Kubernetes

ingress拓宽篇

1. 生成 CA 证书

在现在大部分场景下面我们都会使用 https 来访问我们的服务，这节课我们将使用一个自签名的证书，当然你有在一些正规机构购买的 CA 证书是最好的，这样任何人访问你的服务的时候都是受浏览器信任的证书。使用下面的 openssl 命令生成 CA 证书：

#一键回车
[root@node01 ~]# openssl req -newkey rsa:2048 -nodes -keyout tls.key -x509 -days 365 -out tls.crt
Generating a 2048 bit RSA private key
.....................................+++
.............................................................................+++
writing new private key to 'tls.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:
State or Province Name (full name) []:
Locality Name (eg, city) [Default City]:
Organization Name (eg, company) [Default Company Ltd]:
Organizational Unit Name (eg, section) []:
Common Name (eg, your name or your server's hostname) []:

现在我们有了证书，我们可以使用 kubectl 创建一个 secret 对象来存储上面的证书：

[root@node01 ~]# kubectl create secret generic traefik-cert --from-file=tls.crt --from-file=tls.key -n kube-system
secret "traefik-cert" created

[root@node01 ~]# mkdir /ssl
[root@node01 ~]# cp -a tls.* /ssl/
[root@node01 ~]# ls /ssl/
tls.crt  tls.key

2. 配置 Traefik

前面我们使用的是 Traefik 的默认配置，现在我们来配置 Traefik，让其支持 https：

[root@node01 ~]# vim traefik.toml
[root@node01 ~]# cat traefik.toml 
defaultEntryPoints = ["http", "https"]
[entryPoints]
  [entryPoints.http]
  address = ":80"
    [entryPoints.http.redirect]
      entryPoint = "https"
  [entryPoints.https]
  address = ":443"
    [entryPoints.https.tls]
      [[entryPoints.https.tls.certificates]]
      CertFile = "/ssl/tls.crt"
      KeyFile = "/ssl/tls.key"

[root@node01 ~]# mkdir /config
[root@node01 ~]# cp -a traefik.toml /config/

上面的配置文件中我们配置了 http 和 https 两个入口，并且配置了将 http 服务强制跳转到 https 服务，这样我们所有通过 traefik 进来的服务都是 https 的，要访问 https 服务，当然就得配置对应的证书了，可以看到我们指定了 CertFile 和 KeyFile 两个文件，由于 traefik pod 中并没有这两个证书，所以我们要想办法将上面生成的证书挂载到 Pod 中去，是不是前面我们讲解过 secret 对象可以通过 volume 形式挂载到 Pod 中？至于上面的 traefik.toml 这个文件我们要怎么让 traefik pod 能够访问到呢？还记得我们前面讲过的 ConfigMap 吗？我们是不是可以将上面的 traefik.toml 配置文件通过一个 ConfigMap 对象挂载到 traefik pod 中去：

[root@node01 ~]# kubectl create configmap traefik-conf --from-file=traefik.toml -n kube-system
configmap "traefik-conf" created

3. 使用 RBAC 安全认证方式

为安全起见我们这里使用 RBAC 安全认证方式：(rbac.yaml)：

[root@node01 ~]# vim rbac.yaml
[root@node01 ~]# cat rbac.yaml
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: traefik-ingress-controller
rules:
  - apiGroups:
      - ""
    resources:
      - services
      - endpoints
      - secrets
    verbs:
      - get
      - list
      - watch
  - apiGroups:
      - extensions
    resources:
      - ingresses
    verbs:
      - get
      - list
      - watch
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: traefik-ingress-controller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: traefik-ingress-controller
subjects:
- kind: ServiceAccount
  name: traefik-ingress-controller
  namespace: kube-system

直接在集群中创建即可：

[root@node01 ~]# kubectl create -f rbac.yaml
serviceaccount "traefik-ingress-controller" created
clusterrole.rbac.authorization.k8s.io "traefik-ingress-controller" created
clusterrolebinding.rbac.authorization.k8s.io "traefik-ingress-controller" created

4. 修改traefik pod 的 yaml 文件

现在就可以更改下上节课的 traefik pod 的 yaml 文件了：

[root@node01 ~]# vim traefik.yaml
[root@node01 ~]# cat traefik.yaml
kind: Deployment
apiVersion: apps/v1
metadata:
  name: traefik-ingress-controller
  namespace: kube-system
  labels:
    k8s-app: traefik-ingress-lb
spec:
  replicas: 1
  selector:
    matchLabels:
      k8s-app: traefik-ingress-lb
  template:
    metadata:
      labels:
        k8s-app: traefik-ingress-lb
        name: traefik-ingress-lb
    spec:
      serviceAccountName: traefik-ingress-controller
      terminationGracePeriodSeconds: 60
      volumes:
      - name: ssl
        secret:
          secretName: traefik-cert
      - name: config
        configMap:
          name: traefik-conf
      tolerations:
      - operator: "Exists"
      nodeSelector:
        kubernetes.io/hostname: master
      containers:
      - image: traefik:v1.7.17
        name: traefik-ingress-lb
        volumeMounts:
        - mountPath: "/ssl"
          name: "ssl"
        - mountPath: "/config"
          name: "config"
        ports:
        - name: http
          containerPort: 80
          hostPort: 80
        - name: https
          containerPort: 443
          hostPort: 443
        - name: admin
          containerPort: 8080
        args:
        - --configfile=/config/traefik.toml
        - --api
        - --kubernetes
        - --logLevel=INFO
---
kind: Service
apiVersion: v1
metadata:
  name: traefik-ingress-service
  namespace: kube-system
spec:
  selector:
    k8s-app: traefik-ingress-lb
  ports:
    - protocol: TCP
      port: 80
      name: web
    - protocol: TCP
      port: 8080
      name: admin
  type: NodePort

和之前的比较，我们增加了 443 的端口配置，以及启动参数中通过 configfile 指定了 traefik.toml 配置文件，这个配置文件是通过 volume 挂载进来的。然后更新下 traefik pod:

[root@node01 ~]# kubectl create -f traefik.yaml
deployment.apps "traefik-ingress-controller" created
service "traefik-ingress-service" created

5. 创建 ingress 对象

现在我们是通过 NodePort 来访问 traefik 的 Dashboard 的，那怎样通过 ingress 来访问呢？ 首先，需要创建一个 ingress 对象：(ingress.yaml)

[root@node01 ~]# vim ingress.yaml
[root@node01 ~]# cat ingress.yaml 
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: traefik-web-ui
  namespace: kube-system
  annotations:
    kubernetes.io/ingress.class: traefik
spec:
  rules:
  - host: traefik.haimaxy.com
    http:
      paths:
      - backend:
          serviceName: traefik-ingress-service
          servicePort: 8080

然后为 traefik dashboard 创建对应的 ingress 对象：

[root@node01 ~]# kubectl create -f ingress.yaml
ingress.extensions "traefik-web-ui" created

6. 验证

http://traefik.haimaxy.com