We are updating this material for Icehouse. You may find structure and/or content issues during this process. Configuring networking in OpenStack can be a bewildering experience. The following example shows the simplest production-ready configuration that is available: the legacy networking in OpenStack Compute, with a flat network, that takes care of DHCP. This set up uses multi-host functionality. Networking is configured to be highly available by distributing networking functionality across multiple hosts. As a result, no single network controller acts as a single point of failure. This process configures each compute node for networking. Install the appropriate packages for compute networking on the compute node only. These packages are not required on the controller node. So that the nova-network service can forward metadata requests on each compute node, each compute node must install the nova-api-metadata service, as follows: # apt-get install nova-network nova-api-metadata # yum install openstack-nova-network # zypper install openstack-nova-network Edit the nova.conf file to define the networking mode: # openstack-config --set /etc/nova/nova.conf DEFAULT \ network_manager nova.network.manager.FlatDHCPManager # openstack-config --set /etc/nova/nova.conf DEFAULT \ firewall_driver nova.virt.libvirt.firewall.IptablesFirewallDriver # openstack-config --set /etc/nova/nova.conf DEFAULT network_size 254 # openstack-config --set /etc/nova/nova.conf DEFAULT allow_same_net_traffic False # openstack-config --set /etc/nova/nova.conf DEFAULT multi_host True # openstack-config --set /etc/nova/nova.conf DEFAULT send_arp_for_ha True # openstack-config --set /etc/nova/nova.conf DEFAULT share_dhcp_address True # openstack-config --set /etc/nova/nova.conf DEFAULT force_dhcp_release True # openstack-config --set /etc/nova/nova.conf DEFAULT flat_interface eth1 # openstack-config --set /etc/nova/nova.conf DEFAULT flat_network_bridge br100 # openstack-config --set /etc/nova/nova.conf DEFAULT public_interface eth1 # openstack-config --set /etc/nova/nova.conf DEFAULT network_api_class nova.network.api.API # openstack-config --set /etc/nova/nova.conf DEFAULT security_group_api nova Edit the /etc/nova/nova.conf file and add these lines to the [DEFAULT] section: [DEFAULT] ... network_manager=nova.network.manager.FlatDHCPManager firewall_driver=nova.virt.libvirt.firewall.IptablesFirewallDriver network_size=254 allow_same_net_traffic=False multi_host=True send_arp_for_ha=True share_dhcp_address=True force_dhcp_release=True flat_network_bridge=br100 flat_interface=eth1 public_interface=eth1 Provide a local metadata service that is reachable from instances on this compute node. Perform this step only on compute nodes that do not run the nova-api service. # yum install openstack-nova-api # service openstack-nova-metadata-api start # chkconfig openstack-nova-metadata-api on Restart the network service: # service nova-network restart Start the network service and configure it to start when the system boots: # service openstack-nova-network start # chkconfig openstack-nova-network on Create a network that virtual machines can use. Do this once for the entire installation and not on each compute node. Run the nova network-create command on the controller: $ source openrc.sh $ nova network-create vmnet --fixed-range-v4=10.0.0.0/24 \ --bridge=br100 --multi-host=T