====================================== Using DevStack with neutron Networking ====================================== This guide will walk you through using OpenStack neutron with the ML2 plugin and the Open vSwitch mechanism driver. .. _single-interface-ovs: Using Neutron with a Single Interface ===================================== In some instances, like on a developer laptop, there is only one network interface that is available. In this scenario, the physical interface is added to the Open vSwitch bridge, and the IP address of the laptop is migrated onto the bridge interface. That way, the physical interface can be used to transmit self service project network traffic, the OpenStack API traffic, and management traffic. .. warning:: When using a single interface networking setup, there will be a temporary network outage as your IP address is moved from the physical NIC of your machine, to the OVS bridge. If you are SSH'd into the machine from another computer, there is a risk of being disconnected from your ssh session (due to arp cache invalidation), which would stop the stack.sh or leave it in an unfinished state. In these cases, start stack.sh inside its own screen session so it can continue to run. Physical Network Setup ---------------------- In most cases where DevStack is being deployed with a single interface, there is a hardware router that is being used for external connectivity and DHCP. The developer machine is connected to this network and is on a shared subnet with other machines. The `local.conf` exhibited here assumes that 1500 is a reasonable MTU to use on that network. .. image:: /assets/images/neutron-network-1.png :alt: Network configuration for a single DevStack node DevStack Configuration ---------------------- The following is a complete `local.conf` for the host named `devstack-1`. It will run all the API and services, as well as serving as a hypervisor for guest instances. :: [[local|localrc]] HOST_IP=172.18.161.6 SERVICE_HOST=172.18.161.6 MYSQL_HOST=172.18.161.6 RABBIT_HOST=172.18.161.6 GLANCE_HOSTPORT=172.18.161.6:9292 ADMIN_PASSWORD=secret DATABASE_PASSWORD=secret RABBIT_PASSWORD=secret SERVICE_PASSWORD=secret ## Neutron options Q_USE_SECGROUP=True FLOATING_RANGE="172.18.161.0/24" IPV4_ADDRS_SAFE_TO_USE="10.0.0.0/22" Q_FLOATING_ALLOCATION_POOL=start=172.18.161.250,end=172.18.161.254 PUBLIC_NETWORK_GATEWAY="172.18.161.1" PUBLIC_INTERFACE=eth0 # Open vSwitch provider networking configuration Q_USE_PROVIDERNET_FOR_PUBLIC=True OVS_PHYSICAL_BRIDGE=br-ex PUBLIC_BRIDGE=br-ex OVS_BRIDGE_MAPPINGS=public:br-ex Adding Additional Compute Nodes ------------------------------- Let's suppose that after installing DevStack on the first host, you also want to do multinode testing and networking. Physical Network Setup ~~~~~~~~~~~~~~~~~~~~~~ .. image:: /assets/images/neutron-network-2.png :alt: Network configuration for multiple DevStack nodes After DevStack installs and configures Neutron, traffic from guest VMs flows out of `devstack-2` (the compute node) and is encapsulated in a VXLAN tunnel back to `devstack-1` (the control node) where the L3 agent is running. :: stack@devstack-2:~/devstack$ sudo ovs-vsctl show 8992d965-0ba0-42fd-90e9-20ecc528bc29 Bridge br-int fail_mode: secure Port br-int Interface br-int type: internal Port patch-tun Interface patch-tun type: patch options: {peer=patch-int} Bridge br-tun fail_mode: secure Port "vxlan-c0a801f6" Interface "vxlan-c0a801f6" type: vxlan options: {df_default="true", in_key=flow, local_ip="172.18.161.7", out_key=flow, remote_ip="172.18.161.6"} Port patch-int Interface patch-int type: patch options: {peer=patch-tun} Port br-tun Interface br-tun type: internal ovs_version: "2.0.2" Open vSwitch on the control node, where the L3 agent runs, is configured to de-encapsulate traffic from compute nodes, then forward it over the `br-ex` bridge, where `eth0` is attached. :: stack@devstack-1:~/devstack$ sudo ovs-vsctl show 422adeea-48d1-4a1f-98b1-8e7239077964 Bridge br-tun fail_mode: secure Port br-tun Interface br-tun type: internal Port patch-int Interface patch-int type: patch options: {peer=patch-tun} Port "vxlan-c0a801d8" Interface "vxlan-c0a801d8" type: vxlan options: {df_default="true", in_key=flow, local_ip="172.18.161.6", out_key=flow, remote_ip="172.18.161.7"} Bridge br-ex Port phy-br-ex Interface phy-br-ex type: patch options: {peer=int-br-ex} Port "eth0" Interface "eth0" Port br-ex Interface br-ex type: internal Bridge br-int fail_mode: secure Port "tapce66332d-ea" tag: 1 Interface "tapce66332d-ea" type: internal Port "qg-65e5a4b9-15" tag: 2 Interface "qg-65e5a4b9-15" type: internal Port "qr-33e5e471-88" tag: 1 Interface "qr-33e5e471-88" type: internal Port "qr-acbe9951-70" tag: 1 Interface "qr-acbe9951-70" type: internal Port br-int Interface br-int type: internal Port patch-tun Interface patch-tun type: patch options: {peer=patch-int} Port int-br-ex Interface int-br-ex type: patch options: {peer=phy-br-ex} ovs_version: "2.0.2" `br-int` is a bridge that the Open vSwitch mechanism driver creates, which is used as the "integration bridge" where ports are created, and plugged into the virtual switching fabric. `br-ex` is an OVS bridge that is used to connect physical ports (like `eth0`), so that floating IP traffic for project networks can be received from the physical network infrastructure (and the internet), and routed to self service project network ports. `br-tun` is a tunnel bridge that is used to connect OpenStack nodes (like `devstack-2`) together. This bridge is used so that project network traffic, using the VXLAN tunneling protocol, flows between each compute node where project instances run. DevStack Compute Configuration ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The host `devstack-2` has a very minimal `local.conf`. :: [[local|localrc]] HOST_IP=172.18.161.7 SERVICE_HOST=172.18.161.6 MYSQL_HOST=172.18.161.6 RABBIT_HOST=172.18.161.6 GLANCE_HOSTPORT=172.18.161.6:9292 ADMIN_PASSWORD=secret MYSQL_PASSWORD=secret RABBIT_PASSWORD=secret SERVICE_PASSWORD=secret ## Neutron options PUBLIC_INTERFACE=eth0 ENABLED_SERVICES=n-cpu,rabbit,q-agt,placement-client Network traffic from `eth0` on the compute nodes is then NAT'd by the controller node that runs Neutron's `neutron-l3-agent` and provides L3 connectivity. Neutron Networking with Open vSwitch and Provider Networks ========================================================== In some instances, it is desirable to use neutron's provider networking extension, so that networks that are configured on an external router can be utilized by neutron, and instances created via Nova can attach to the network managed by the external router. For example, in some lab environments, a hardware router has been pre-configured by another party, and an OpenStack developer has been given a VLAN tag and IP address range, so that instances created via DevStack will use the external router for L3 connectivity, as opposed to the neutron L3 service. Physical Network Setup ---------------------- .. image:: /assets/images/neutron-network-3.png :alt: Network configuration for provider networks On a compute node, the first interface, eth0 is used for the OpenStack management (API, message bus, etc) as well as for ssh for an administrator to access the machine. :: stack@compute:~$ ifconfig eth0 eth0 Link encap:Ethernet HWaddr bc:16:65:20:af:fc inet addr:10.0.0.3 eth1 is manually configured at boot to not have an IP address. Consult your operating system documentation for the appropriate technique. For Ubuntu, the contents of `/etc/network/interfaces` contains: :: auto eth1 iface eth1 inet manual up ifconfig $IFACE 0.0.0.0 up down ifconfig $IFACE 0.0.0.0 down The second physical interface, eth1 is added to a bridge (in this case named br-ex), which is used to forward network traffic from guest VMs. :: stack@compute:~$ sudo ovs-vsctl add-br br-ex stack@compute:~$ sudo ovs-vsctl add-port br-ex eth1 stack@compute:~$ sudo ovs-vsctl show 9a25c837-32ab-45f6-b9f2-1dd888abcf0f Bridge br-ex Port br-ex Interface br-ex type: internal Port phy-br-ex Interface phy-br-ex