Creating a High-Performance and Secure Azure Application Gateway

Azure Application Gateway is a fully managed service that provides high-performance and secure load balancing for web applications. It allows you to distribute incoming traffic across multiple backend servers, and it also provides features such as SSL offloading, cookie-based session affinity, and URL path-based routing.

Creating the Azure Application Gateway using Azure Portal

To create an Azure Application Gateway, you can use the Azure Portal, Azure PowerShell, or Azure CLI. In this article, we will go through the steps to create an Azure Application Gateway using the Azure Portal.

• Open the Azure Portal and navigate to the "Application Gateways" page.

• Click the "+ Create" button to create a new application gateway.

• Fill in the basic information for the application gateway, such as the name, subscription, resource group, and location.

• Select the appropriate size for the application gateway. The size determines the number of virtual CPUs and the amount of memory that the application gateway will have.

• Select the appropriate subnet for the application gateway. The subnet must be a subnet of an existing virtual network.

• Add the backend pool for the application gateway. The backend pool is a collection of servers that will receive the incoming traffic.

• Add the routing rules for the application gateway. The routing rules determine how the incoming traffic is distributed among the backend servers.

• Configure the health probes for the application gateway. The health probes are used to check the health of the backend servers, and they are used to determine which servers are available to receive traffic.

• Configure the SSL settings for the application gateway. This includes adding SSL certificates and configuring SSL offloading.

• Click the "Review + create" button to review the settings for the application gateway.

• Click the "Create" button to create the application gateway.

Once the application gateway is created, you can monitor and manage it using the Azure Portal, Azure PowerShell, or Azure CLI. You can also configure additional features such as URL path-based routing, cookie-based session affinity, and custom error pages.

Create the Azure Application Gateway using PowerShell

Creating an Azure Application Gateway using PowerShell is a similar process to creating one using the Azure Portal, but it allows you to automate the process using scripts. Here are the steps to create an Azure Application Gateway using PowerShell:

• First, you need to install the Azure PowerShell module. This can be done by running the command Install-Module -Name AzureRM in PowerShell.

• Next, you will need to log in to your Azure account by running the command Connect-AzAccount. This will prompt you to enter your Azure credentials.

• Create a new resource group for the application gateway by running the command New-AzResourceGroup -Name <resource-group-name> -Location <location>. Replace <resource-group-name> and <location> with the appropriate values for your application gateway.

• Create a new virtual network for the application gateway by running the command New-AzVirtualNetwork -Name <vnet-name> -ResourceGroupName <resource-group-name> -Location <location> -AddressPrefix <address-prefix>. Replace <vnet-name>, <resource-group-name>, <location>, and <address-prefix> with the appropriate values for your application gateway.

• Create a new subnet for the application gateway by running the command New-AzVirtualNetworkSubnetConfig -Name <subnet-name> -AddressPrefix <subnet-prefix> -VirtualNetwork <vnet-name>. Replace <subnet-name>, <subnet-prefix>, and <vnet-name> with the appropriate values for your application gateway.

• Create the application gateway by running the command New-AzApplicationGateway -Name <ag-name> -ResourceGroupName <resource-group-name> -Location <location> -BackendAddressPool <backend-address-pool> -BackendHttpSettings <http-settings> -GatewayIpConfig <ip-config> -FrontendIpConfig <frontend-ip-config> -FrontendPort <frontend-port> -HttpListener <http-listener> -Probe <probe> -RequestRoutingRule <request-routing-rule> -SslCert <ssl-cert>. Replace <ag-name>, <resource-group-name>, <location>, <backend-address-pool>, <http-settings>, <ip-config>, <frontend-ip-config>, <frontend-port>, <http-listener>, <probe>, <request-routing-rule>, and <ssl-cert> with the appropriate values for your application gateway.

• Verify that the application gateway has been created by running the command Get-AzApplicationGateway -Name <ag-name> -ResourceGroupName <resource-group-name>. Replace <ag-name> and <resource-group-name> with the appropriate values for your application gateway.

It's important to note that the above steps are a general overview of the process, the actual commands may vary depending on the specific requirements of the application gateway and the resources that you are creating. Also, you can use the Add-AzApplicationGateway* cmdlets to add features like routing rules and SSL certificates to the application gateway after creation.

