值> #即使ingress未启用tls，也强制重定向到https
- nginx.ingress.kubernetes.io/app-root: <字符串> #定义controller必须重定向的应用程序根，如果它在'/'上下文中
- nginx.ingress.kubernetes.io/use-regex: <布尔值> #指示ingress上定义的路径是否使用正则表达式
vim ingress-rewrite.yaml
apiversion: networking.k8s.io/v1
kind: ingress
metadata:
name: nginx-rewrite
annotations:
nginx.ingress.kubernetes.io/rewrite-target: http://www1.kgc.com:32383
spec:
rules:
- host: re.kgc.com
http:
paths:
- path: /
pathtype: prefix
backend:
#由于re.kgc.com只是用于跳转不需要真实站点存在，因此svc资源名称可随意定义
service:
name: nginx-svc
port:
number: 80
kubectl apply -f ingress-rewrite.yaml
echo '192.168.10.21 re.kgc.com' >> /etc/hosts
浏览器访问：http://re.kgc.com:32383
总结
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