type: patch options: {peer=int-br-ex} Port "eth1" Interface "eth1" Service Configuration --------------------- **Control Node** In this example, the control node will run the majority of the OpenStack API and management services (keystone, glance, nova, neutron) **Compute Nodes** In this example, the nodes that will host guest instances will run the ``neutron-openvswitch-agent`` for network connectivity, as well as the compute service ``nova-compute``. DevStack Configuration ---------------------- .. _ovs-provider-network-controller: The following is a snippet of the DevStack configuration on the controller node. :: HOST_IP=10.0.0.2 SERVICE_HOST=10.0.0.2 MYSQL_HOST=10.0.0.2 RABBIT_HOST=10.0.0.2 GLANCE_HOSTPORT=10.0.0.2:9292 PUBLIC_INTERFACE=eth1 ADMIN_PASSWORD=secret MYSQL_PASSWORD=secret RABBIT_PASSWORD=secret SERVICE_PASSWORD=secret ## Neutron options Q_USE_SECGROUP=True ENABLE_TENANT_VLANS=True TENANT_VLAN_RANGE=3001:4000 PHYSICAL_NETWORK=default OVS_PHYSICAL_BRIDGE=br-ex Q_USE_PROVIDER_NETWORKING=True disable_service q-l3 ## Neutron Networking options used to create Neutron Subnets IPV4_ADDRS_SAFE_TO_USE="203.0.113.0/24" NETWORK_GATEWAY=203.0.113.1 PROVIDER_SUBNET_NAME="provider_net" PROVIDER_NETWORK_TYPE="vlan" SEGMENTATION_ID=2010 USE_SUBNETPOOL=False In this configuration we are defining IPV4_ADDRS_SAFE_TO_USE to be a publicly routed IPv4 subnet. In this specific instance we are using the special TEST-NET-3 subnet defined in `RFC 5737 `_, which is used for documentation. In your DevStack setup, IPV4_ADDRS_SAFE_TO_USE would be a public IP address range that you or your organization has allocated to you, so that you could access your instances from the public internet. The following is the DevStack configuration on compute node 1. :: HOST_IP=10.0.0.3 SERVICE_HOST=10.0.0.2 MYSQL_HOST=10.0.0.2 RABBIT_HOST=10.0.0.2 GLANCE_HOSTPORT=10.0.0.2:9292 ADMIN_PASSWORD=secret MYSQL_PASSWORD=secret RABBIT_PASSWORD=secret SERVICE_PASSWORD=secret # Services that a compute node runs ENABLED_SERVICES=n-cpu,rabbit,q-agt ## Open vSwitch provider networking options PHYSICAL_NETWORK=default OVS_PHYSICAL_BRIDGE=br-ex PUBLIC_INTERFACE=eth1 Q_USE_PROVIDER_NETWORKING=True Compute node 2's configuration will be exactly the same, except ``HOST_IP`` will be ``10.0.0.4`` When DevStack is configured to use provider networking (via ``Q_USE_PROVIDER_NETWORKING`` is True) - DevStack will automatically add the network interface defined in ``PUBLIC_INTERFACE`` to the ``OVS_PHYSICAL_BRIDGE`` For example, with the above configuration, a bridge is created, named ``br-ex`` which is managed by Open vSwitch, and the second interface on the compute node, ``eth1`` is attached to the bridge, to forward traffic sent by guest VMs. Miscellaneous Tips ================== Non-Standard MTU on the Physical Network ---------------------------------------- Neutron by default uses a MTU of 1500 bytes, which is the standard MTU for Ethernet. A different MTU can be specified by adding the following to the Neutron section of `local.conf`. For example, if you have network equipment that supports jumbo frames, you could set the MTU to 9000 bytes by adding the following :: [[post-config|/$Q_PLUGIN_CONF_FILE]] global_physnet_mtu = 9000 Disabling Next Generation Firewall Tools ---------------------------------------- DevStack does not properly operate with modern firewall tools. Specifically it will appear as if the guest VM can access the external network via ICMP, but UDP and TCP packets will not be delivered to the guest VM. The root cause of the issue is that both ufw (Uncomplicated Firewall) and firewalld (Fedora's firewall manager) apply firewall rules to all interfaces in the system, rather then per-device. One solution to this problem is to revert to iptables functionality. To get a functional firewall configuration for Fedora do the following: :: sudo service iptables save sudo systemctl disable firewalld sudo systemctl enable iptables sudo systemctl stop firewalld sudo systemctl start iptables To get a functional firewall