Service Fabric container networking modes

An Azure Service Fabric cluster for container services uses nat networking mode by default. When more than one container service is listening on the same port and nat mode is being used, deployment errors can occur. To support multiple container services listening on the same port, Service Fabric offers Open networking mode (versions 5.7 and later). In Open mode, each container service has an internal, dynamically assigned IP address that supports multiple services listening on the same port.

If you have one container service with a static endpoint in your service manifest, you can create and delete new services by using Open mode without deployment errors. The same docker-compose.yml file can also be used with static port mappings to create multiple services.

When a container service restarts or moves to another node in the cluster, the IP address changes. For this reason, we don't recommend using the dynamically assigned IP address to discover container services. Only the Service Fabric Naming Service or the DNS Service should be used for service discovery.

Warning

Azure allows a total of 4,096 IPs per virtual network. The sum of the number of nodes and the number of container service instances (that are using Open mode) can't exceed 4,096 IPs within a virtual network. For high-density scenarios, we recommend nat networking mode.

Set up Open networking mode

  1. Set up the Azure Resource Manager template. In the fabricSettings section of the Cluster resource, enable the DNS Service and the IP Provider:

    "fabricSettings": [
                {
                    "name": "DnsService",
                    "parameters": [
                       {
                            "name": "IsEnabled",
                            "value": "true"
                      }
                    ]
                },
                {
                    "name": "Hosting",
                    "parameters": [
                      { 
                            "name": "IPProviderEnabled",
                            "value": "true"
                      }
                    ]
                },
                {
                    "name":  "Trace/Etw", 
                    "parameters": [
                    {
                            "name": "Level",
                            "value": "5"
                    }
                    ]
                },
                {
                    "name": "Setup",
                    "parameters": [
                    {
                            "name": "ContainerNetworkSetup",
                            "value": "true"
                    }
                    ]
                }
            ],
    
  2. Set up the network profile section of the Virtual Machine Scale Set resource. This allows multiple IP addresses to be configured on each node of the cluster. The following example sets up five IP addresses per node for a Windows/Linux Service Fabric cluster. You can have five service instances listening on the port on each node. To have the five IPs be accessible from the Azure Load Balancer, enroll the five IPs in the Azure Load Balancer Backend Address Pool as shown below. You will also neeed to add the variables to the top of your template in the variables section.

    Add this section to Variables:

    "variables": {
        "nicName": "NIC",
        "vmName": "vm",
        "virtualNetworkName": "VNet",
        "vnetID": "[resourceId('Microsoft.Network/virtualNetworks',variables('virtualNetworkName'))]",
        "vmNodeType0Name": "[toLower(concat('NT1', variables('vmName')))]",
        "subnet0Name": "Subnet-0",
        "subnet0Prefix": "10.0.0.0/24",
        "subnet0Ref": "[concat(variables('vnetID'),'/subnets/',variables('subnet0Name'))]",
        "lbID0": "[resourceId('Microsoft.Network/loadBalancers',concat('LB','-', parameters('clusterName'),'-',variables('vmNodeType0Name')))]",
        "lbIPConfig0": "[concat(variables('lbID0'),'/frontendIPConfigurations/LoadBalancerIPConfig')]",
        "lbPoolID0": "[concat(variables('lbID0'),'/backendAddressPools/LoadBalancerBEAddressPool')]",
        "lbProbeID0": "[concat(variables('lbID0'),'/probes/FabricGatewayProbe')]",
        "lbHttpProbeID0": "[concat(variables('lbID0'),'/probes/FabricHttpGatewayProbe')]",
        "lbNatPoolID0": "[concat(variables('lbID0'),'/inboundNatPools/LoadBalancerBEAddressNatPool')]"
    }
    

    Add this section to the Virtual Machine Scale Set resource:

    "networkProfile": {
                "networkInterfaceConfigurations": [
                  {
                    "name": "[concat(parameters('nicName'), '-0')]",
                    "properties": {
                      "ipConfigurations": [
                        {
                          "name": "[concat(parameters('nicName'),'-',0)]",
                          "properties": {
                            "primary": "true",
                            "loadBalancerBackendAddressPools": [
                              {
                                "id": "[variables('lbPoolID0')]"
                              }
                            ],
                            "loadBalancerInboundNatPools": [
                              {
                                "id": "[variables('lbNatPoolID0')]"
                              }
                            ],
                            "subnet": {
                              "id": "[variables('subnet0Ref')]"
                            }
                          }
                        },
                        {
                          "name": "[concat(parameters('nicName'),'-', 1)]",
                          "properties": {
                            "primary": "false",
                            "loadBalancerBackendAddressPools": [
                              {
                                "id": "[variables('lbPoolID0')]"
                              }
                            ],
                            "subnet": {
                              "id": "[variables('subnet0Ref')]"
                            }
                          }
                        },
                        {
                          "name": "[concat(parameters('nicName'),'-', 2)]",
                          "properties": {
                            "primary": "false",
                            "loadBalancerBackendAddressPools": [
                              {
                                "id": "[variables('lbPoolID0')]"
                              }
                            ],
                            "subnet": {
                              "id": "[variables('subnet0Ref')]"
                            }
                          }
                        },
                        {
                          "name": "[concat(parameters('nicName'),'-', 3)]",
                          "properties": {
                            "primary": "false",
                            "loadBalancerBackendAddressPools": [
                              {
                                "id": "[variables('lbPoolID0')]"
                              }
                            ],
                            "subnet": {
                              "id": "[variables('subnet0Ref')]"
                            }
                          }
                        },
                        {
                          "name": "[concat(parameters('nicName'),'-', 4)]",
                          "properties": {
                            "primary": "false",
                            "loadBalancerBackendAddressPools": [
                              {
                                "id": "[variables('lbPoolID0')]"
                              }
                            ],
                            "subnet": {
                              "id": "[variables('subnet0Ref')]"
                            }
                          }
                        },
                        {
                          "name": "[concat(parameters('nicName'),'-', 5)]",
                          "properties": {
                            "primary": "false",
                            "loadBalancerBackendAddressPools": [
                              {
                                "id": "[variables('lbPoolID0')]"
                              }
                            ],
                            "subnet": {
                              "id": "[variables('subnet0Ref')]"
                            }
                          }
                        }
                      ],
                      "primary": true
                    }
                  }
                ]
              }
    
  3. For Windows clusters only, set up an Azure Network Security Group (NSG) rule that opens up port UDP/53 for the virtual network with the following values:

    Setting Value
    Priority 2000
    Name Custom_Dns
    Source VirtualNetwork
    Destination VirtualNetwork
    Service DNS (UDP/53)
    Action Allow
  4. Specify the networking mode in the application manifest for each service: <NetworkConfig NetworkType="Open">. Open networking mode results in the service getting a dedicated IP address. If a mode isn't specified, the service defaults to nat mode. In the following manifest example, the NodeContainerServicePackage1 and NodeContainerServicePackage2 services can each listen on the same port (both services are listening on Endpoint1). When Open networking mode is specified, PortBinding configurations cannot be specified.

    <?xml version="1.0" encoding="UTF-8"?>
    <ApplicationManifest ApplicationTypeName="NodeJsApp" ApplicationTypeVersion="1.0" xmlns="http://schemas.microsoft.com/2011/01/fabric" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
      <Description>Calculator Application</Description>
      <Parameters>
        <Parameter Name="ServiceInstanceCount" DefaultValue="3"></Parameter>
        <Parameter Name="MyCpuShares" DefaultValue="3"></Parameter>
      </Parameters>
      <ServiceManifestImport>
        <ServiceManifestRef ServiceManifestName="NodeContainerServicePackage1" ServiceManifestVersion="1.0"/>
        <Policies>
          <ContainerHostPolicies CodePackageRef="NodeContainerService1.Code" Isolation="hyperv">
           <NetworkConfig NetworkType="Open"/>
          </ContainerHostPolicies>
        </Policies>
      </ServiceManifestImport>
      <ServiceManifestImport>
        <ServiceManifestRef ServiceManifestName="NodeContainerServicePackage2" ServiceManifestVersion="1.0"/>
        <Policies>
          <ContainerHostPolicies CodePackageRef="NodeContainerService2.Code" Isolation="default">
            <NetworkConfig NetworkType="Open"/>
          </ContainerHostPolicies>
        </Policies>
      </ServiceManifestImport>
    </ApplicationManifest>
    

    You can mix and match different networking modes across services within an application for a Windows cluster. Some services can use Open mode while others use nat mode. When a service is configured to use nat mode, the port that the service is listening on must be unique.

    Note

    On Linux clusters, mixing networking modes for different services is not supported.

  5. When the Open mode is selected, the Endpoint definition in the service manifest should explicitly point to the code package corresponding to the endpoint, even if the service package has only one code package in it.

    <Resources>
      <Endpoints>
        <Endpoint Name="ServiceEndpoint" Protocol="http" Port="80" CodePackageRef="Code"/>
      </Endpoints>
    </Resources>
    
  6. For Windows, a VM reboot will cause the open network to be recreated. This is to mitigate an underlying issue in the networking stack. The default behaviour is to recreate the network. If this behaviour needs to be turned off, the following configuration can be used followed by a config upgrade.

"fabricSettings": [
                {
                    "name": "Setup",
                    "parameters": [
                    {
                            "name": "SkipContainerNetworkResetOnReboot",
                            "value": "true"
                    }
                    ]
                }
            ],          

Next steps