Networking Option 2: Self-service networks

Networking Option 2: Self-service networks

Install and configure the Networking components on the controller node.

Install the components

# apt-get install neutron-server neutron-plugin-ml2 \
  neutron-plugin-linuxbridge-agent neutron-l3-agent neutron-dhcp-agent \
  neutron-metadata-agent python-neutronclient conntrack

Configure the server component

  • Edit the /etc/neutron/neutron.conf file and complete the following actions:

    • In the [database] section, configure database access:

      [database]
      ...
      connection = mysql+pymysql://neutron:NEUTRON_DBPASS@controller/neutron
      

      Replace NEUTRON_DBPASS with the password you chose for the database.

    • In the [DEFAULT] section, enable the Modular Layer 2 (ML2) plug-in, router service, and overlapping IP addresses:

      [DEFAULT]
      ...
      core_plugin = ml2
      service_plugins = router
      allow_overlapping_ips = True
      
    • In the [DEFAULT] and [oslo_messaging_rabbit] sections, configure RabbitMQ message queue access:

      [DEFAULT]
      ...
      rpc_backend = rabbit
      
      [oslo_messaging_rabbit]
      ...
      rabbit_host = controller
      rabbit_userid = openstack
      rabbit_password = RABBIT_PASS
      

      Replace RABBIT_PASS with the password you chose for the openstack account in RabbitMQ.

    • In the [DEFAULT] and [keystone_authtoken] sections, configure Identity service access:

      [DEFAULT]
      ...
      auth_strategy = keystone
      
      [keystone_authtoken]
      ...
      auth_uri = http://controller:5000
      auth_url = http://controller:35357
      auth_plugin = password
      project_domain_id = default
      user_domain_id = default
      project_name = service
      username = neutron
      password = NEUTRON_PASS
      

      Replace NEUTRON_PASS with the password you chose for the neutron user in the Identity service.

      Note

      Comment out or remove any other options in the [keystone_authtoken] section.

    • In the [DEFAULT] and [nova] sections, configure Networking to notify Compute of network topology changes:

      [DEFAULT]
      ...
      notify_nova_on_port_status_changes = True
      notify_nova_on_port_data_changes = True
      nova_url = http://controller:8774/v2
      
      [nova]
      ...
      auth_url = http://controller:35357
      auth_plugin = password
      project_domain_id = default
      user_domain_id = default
      region_name = RegionOne
      project_name = service
      username = nova
      password = NOVA_PASS
      

      Replace NOVA_PASS with the password you chose for the nova user in the Identity service.

    • (Optional) To assist with troubleshooting, enable verbose logging in the [DEFAULT] section:

      [DEFAULT]
      ...
      verbose = True
      

Configure the Modular Layer 2 (ML2) plug-in

The ML2 plug-in uses the Linux bridge mechanism to build layer-2 (bridging and switching) virtual networking infrastructure for instances.

  • Edit the /etc/neutron/plugins/ml2/ml2_conf.ini file and complete the following actions:

    • In the [ml2] section, enable flat, VLAN, and VXLAN networks:

      [ml2]
      ...
      type_drivers = flat,vlan,vxlan
      
    • In the [ml2] section, enable VXLAN project (private) networks:

      [ml2]
      ...
      tenant_network_types = vxlan
      
    • In the [ml2] section, enable the Linux bridge and layer-2 population mechanisms:

      [ml2]
      ...
      mechanism_drivers = linuxbridge,l2population
      

      Warning

      After you configure the ML2 plug-in, removing values in the type_drivers option can lead to database inconsistency.

      Note

      The Linux bridge agent only supports VXLAN overlay networks.

    • In the [ml2] section, enable the port security extension driver:

      [ml2]
      ...
      extension_drivers = port_security
      
    • In the [ml2_type_flat] section, configure the public flat provider network:

      [ml2_type_flat]
      ...
      flat_networks = public
      
    • In the [ml2_type_vxlan] section, configure the VXLAN network identifier range for private networks:

      [ml2_type_vxlan]
      ...
      vni_ranges = 1:1000
      
    • In the [securitygroup] section, enable ipset to increase efficiency of security group rules:

      [securitygroup]
      ...
      enable_ipset = True
      

Configure the Linux bridge agent

The Linux bridge agent builds layer-2 (bridging and switching) virtual networking infrastructure for instances including VXLAN tunnels for private networks and handles security groups.

