Kubernetes集群添加主机名解析

在Kubernetes集群中添加主机名解析分以下几种情况：

• 单个Pod添加直接主机别名
• 在CoreDNS添加主机名解析

1、pod中配置hosts解析域名

编辑deployment.yaml

apiVersion: apps/v1beta2
kind: Deployment
metadata:
  annotations:
    deployment.kubernetes.io/revision: "2"
  creationTimestamp: "2020-09-11T08:35:00Z"
  generation: 2
  labels:
    k8s-app: nginx-hosts-alis
    qcloud-app: nginx-hosts-alis
  name: nginx-hosts-alis
  namespace: test
  resourceVersion: "12673987137"
  selfLink: /apis/apps/v1beta2/namespaces/test/deployments/nginx-hosts-alis
  uid: 61493e8e-b0c9-4b5d-a031-6ea2799e9de8
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      k8s-app: nginx-hosts-alis
      qcloud-app: nginx-hosts-alis
  strategy:
    rollingUpdate:
      maxSurge: 1
      maxUnavailable: 0
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        k8s-app: nginx-hosts-alis
        qcloud-app: nginx-hosts-alis
    spec:
      containers:
      - image: nginx
        imagePullPolicy: Always
        name: nginx-hosts-alis
        resources:
          limits:
            cpu: 500m
            memory: 1Gi
          requests:
            cpu: 250m
            memory: 256Mi
        securityContext:
          privileged: false
        terminationMessagePath: /dev/termination-log
        terminationMessagePolicy: File
      dnsPolicy: ClusterFirst
      hostAliases:
      - hostnames:
        - foo.local
        - bar.local
        ip: 127.0.0.1
      - hostnames:
        - foo.remote
        - bar.remote
        ip: 10.1.2.3
      restartPolicy: Always
      schedulerName: default-scheduler
      securityContext: {}
      terminationGracePeriodSeconds: 30

2、CoreDNS添加主机名解析

如果node本地有dns插件，如NodeLocalDNS，需要先对NodeLocalDNS进行转发。比如域名解析出来的ip为169.254.25.10，需要将此请求现转发到coredns中，以coredns ip10.233.0.3为例，如下：

apiVersion: v1
kind: ConfigMap
metadata:
  creationTimestamp: "2024-09-15T01:02:02Z"
  labels:
    addonmanager.kubernetes.io/mode: EnsureExists
  name: nodelocaldns
  namespace: kube-system
  resourceVersion: "55695455"
  uid: 8b2c7245-6563-4a5f-bb11-cbdc5bb9e17c
data:
  Corefile: |
    cluster.local:53 {
        errors
        cache {
            success 9984 30
            denial 9984 5
        }
        reload
        loop
        bind 169.254.25.10
        forward . 10.233.0.3 {
            force_tcp
        }
        prometheus :9253
        health 169.254.25.10:9254
    }
    in-addr.arpa:53 {
        errors
        cache 30
        reload
        loop
        bind 169.254.25.10
        forward . 10.233.0.3 {
            force_tcp
        }
        prometheus :9253
    }
    ip6.arpa:53 {
        errors
        cache 30
        reload
        loop
        bind 169.254.25.10
        forward . 10.233.0.3 {
            force_tcp
        }
        prometheus :9253
    }
    .:53 {
        errors
        cache 30
        reload
        loop
        bind 169.254.25.10
        forward . 10.233.0.3 {
            force_tcp
        }
        prometheus :9253
    }

CoreDNS配置添加hosts主机名解析。

apiVersion: v1
kind: ConfigMap
metadata:
  creationTimestamp: "2024-09-15T01:01:58Z"
  labels:
    addonmanager.kubernetes.io/mode: EnsureExists
  name: coredns
  namespace: kube-system
  resourceVersion: "55644208"
  uid: 7e4fb70b-bac6-4c13-ad1a-8e9c0dbc0861
data:
  Corefile: |
    .:53 {
        errors
        health {
          lameduck 5s
        }
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
          pods insecure
          fallthrough in-addr.arpa ip6.arpa
        }
        hosts {
          10.65.10.91 jingxiang.oss-cn-lasa-xzns-d01-a.ops.sukai.com.cn
          10.65.10.91 oss-cn-lasa-xzns-d01-a.ops.sukai.com.cn
          fallthrough
        }
        prometheus :9153
        forward . 114.114.114.114 {
          prefer_udp
          max_concurrent 1000
        }
        cache 30
        loop
        reload
        loadbalance
    }