Manage an application gateway

Abstract

Learn how to configure an application gateway, monitor its health, and configure the public DNS server.

You use Application Gateway to ensure HTTP load balancing and secure your web applications. you can access information that helps you to monitor your resources, such as, back-end health, diagnostic logs, and metrics for the application gateway.

However, there are a few restrictions:

  • In the App Service environment, the certificate signing request feature is not supported and therefore you cannot reach:

    • The Universal Tracker outside of the ASE virtual network.

    • The XConnect client outside of the ASE virtual network.

  • In the web application, web sockets are turned off by default.

To configure an application gateway:

  1. In Application Gateway resource group, Application Gateway, HTTP settings, click appGatewayBackendHttpSettings.

  2. In the Azure portal, in the Application Gateway resource group, go to Application Gateway, Settings, Backend pools, and set the internal load balancer (ILB) as the backend server for Application Gateway.

    BackendPools.png
  3. To open the backend pool setting for Application Gateway, click appGatewayBackendPool.

    EditBackendPool.png
  4. In Edit backend pool, in the Name field, enter the fully qualified domain name for the Content Delivery Web App and then click Save.

  5. To configure the custom health probe that the appGatewayBackendPool uses, go to Application Gateway, Settings, Health probes, and click Add.

    Health_probes.png
  6. On the Add health probe page, specify the following fields:

    • Name

    • Protocol - To check the end-to-end health through the HTTPS channel, you must select HTTPS.

    • Pick host name from backend http settings - Select this check box.

    • Path - Set this to the root /

    • Interval (seconds) - Use the default value 30.

    • Timeout (seconds) - To avoid timeout errors, set the value to 180.

    • Unhealthy threshold - Use the default value 3.

    Add_health_probe.png

To configure the HTTP settings for Application Gateway:

  1. In the Application Gateway resource group, Application Gateway, HTTP settings, click appGatewayBackendHttpSettings.

    applicationgatewaywaf_-_HTTP_settings.png
  2. In the appGatewayBackendHttpSettings panel, in the Protocol field, click HTTPS.

    appGatewayBackendHttpSettings.png
  3. In the Backend authentication certificate section, enter the name of the certificate and upload it in CER format.

  4. Ensure that the Use for App service check box is not selected.

  5. Select the Use custom probe check box.

  6. In the Custom probe field, select the custom health probe that you created on the Add health probe page. In this example, https.

  7. Select the Pick hostname from backend address check box and save.

You have now finished editing the HTTP settings.

To use the WebApp to check the health of the application gateway connection.

  • Go to Application Gateway and open the Backend health page.

Backend health

The status of the health probe that you just created should be Healthy.

To configure the public DNS server:make the CD WebApp publicly available, you must ensure that the CNAME public domain name points to the Application Gateway public IP address.

  1. Find the Application Gateway Frontend public IP address, by going to Application Gateway resource group, select the Application Gateway resource from the list, and then open the Overview page.

    IPaddresses.png
  2. Use the value in the Frontend public IP address field to configure the CNAME record for the public DNS server.