3. 服务发现

3.1 设置Pod的hostname与subdomain

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# 编写Yaml文件
apiVersion: v1
kind: Service
metadata:
  name: default-subdomain
spec:
  selector:
    app: nginx
  clusterIP: None
  ports:
  - name: nginx
    port: 80
    targetPort: 80
---
apiVersion: v1
kind: Pod
metadata:
  name: nginx-hostname
  labels:
    app: nginx
spec:
  hostname: nginx-1
  subdomain: default-subdomain
  containers:
  - image: nginx
    name: nginx
    imagePullPolicy: IfNotPresent

解析Service Name

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# 创建busybox应用
kubectl run busybox --image=busybox:1.28 --image-pull-policy=IfNotPresent --command sleep 36000

# 执行解析操作
kubectl exec -it busybox -- nslookup default-subdomain

查看node的角色

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kubectl get nodes

3.2 HostAliases

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# 编写Yaml文件
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: deployment-nginx
spec:
  replicas: 4
  selector:
    matchLabels:
      app: pod-nginx
  template:
    metadata:
      labels:
        app: pod-nginx
    spec:
      hostAliases:
      - ip: "127.0.0.1"
        hostnames:
        - "foo.local"
        - "bar.local"
      - ip: "10.1.2.3"
        hostnames:
        - "foo.remote"
        - "bar.remote"
      containers:
      - name: nginx
        image: nginx:1.7.6
        ports:
        - containerPort: 80

3.3 Pod的DNS设置

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# 编写Yaml文件
apiVersion: v1
kind: Pod
metadata:
  namespace: default
  name: dns-example
spec:
  containers:
    - name: test
      image: nginx
  dnsPolicy: "None"
  dnsConfig:
    nameservers:
      - 1.2.3.4
    searches:
      - ns1.svc.cluster-domain.example
      - my.dns.search.suffix
    options:
      - name: ndots
        value: "2"
      - name: edns0
      
# 在容器test的/etc/resolv.conf文件中获取以下内容
nameserver 1.2.3.4
search ns1.svc.cluster-domain.example my.dns.search.suffix
options ndots:2 edns0