EKS：如何在eks cloudmap中注册动态生成的eks负载均衡器dns？

Question

我有一个我使用过的kafka外部服务type: Loadbalancer

问题：此服务将始终在卸载/删除后创建新的负载均衡器。

用例：我想在 AWS 云图中针对一个 static DNS 注册负载均衡器的 dns。

apiVersion: v1
kind: Service
metadata:
  annotations:
    service.beta.kubernetes.io/aws-load-balancer-backend-protocol: tcp
    service.beta.kubernetes.io/aws-load-balancer-connection-idle-timeout: "60"
    service.beta.kubernetes.io/aws-load-balancer-cross-zone-load-balancing-enabled: "true"
    service.beta.kubernetes.io/aws-load-balancer-internal: "true"
    service.beta.kubernetes.io/aws-load-balancer-type: nlb
  name: kafka-test-3-1-external
  labels:
    helm.sh/chart: kafka-0.21.5
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/component: kafka-broker
    app.kubernetes.io/name: kafka
    app.kubernetes.io/instance: kafka-test-3
    pod: "kafka-test-3-1"
spec:
  type: LoadBalancer
  ports:
    - name: external-broker
      port: 19092
      targetPort: 19092
      protocol: TCP
#
  selector:
    app.kubernetes.io/component: kafka-broker
    app.kubernetes.io/name: kafka
    app.kubernetes.io/instance: kafka-test-3
    statefulset.kubernetes.io/pod-name: "kafka-test-3-1"

我怎样才能做到这一点？

Answer 1

您可以在服务中使用以下注释

external-dns.alpha.kubernetes.io/hostname: "kafka-test-3-1.kafka.internal"
external-dns.alpha.kubernetes.io/ttl: "60"

其中kafka.internal是我的云地图命名空间。

所以服务看起来像下面的代码片段。

apiVersion: v1
kind: Service
metadata:
  annotations:
    external-dns.alpha.kubernetes.io/hostname: "kafka-test-3-1.kafka.internal"
    external-dns.alpha.kubernetes.io/ttl: "60"
    service.beta.kubernetes.io/aws-load-balancer-backend-protocol: tcp
    service.beta.kubernetes.io/aws-load-balancer-connection-idle-timeout: "60"
    service.beta.kubernetes.io/aws-load-balancer-cross-zone-load-balancing-enabled: "true"
    service.beta.kubernetes.io/aws-load-balancer-internal: "true"
    service.beta.kubernetes.io/aws-load-balancer-type: nlb
  name: kafka-test-3-1-external
  labels:
    helm.sh/chart: kafka-0.21.5
    app.kubernetes.io/managed-by: Helm
    app.kubernetes.io/component: kafka-broker
    app.kubernetes.io/name: kafka
    app.kubernetes.io/instance: kafka-test-3
    pod: "kafka-test-3-1"
spec:
  type: LoadBalancer
  ports:
    - name: external-broker
      port: 19092
      targetPort: 19092
      protocol: TCP
#
  selector:
    app.kubernetes.io/component: kafka-broker
    app.kubernetes.io/name: kafka
    app.kubernetes.io/instance: kafka-test-3
    statefulset.kubernetes.io/pod-name: "kafka-test-3-1"

要将服务负载均衡器的 dns 注册到 cloud-map，我们需要使用external-dns服务。

注意：您必须在 cloudmap 中创建命名空间。 并为您的 kubernetes 用户提供足够的访问权限。

要使用 AWS 云 Map API，用户必须有权创建 DNS 命名空间。 此外，您需要确保您的节点（External DNS 在其上运行）具有附加了AWSCloudMapFullAccess托管策略的 IAM 实例配置文件，该配置文件提供以下权限：

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": [
        "route53:GetHostedZone",
        "route53:ListHostedZonesByName",
        "route53:CreateHostedZone",
        "route53:DeleteHostedZone",
        "route53:ChangeResourceRecordSets",
        "route53:CreateHealthCheck",
        "route53:GetHealthCheck",
        "route53:DeleteHealthCheck",
        "route53:UpdateHealthCheck",
        "ec2:DescribeVpcs",
        "ec2:DescribeRegions",
        "servicediscovery:*"
      ],
      "Resource": [
        "*"
      ]
    }
  ]
}

在应用以下代码段之前，请替换占位符

• YOUR_NAMESPACE ：使用您的 kubernetes 的集群命名空间，如默认值
• AWS_REGION_VALUE ：ap-south-1
• DOMAIN_FILTER ：它必须是您的云图命名空间的名称。 就我而言，它将是kafka.internal

片段：外部DNS

apiVersion: v1
kind: ServiceAccount
metadata:
  name: external-dns
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRole
metadata:
  name: external-dns
rules:
- apiGroups: [""]
  resources: ["services","endpoints","pods"]
  verbs: ["get","watch","list"]
- apiGroups: ["extensions","networking.k8s.io"]
  resources: ["ingresses"]
  verbs: ["get","watch","list"]
- apiGroups: [""]
  resources: ["nodes"]
  verbs: ["list","watch"]
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
  name: external-dns-viewer
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: external-dns
subjects:
- kind: ServiceAccount
  name: external-dns
  namespace: YOUR_NAMESPACE
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: external-dns
spec:
  strategy:
    type: Recreate
  selector:
    matchLabels:
      app: external-dns
  template:
    metadata:
      labels:
        app: external-dns
    spec:
      serviceAccountName: external-dns
      containers:
      - name: external-dns
        image: k8s.gcr.io/external-dns/external-dns:v0.7.6
        env:
          - name: AWS_REGION
            value: AWS_REGION_VALUE # ap-south-1 put your CloudMap NameSpace region
        args:
        - --source=service
        - --source=ingress
        - --domain-filter=DOMAIN_FILTER # Makes ExternalDNS see only the namespaces that match the specified domain. Omit the filter if you want to process all available namespaces.
        - --provider=aws-sd
        - --aws-zone-type=private # Only look at public namespaces. Valid values are public, private, or no value for both)
        - --txt-owner-id=kafka-identifier

External-dns pod will polling for changes in kubernetes services and if find any changes it will use external-dns.alpha.kubernetes.io/hostname annotation to map that loadbalancer's dns into cloud-map namespaces.

有关自动注册的更多详细信息， https://github.com/kubernetes-sigs/external-dns/blob/master/docs/tutorials/aws-sd.md