configuration for distributions containing ufw, disable ufw. Note ufw is generally not enabled by default in Ubuntu. To disable ufw if it was enabled, do the following: :: sudo service iptables save sudo ufw disable Configuring Extension Drivers for the ML2 Plugin ------------------------------------------------ Extension drivers for the ML2 plugin are set with the variable ``Q_ML2_PLUGIN_EXT_DRIVERS``, and includes the 'port_security' extension by default. If you want to remove all the extension drivers (even 'port_security'), set ``Q_ML2_PLUGIN_EXT_DRIVERS`` to blank. Using Linux Bridge instead of Open vSwitch ------------------------------------------ The configuration for using the Linux Bridge ML2 driver is fairly straight forward. The Linux Bridge configuration for DevStack is similar to the :ref:`Open vSwitch based single interface ` setup, with small modifications for the interface mappings. :: [[local|localrc]] HOST_IP=172.18.161.6 SERVICE_HOST=172.18.161.6 MYSQL_HOST=172.18.161.6 RABBIT_HOST=172.18.161.6 GLANCE_HOSTPORT=172.18.161.6:9292 ADMIN_PASSWORD=secret DATABASE_PASSWORD=secret RABBIT_PASSWORD=secret SERVICE_PASSWORD=secret ## Neutron options Q_USE_SECGROUP=True FLOATING_RANGE="172.18.161.0/24" IPV4_ADDRS_SAFE_TO_USE="10.0.0.0/24" Q_FLOATING_ALLOCATION_POOL=start=172.18.161.250,end=172.18.161.254 PUBLIC_NETWORK_GATEWAY="172.18.161.1" PUBLIC_INTERFACE=eth0 Q_USE_PROVIDERNET_FOR_PUBLIC=True # Linuxbridge Settings Q_AGENT=linuxbridge LB_PHYSICAL_INTERFACE=eth0 PUBLIC_PHYSICAL_NETWORK=default LB_INTERFACE_MAPPINGS=default:eth0 Using MacVTap instead of Open vSwitch ------------------------------------------ Security groups are not supported by the MacVTap agent. Due to that, devstack configures the NoopFirewall driver on the compute node. MacVTap agent does not support l3, dhcp and metadata agent. Due to that you can chose between the following deployment scenarios: Single node with provider networks using config drive and external l3, dhcp ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This scenario applies, if l3 and dhcp services are provided externally, or if you do not require them. :: [[local|localrc]] HOST_IP=10.0.0.2 SERVICE_HOST=10.0.0.2 MYSQL_HOST=10.0.0.2 RABBIT_HOST=10.0.0.2 ADMIN_PASSWORD=secret MYSQL_PASSWORD=secret RABBIT_PASSWORD=secret SERVICE_PASSWORD=secret Q_ML2_PLUGIN_MECHANISM_DRIVERS=macvtap Q_USE_PROVIDER_NETWORKING=True enable_plugin neutron https://opendev.org/openstack/neutron ## MacVTap agent options Q_AGENT=macvtap PHYSICAL_NETWORK=default IPV4_ADDRS_SAFE_TO_USE="203.0.113.0/24" NETWORK_GATEWAY=203.0.113.1 PROVIDER_SUBNET_NAME="provider_net" PROVIDER_NETWORK_TYPE="vlan" SEGMENTATION_ID=2010 USE_SUBNETPOOL=False [[post-config|/$Q_PLUGIN_CONF_FILE]] [macvtap] physical_interface_mappings = $PHYSICAL_NETWORK:eth1 [[post-config|$NOVA_CONF]] force_config_drive = True Multi node with MacVTap compute node ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This scenario applies, if you require OpenStack provided l3, dhcp or metadata services. Those are hosted on a separate controller and network node, running some other l2 agent technology (in this example Open vSwitch). This node needs to be configured for VLAN tenant networks. For OVS, a similar configuration like described in the :ref:`OVS Provider Network ` section can be used. Just add the following line to this local.conf, which also loads the MacVTap mechanism driver: :: [[local|localrc]] ... Q_ML2_PLUGIN_MECHANISM_DRIVERS=openvswitch,linuxbridge,macvtap ... For the MacVTap compute node, use this local.conf: :: HOST_IP=10.0.0.3 SERVICE_HOST=10.0.0.2 MYSQL_HOST=10.0.0.2 RABBIT_HOST=10.0.0.2 ADMIN_PASSWORD=secret MYSQL_PASSWORD=secret RABBIT_PASSWORD=secret SERVICE_PASSWORD=secret # Services that a compute node runs disable_all_services enable_plugin neutron https://opendev.org/openstack/neutron ENABLED_SERVICES+=n-cpu,q-agt ## MacVTap agent options Q_AGENT=macvtap PHYSICAL_NETWORK=default [[post-config|/$Q_PLUGIN_CONF_FILE]] [macvtap] physical_interface_mappings = $PHYSICAL_NETWORK:eth1