Chapter 11. Custom network interface templates

The default NIC templates might not suit a specific network configuration. For example, you might want to create your own custom NIC template that suits a specific network layout. You might want to separate the control services and data services on to separate NICs. In this situation, you can map the service to NIC assignments in the following way:

To simplify the configuration of custom interface templates, render the Jinja2 syntax of a default NIC template and use the rendered templates as the basis for your custom configuration.

The custom NIC templates that you render in Section 11.2, “Rendering default network interface templates for customization” contain the parameters and resources sections.

resources:
  OsNetConfigImpl:
    type: OS::Heat::SoftwareConfig
    properties:
      group: script
      config:
        str_replace:
          template:
            get_file: /usr/share/openstack-tripleo-heat-templates/network/scripts/run-os-net-config.sh
          params:
            $network_config:
              network_config:

This runs a script (run-os-net-config.sh) that creates a configuration file for os-net-config to use for configuring network properties on a node. The network_config section contains the custom network interface data sent to the run-os-net-config.sh script. You arrange this custom interface data in a sequence based on the type of device.

Network interface configuration contains the following parameters:

For example:

  - type: interface
    name: nic2

For example:

  - type: vlan
    vlan_id:{get_param: ExternalNetworkVlanID}
    addresses:
      - ip_netmask: {get_param: ExternalIpSubnet}

For example:

          - type: ovs_bond
            name: bond1
            members:
            - type: interface
              name: nic2
            - type: interface
              name: nic3

The network interface type, ovs_bridge, takes a parameter name.

If you are defining an OVS bridge for the external tripleo network, then retain the values bridge_name and interface_name as your deployment framework automatically replaces these values with an external bridge name and an external interface name, respectively.

For example:

      - type: ovs_bridge
        name: bridge_name
        addresses:
        - ip_netmask:
            list_join:
            - /
            - - {get_param: ControlPlaneIp}
              - {get_param: ControlPlaneSubnetCidr}
        members:
          - type: interface
            name: interface_name
      - type: vlan
        device: bridge_name
        vlan_id:
          {get_param: ExternalNetworkVlanID}
        addresses:
          - ip_netmask:
              {get_param: ExternalIpSubnet}

For example:

      - type: linux_bond
        name: bond1
        members:
        - type: interface
          name: nic2
          primary: true
        - type: interface
          name: nic3
        bonding_options: "mode=802.3ad"

Note that nic2 uses primary: true. This ensures the bond uses the MAC address for nic2.

For example:

      - type: linux_bridge
        name: bridge_name
        addresses:
          - ip_netmask:
              list_join:
                - /
                - - {get_param: ControlPlaneIp}
                  - {get_param: ControlPlaneSubnetCidr}
        members:
          - type: interface
            name: interface_name
      - type: vlan
        device: bridge_name
        vlan_id:
          {get_param: ExternalNetworkVlanID}
        addresses:
          - ip_netmask:
              {get_param: ExternalIpSubnet}

For example:

  - type: interface
    name: nic2
    ...
    routes:
      - ip_netmask: 10.1.2.0/24
        default: true
        next_hop:
          get_param: EC2MetadataIp

The following snippet for an example Controller node NIC template demonstrates how to configure the custom network scenario to keep the control group separate from the OVS bridge:

resources:
  OsNetConfigImpl:
    type: OS::Heat::SoftwareConfig
    properties:
      group: script
      config:
        str_replace:
          template:
            get_file: /usr/share/openstack-tripleo-heat-templates/network/scripts/run-os-net-config.sh
          params:
            $network_config:
              network_config:

              # NIC 1 - Provisioning
              - type: interface
                name: nic1
                use_dhcp: false
                addresses:
                - ip_netmask:
                    list_join:
                    - /
                    - - get_param: ControlPlaneIp
                      - get_param: ControlPlaneSubnetCidr
                routes:
                - ip_netmask: 169.254.169.254/32
                  next_hop:
                    get_param: EC2MetadataIp

              # NIC 2 - Control Group
              - type: interface
                name: nic2
                use_dhcp: false
              - type: vlan
                device: nic2
                vlan_id:
                  get_param: InternalApiNetworkVlanID
                addresses:
                - ip_netmask:
                    get_param: InternalApiIpSubnet
              - type: vlan
                device: nic2
                vlan_id:
                  get_param: StorageMgmtNetworkVlanID
                addresses:
                - ip_netmask:
                    get_param: StorageMgmtIpSubnet
              - type: vlan
                device: nic2
                vlan_id:
                  get_param: ExternalNetworkVlanID
                addresses:
                - ip_netmask:
                    get_param: ExternalIpSubnet
                routes:
                - default: true
                  next_hop:
                    get_param: ExternalInterfaceDefaultRoute