In addition, it's also recommended to use a script or a configuration file where you can store the values for the different parameters, so you can easily modify and execute it as needed.

Creating an Azure Application Gateway using PowerShell allows you to automate the process, which can be useful for creating multiple application gateways or for provisioning the application gateway as part of a larger deployment process.

Here is the full PowerShell script that creates an Azure Application Gateway:

# Login to Azure
Connect-AzAccount

# Set variables for the application gateway
$resourceGroupName = "MyResourceGroup"
$agName = "MyAppGateway"
$location = "East US"
$vnetName = "MyVnet"
$subnetName = "MySubnet"
$subnetPrefix = "10.0.0.0/24"
$backendAddressPoolName = "MyBackendAddressPool"
$backendAddressPool = @{
    Name = $backendAddressPoolName
    BackendAddresses = @(
        @{
            IPAddress = "10.0.0.4"
        }
    )
}
$httpSettingsName = "MyHttpSettings"
$httpSettings = @{
    Name = $httpSettingsName
    Port = 80
    Protocol = "Http"
    CookieBasedAffinity = "Enabled"
}
$ipConfigName = "MyIpConfig"
$ipConfig = @{
    Name = $ipConfigName
    Subnet = @{
        Id = (Get-AzVirtualNetworkSubnetConfig -Name $subnetName -VirtualNetwork $vnetName).Id
    }
}
$frontendIpConfigName = "MyFrontendIpConfig"
$frontendIpConfig = @{
    Name = $frontendIpConfigName
    PublicIPAddress = @{
        Id = (New-AzPublicIpAddress -Name "MyPublicIp" -ResourceGroupName $resourceGroupName -Location $location -AllocationMethod Static).Id
    }
}
$frontendPortName = "MyFrontendPort"
$frontendPort = @{
    Name = $frontendPortName
    Port = 80
}
$httpListenerName = "MyHttpListener"
$httpListener = @{
    Name = $httpListenerName
    FrontendIPConfiguration = @{
        Id = $frontendIpConfig.Id
    }
    FrontendPort = @{
        Id = $frontendPort.Id
    }
    Protocol = "Http"
}
$probeName = "MyProbe"
$probe = @{
    Name = $probeName
    Protocol = "Http"
    Host = "www.contoso.com"
    Path = "/health"
    Interval = 30
    Timeout = 120
    UnhealthyThreshold = 3
}
$requestRoutingRuleName = "MyRequestRoutingRule"
$requestRoutingRule = @{
    Name = $requestRoutingRuleName
    RuleType = "Basic"
    HttpListener = @{
        Id = $httpListener.Id
    }
    BackendAddressPool = @{
        Id = $backendAddressPool.Id
    }
    BackendHttpSettings = @{
        Id = $httpSettings.Id
    }
}
$sslCertName = "MySslCert"
$sslCert = @{
    Name = $sslCertName
    Data = "-----BEGIN CERTIFICATE-----<YOUR CERTIFICATE DATA HERE>-----END CERTIFICATE-----"
    Password = "<YOUR CERTIFICATE PASSWORD HERE>"
}

# Create the application gateway
New-AzApplicationGateway -Name $agName -ResourceGroupName $resourceGroupName -Location $location -BackendAddressPools $backendAddressPool -BackendHttpSettings $httpSettings -GatewayIpConfig $ipConfig -FrontendIpConfigurations $frontendIpConfig -FrontendPorts $frontendPort -HttpListeners $httpListener -Probes $probe -RequestRoutingRules $requestRoutingRule -SslCertificates $sslCert

This script creates an application gateway with the specified settings, including a backend address pool, HTTP settings, IP configurations, frontend IP configurations, frontend ports, HTTP listeners, probes, request routing rules and SSL certificates.

It's important to note that this script is just an example and may not reflect the specific requirements of your use case. Additionally, you should replace the example values with your own values and make sure that the values you use are valid.

You can run this script in PowerShell and it will create an application gateway in your Azure subscription with the specified settings.

Final Words

In this article, you have learned how to use Azure Application Gateway to improve the performance and security of your web applications, and how to create an Azure Application Gateway using the Azure Portal and using PowerShell script. By following these simple steps, you can easily create an application gateway that meets the needs of your web application, and distribute the incoming traffic among multiple servers.