Running Host Management on Open vSwitch

萨尔法保护

　　Open vSwitch (OVS)  brings lots of functionality to Linux virtualization hosts, including  the ability to use Link Aggregation Control Protocol (LACP) for enhanced  network interface card (NIC) failover and redundancy. In this post, I’m  going to show you how to run a host management interface on a LACP  bundle through OVS. This prevents you from having to give up a physical  interface for host management, and allows you to run all traffic through  OVS.
　　First, configure the LACP bundle as I describe in my post on link aggregation and LACP with OVS. You’ll want to ensure that the LACP configuration is working properly before you continue. Remember that you can use ovs-appctl bond/show  and ovs-appctl lacp/show  to help troubleshoot the LACP configuration and operation.
　　Next, create an “internal” interface that Linux will use as a Layer 3 interface. We’ll do this using ovs-vsctl, like this:
　　

　　
ovs-vsctl add-port ovsbr1 mgmt0 -- set interface mgmt0 type=internal
　　

　　This command adds a port called mgmt0 to the specified bridge (ovsbr1 in this example), and then sets the interface associated with mgmt0  to the type “internal.” I don’t yet know why setting the type to  internal is required, only that it’s necessary if you want the interface  to be usable by Linux as a Layer 3 interface.
　　If you need the management traffic on a specific VLAN, then modify  the command to specify a particular OVS fake bridge (more here on using fake bridges with VLANs):
　　

　　
ovs-vsctl add-port vlan100br mgmt0 -- set interface mgmt0 type=internal
　　


　　You can also just assign the VLAN tag directly,>　　

　　
ovs-vsctl set port mgmt0 tag=100
　　

　　Once the interface is created, then configure Linux to use that  interface as a Layer 3 interface with an IP address assigned. On Ubuntu  12.04 LTS, that means adding a stanza to the /etc/network/interfaces configuration file, like this:
　　

　　
auto mgmt0
　　
iface mgmt0 inet static
　　
address 192.168.254.100
　　
netmask 255.255.255.0
　　
gateway 192.168.254.254
　　
dns-nameservers 192.168.254.101
　　

　　And that’s it! You can now use the IP address assigned to the mgmt0  interface (or whatever you named it) to manage the Linux virtualization  host, all while knowing that you have a bonded LACP configuration  protecting you against a network link failure. I’m using this  configuration on all my Ubuntu-KVM hosts in my home lab; the physical  interfaces are members of LACP bonds.
　　(Oh, one side note: on Ubuntu, this configuration causes a delay  during the boot process. I don’t yet know why this delay occurs, or how  to fix it. I’ll post something if I figure it out.)
　　If you have any questions or thoughts about this configuration,  please feel free to speak up in the comments below—all courteous  comments are welcome.