App Gateway(AGIC)应该指向Kubernetes Service而不是Pod。解决方法是，在Kubernetes环境中创建一个Service并将它绑定到App gateway上。具体实现可参考以下代码示例：

1. 部署一个示例应用程序

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: sample-app
  template:
    metadata:
      labels:
        app: sample-app
    spec:
      containers:
      - name: sample-app
        image: mcr.microsoft.com/oss/nginx/nginx:1.17.9-alpine
        ports:
        - containerPort: 80

2. 创建一个Service

apiVersion: v1
kind: Service
metadata:
  name: sample-app-service
spec:
  selector:
    app: sample-app
  ports:
    - name: http
      port: 80
      targetPort: 80

3. 配置App Gateway

创建一个App Gateway，将它配置为使用已创建的sample-app-service。以下是App Gateway配置文件的示例：

{
  "type": "Microsoft.Network/applicationGateways",
  "name": "myAppGateway",
  "location": "[resourceGroup().location]",
  "properties": {
      "sku": {
        "name": "WAF_Medium",
        "tier": "WAF",
        "capacity": 2
      },
      "gatewayIPConfigurations": [
        {
          "name": "myAppGatewayIpConfig",
          "properties": {
            "subnet": {
              "id": "[resourceId('Microsoft.Network/virtualNetworks/subnets', variables('virtualNetworkName'), variables('subnetName'))]"
            }
          }
        }
      ],
      "frontendIPConfigurations": [
        {
          "name": "myFrontendIp",
          "properties": {
            "privateIPAllocationMethod": "Dynamic",
            "subnet": {
              "id": "[resourceId('Microsoft.Network/virtualNetworks/subnets', variables('virtualNetworkName'), variables('subnetName'))]"
            }
          }
        }
      ],
      "frontendPorts": [
        {
          "name": "myFrontendHttpPort",
          "properties": {
            "Port": 80
          }
        }
      ],
      "backendAddressPools": [
        {
          "name": "myBackendAddressPool",
          "properties": {
            "BackendAddresses": [
              {
                "fqdn": "[concat('sample-app-service.default.svc.cluster.local:', '80')]"
              }
            ]
          }
        }
      ],
      "backendHttpSettingsCollection": [
        {
          "name": "myBackendHttpSettings",
          "properties": {
            "Port": 80,
            "Protocol": "Http",
            "CookieBasedAffinity": "Disabled"
          }
        }
      ],
      "httpListeners": [
        {
          "name": "myHttpListener",
          "properties": {
            "FrontendIPConfiguration": {
              "id": "[concat(resourceGroupId('Microsoft.Network/applicationGateways'), '/frontendIPConfigurations/', 'myFrontendIp')]"
            },
            "FrontendPort": {
              "id": "[concat(resourceGroupId('Microsoft.Network/applicationGateways'), '/frontendPorts/', 'myFrontendHttpPort')]"
            },
            "Protocol": "Http",
            "SslCertificate