  • Edit the /etc/neutron/plugins/ml2/linuxbridge_agent.ini file and complete the following actions:

    • In the [linux_bridge] section, map the public virtual network to the public physical network interface:

      [linux_bridge]
      physical_interface_mappings = public:PUBLIC_INTERFACE_NAME
      

      Replace PUBLIC_INTERFACE_NAME with the name of the underlying physical public network interface.

    • In the [vxlan] section, enable VXLAN overlay networks, configure the IP address of the physical network interface that handles overlay networks, and enable layer-2 population:

      [vxlan]
      enable_vxlan = True
      local_ip = OVERLAY_INTERFACE_IP_ADDRESS
      l2_population = True
      

      Replace OVERLAY_INTERFACE_IP_ADDRESS with the IP address of the underlying physical network interface that handles overlay networks. The example architecture uses the management interface to tunnel traffic to the other nodes. Therefore, replace OVERLAY_INTERFACE_IP_ADDRESS with each node’s own management IP address.

    • In the [agent] section, enable ARP spoofing protection:

      [agent]
      ...
      prevent_arp_spoofing = True
      
    • In the [securitygroup] section, enable security groups and configure the Linux bridge iptables firewall driver:

      [securitygroup]
      ...
      enable_security_group = True
      firewall_driver = neutron.agent.linux.iptables_firewall.IptablesFirewallDriver
      

Configure the layer-3 agent

The Layer-3 (L3) agent provides routing and NAT services for virtual networks.

  • Edit the /etc/neutron/l3_agent.ini file and complete the following actions:

    • In the [DEFAULT] section, configure the Linux bridge interface driver and external network bridge:

      [DEFAULT]
      ...
      interface_driver = neutron.agent.linux.interface.BridgeInterfaceDriver
      external_network_bridge =
      

      Note

      The external_network_bridge option intentionally lacks a value to enable multiple external networks on a single agent.

    • (Optional) To assist with troubleshooting, enable verbose logging in the [DEFAULT] section:

      [DEFAULT]
      ...
      verbose = True
      

Configure the DHCP agent

The DHCP agent provides DHCP services for virtual networks.

  • Edit the /etc/neutron/dhcp_agent.ini file and complete the following actions:

    • In the [DEFAULT] section, configure the Linux bridge interface driver, Dnsmasq DHCP driver, and enable isolated metadata so instances on public networks can access metadata over the network:

      [DEFAULT]
      ...
      interface_driver = neutron.agent.linux.interface.BridgeInterfaceDriver
      dhcp_driver = neutron.agent.linux.dhcp.Dnsmasq
      enable_isolated_metadata = True
      
    • (Optional) To assist with troubleshooting, enable verbose logging in the [DEFAULT] section:

      [DEFAULT]
      ...
      verbose = True
      

    Overlay networks such as VXLAN include additional packet headers that increase overhead and decrease space available for the payload or user data. Without knowledge of the virtual network infrastructure, instances attempt to send packets using the default Ethernet maximum transmission unit (MTU) of 1500 bytes. Internet protocol (IP) networks contain the path MTU discovery (PMTUD) mechanism to detect end-to-end MTU and adjust packet size accordingly. However, some operating systems and networks block or otherwise lack support for PMTUD causing performance degradation or connectivity failure.

    Ideally, you can prevent these problems by enabling jumbo frames on the physical network that contains your tenant virtual networks. Jumbo frames support MTUs up to approximately 9000 bytes which negates the impact of VXLAN overhead on virtual networks. However, many network devices lack support for jumbo frames and OpenStack administrators often lack control over network infrastructure. Given the latter complications, you can also prevent MTU problems by reducing the instance MTU to account for VXLAN overhead. Determining the proper MTU value often takes experimentation, but 1450 bytes works in most environments. You can configure the DHCP server that assigns IP addresses to your instances to also adjust the MTU.

    Note

    Some cloud images ignore the DHCP MTU option in which case you should configure it using metadata, a script, or other suitable method.

    • In the [DEFAULT] section, enable the dnsmasq configuration file:

      [DEFAULT]
      ...
      dnsmasq_config_file = /etc/neutron/dnsmasq-neutron.conf
      
    • Create and edit the /etc/neutron/dnsmasq-neutron.conf file to enable the DHCP MTU option (26) and configure it to 1450 bytes:

      dhcp-option-force=26,1450
      

Return to Networking controller node configuration.

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