Understanding of Flat_interface and Public_interface

For the understanding of these two interface meanings twists, I will take note of the various understandings below. 2014-9-23#可以把flat_interface理解为Openstack整套生态系统内部的网络接口, the # of inter-node communication with each other can be understood by Public_interface as an administrator outside of the OpenStack system, interface for the control sideso in my notes flat_interface = Eth1 (ge NIC, mannual), Public_interface = Eth0 (BBG nic, static), because my default BBG is for management, GE is used for internal communication. 2014-10-28Review a post on GitHub ( https://github.com/ChaimaGhribi/Icehouse-Installation-Flat-Networking/blob/master/ Openstack-icehouse-installation-nova-network.rst#install-the-compute-service-nova), found in the text of the nova.conf public_interface=br100, it is very strange!I tried to make a GE netThe eth0 used for internal communication + Internet communication, BBG network eth1 for management. A floating IP address pool is created, and 3.242.164.4 is assigned to Cirros (internal IP 172.52.17.2), but the Cirros is not available to the outside world. So I will cancel the BBG network card gateway, with the GE NIC IP, netmask, Gateway. From my computer, 3.242.164.104 can ping or ssh to cirros. But I can't ping from the Cirros. I try to use the Public_interface = Br100 method in this article to achieve interoperability, but do not understand the principle . 2014-10-29Read an article today: HTTPS://GROUPS.GOOGLE.COM/FORUM/#!TOPIC/CHINA-OPENSTACK-USER-GROUP/7OBOGTCV6GK

q: Ask a question, I installed OpenStack (Havana) on a NIC on the host. Nova-network for network use. Configuration J follows Network_manager=nova.network.manager.flatdhcpmanager flat_network_bridge=br100 flat_interface= The eth0 Public_interface=eth0 eth0 network card address is 10.10.101.105, the gateway is 10.10.101.254 and can be connected to the extranet. The network segment for br100 and the IP of the virtual machine is 192.168.100.0/24. The problem now is that the virtual machine cannot access the extranet and the host's local area network. The ping command is as follows Ping www.baidu.comping www.baidu.com (115.239.210.27) from 192.168.100.1:icmp_seq=2 Redirect Host (new nexthop:10.10.101.254) From 192.168.100.1:icmp_seq=3redirect host (new nexthop:10.10.101.254) You can see that DNS should be OK, but you can't access the extranet.

A: Because of the recent busy other went, put this post forget, today occasionally see the mail, someone asked this question, I put my solution to say a bit. 1, if you have two network card, of course, will flat_interface and Flat_interface set to a different NIC is the best. Flat_interface is through the Network Bridge Connection virtual machine, arbitrarily set a network card on the line; Public_interface must be set to your Sisu network of the network card, so that the virtual machine can be directly connected to the Internet. 2, if you only have a network card such as "eth0", then the above settings do not have a problem, as to the network, is the iptables problem. My solution is to execute the following command. Iptables-t nat-a postrouting-o Br100-j Masquerade

This is the correct understanding so far, namely: flat, the public outside the main seems to be right, but the management network can also act as an inter-instance communication network (which is different from the 2014-9-23 understanding), so Flat_interface = Eth0 ( BBG). Public_interface=eth1 (GE), which uses the GE Network card to act as an instance to access the Internet.  2014-10-30  Yesterday's article said "Flat_interface casually set a network card on the line," Today think of the next seems reasonable, because the general situation, all compute nodes are connected to the network, and can certainly communicate with each other, so the flat network card can also be public network card.

Understanding of Flat_interface and Public_interface