              # NIC 3 - Data Group
              - type: ovs_bridge
                name: bridge_name
                dns_servers:
                  get_param: DnsServers
                members:
                - type: interface
                  name: nic3
                  primary: true
                - type: vlan
                  vlan_id:
                    get_param: StorageNetworkVlanID
                  addresses:
                  - ip_netmask:
                      get_param: StorageIpSubnet
                - type: vlan
                  vlan_id:
                    get_param: TenantNetworkVlanID
                  addresses:
                  - ip_netmask:
                      get_param: TenantIpSubnet

                # NIC 4 - Management
                - type: interface
                  name: nic4
                  use_dhcp: false
                  addresses:
                  - ip_netmask: {get_param: ManagementIpSubnet}
                  routes:
                  - default: true
                    next_hop: {get_param: ManagementInterfaceDefaultRoute}

This template uses four network interfaces and assigns a number of tagged VLAN devices to the numbered interfaces, nic1 to nic4. On nic3 it creates the OVS bridge that hosts the Storage and Tenant networks. As a result, it creates the following layout:

When you use composable networks, the process-templates.py script renders the static templates to include networks and roles that you define in your network_data.yaml and roles_data.yaml files. Ensure that your rendered NIC templates contain the following items:

Each static file requires all the parameter definitions for any custom networks even if the network is not used on the role. Check to make sure the rendered templates contain these parameters. For example, if a StorageBackup network is added to only the Ceph nodes, the parameters section in NIC configuration templates for all roles must also include this definition:

parameters:
  ...
  StorageBackupIpSubnet:
    default: ''
    description: IP address/subnet on the external network
    type: string
  ...

You can also include the parameters definitions for VLAN IDs and/or gateway IP, if needed:

parameters:
  ...
  StorageBackupNetworkVlanID:
    default: 60
    description: Vlan ID for the management network traffic.
    type: number
  StorageBackupDefaultRoute:
	  description: The default route of the storage backup network.
	  type: string
  ...

The IpSubnet parameter for the custom network appears in the parameter definitions for each role. However, since the Ceph role might be the only role that uses the StorageBackup network, only the NIC configuration template for the Ceph role would make use of the StorageBackup parameters in the network_config section of the template.

      $network_config:
        network_config:
        - type: interface
          name: nic1
          use_dhcp: false
          addresses:
          - ip_netmask:
              get_param: StorageBackupIpSubnet

The custom network environment file (in this case, /home/stack/templates/custom-network-configuration.yaml) is a heat environment file that describes the overcloud network environment and points to the custom network interface configuration templates. You can define the subnets and VLANs for your network along with IP address ranges. You can then customize these values for the local environment.

The resource_registry section contains references to the custom network interface templates for each node role. Each resource registered uses the following format:

[ROLE] is the role name and [FILE] is the respective network interface template for that particular role. For example:

resource_registry:
  OS::TripleO::Controller::Net::SoftwareConfig: /home/stack/templates/custom-nics/controller.yaml

The parameter_defaults section contains a list of parameters that define the network options for each network type.

The following table is a list of parameters that you can use in the parameter_defaults section of a network environment file to override the default parameter values in your NIC templates.

The following snippet is an example of an environment file that you can use to enable your NIC templates and set custom parameters.

resource_registry:
  OS::TripleO::BlockStorage::Net::SoftwareConfig:
    /home/stack/templates/nic-configs/cinder-storage.yaml
  OS::TripleO::Compute::Net::SoftwareConfig:
    /home/stack/templates/nic-configs/compute.yaml
  OS::TripleO::Controller::Net::SoftwareConfig:
    /home/stack/templates/nic-configs/controller.yaml
  OS::TripleO::ObjectStorage::Net::SoftwareConfig:
    /home/stack/templates/nic-configs/swift-storage.yaml
  OS::TripleO::CephStorage::Net::SoftwareConfig:
    /home/stack/templates/nic-configs/ceph-storage.yaml

parameter_defaults:
  # Gateway router for the provisioning network (or Undercloud IP)
  ControlPlaneDefaultRoute: 192.0.2.254
  # The IP address of the EC2 metadata server. Generally the IP of the Undercloud
  EC2MetadataIp: 192.0.2.1
  # Define the DNS servers (maximum 2) for the overcloud nodes
  DnsServers: ["8.8.8.8","8.8.4.4"]
  NeutronExternalNetworkBridge: "''"

To deploy the overcloud with network isolation and custom NIC templates, include all of the relevant networking environment files in the overcloud deployment command.

For example:

$ openstack overcloud deploy --templates \
    ...
    -n /home/stack/network_data.yaml \
    -e /usr/share/openstack-tripleo-heat-templates/environments/network-isolation.yaml \
    -e /usr/share/openstack-tripleo-heat-templates/environments/network-environment.yaml \
    -e /home/stack/templates/custom-network-configuration.yaml \
    ...