Use a Dedicated Health Endpoint for Front Door backends

Reliability · Front Door · 2021_03

Configure a dedicated path for health probe requests.

Description

Azure Front Door monitors a specific path for each backend to determine health status. The monitored path should implement functional checks to determine if the backend is performing correctly. The checks should include dependencies including those that may not be regularly called.

Regular checks of the monitored path allow Front Door to make load balancing decisions based on status.

Recommendation

Consider using a dedicated health probe endpoint that implements functional checks.

Examples

Configure with Azure template

Premium / StandardClassic

To deploy a Front Door resource that passes this rule:

• Set the properties.healthProbeSettings.probePath property to a dedicated path of the originGroups sub-resource.

For example:

Azure Template snippet

{
  "type": "Microsoft.Cdn/profiles",
  "apiVersion": "2021-06-01",
  "name": "[parameters('name')]",
  "location": "Global",
  "sku": {
    "name": "Premium_AzureFrontDoor"
  }
},
{
  "type": "Microsoft.Cdn/profiles/originGroups",
  "apiVersion": "2021-06-01",
  "name": "[format('{0}/{1}', parameters('name'), parameters('name'))]",
  "properties": {
    "loadBalancingSettings": {
      "sampleSize": 4,
      "successfulSamplesRequired": 3
    },
    "healthProbeSettings": {
      "probePath": "/healthz",
      "probeRequestType": "HEAD",
      "probeProtocol": "Http",
      "probeIntervalInSeconds": 100
    }
  },
  "dependsOn": [
    "[parameters('name')]"
  ]
}

To deploy a Front Door resource that passes this rule:

• Set each properties.healthProbeSettings[*].properties.path property to a dedicated path.

For example:

Azure Template snippet

{
  "type": "Microsoft.Network/frontDoors",
  "apiVersion": "2021-06-01",
  "name": "[parameters('name')]",
  "location": "global",
  "properties": {
    "enabledState": "Enabled",
    "frontendEndpoints": "[variables('frontendEndpoints')]",
    "loadBalancingSettings": "[variables('loadBalancingSettings')]",
    "backendPools": "[variables('backendPools')]",
    "healthProbeSettings": [
      {
        "name": "[variables('healthProbeSettingsName')]",
        "properties": {
          "enabledState": "Enabled",
          "path": "/healthz",
          "protocol": "Http",
          "intervalInSeconds": 120,
          "healthProbeMethod": "HEAD"
        }
      }
    ],
    "routingRules": "[variables('routingRules')]"
  }
}

Configure with Bicep

Premium / StandardClassic

To deploy a Front Door resource that passes this rule:

• Set the properties.healthProbeSettings.probePath property to a dedicated path of the originGroups sub-resource.

For example:

Azure Bicep snippet

resource afd_premium 'Microsoft.Cdn/profiles@2021-06-01' = {
  name: name
  location: 'Global'
  sku: {
    name: 'Premium_AzureFrontDoor'
  }
}

resource frontDoorOriginGroup 'Microsoft.Cdn/profiles/originGroups@2021-06-01' = {
  name: name
  parent: afd_premium
  properties: {
    loadBalancingSettings: {
      sampleSize: 4
      successfulSamplesRequired: 3
    }
    healthProbeSettings: {
      probePath: '/healthz'
      probeRequestType: 'HEAD'
      probeProtocol: 'Http'
      probeIntervalInSeconds: 100
    }
  }
}

To deploy a Front Door resource that passes this rule:

• Set each properties.healthProbeSettings[*].properties.path property to a dedicated path.

For example:

Azure Bicep snippet

resource afd_classic 'Microsoft.Network/frontDoors@2021-06-01' = {
  name: name
  location: 'global'
  properties: {
    enabledState: 'Enabled'
    frontendEndpoints: frontendEndpoints
    loadBalancingSettings: loadBalancingSettings
    backendPools: backendPools
    healthProbeSettings: [
      {
        name: healthProbeSettingsName
        properties: {
          enabledState: 'Enabled'
          path: '/healthz'
          protocol: 'Http'
          intervalInSeconds: 120
          healthProbeMethod: 'HEAD'
        }
      }
    ]
    routingRules: routingRules
  }
}

Configure with Azure CLI

Azure CLI snippet

az network front-door probe update --front-door-name '<front_door>' -n '<probe_name>' -g '<resource_group>' --path '/healthz'

Configure with Azure PowerShell

Azure PowerShell snippet

$probeSetting = New-AzFrontDoorHealthProbeSettingObject -Name '<probe_name>' -Path '/healthz'
Set-AzFrontDoor -Name '<front_door>' -ResourceGroupName '<resource_group>' -HealthProbeSetting $probeSetting

Links

• Creating good health probes
• Health probes
• Supported HTTP methods for health probes
• How Front Door determines backend health
• Health Endpoint Monitoring pattern
• Azure deployment reference (Premium / Standard)
• Azure deployment reference (Classic)

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Last update: 2023-02-18

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