X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=FAQ;h=dfe8242e0ab729f75f1895f9a1ec73d1f713fd5d;hb=5ca1ba484bd9ade5116a49cf241cb98219d7d696;hp=a98739cb36fc6fd387f9d602a378b82ea98887d5;hpb=af1ac4b91a1435e7280bec73bc3fd511075d093c;p=sliver-openvswitch.git diff --git a/FAQ b/FAQ index a98739cb3..dfe8242e0 100644 --- a/FAQ +++ b/FAQ @@ -128,21 +128,38 @@ A: All official releases have been through a comprehensive testing supplanted by the next major release. The current LTS release is 1.4.x. +Q: What Linux kernel versions does each Open vSwitch release work with? + +A: The following table lists the Linux kernel versions against which the + given versions of the Open vSwitch kernel module will successfully + build. The Linux kernel versions are upstream kernel versions, so + modified Linux kernels modified from the upstream sources may not + build in some cases even if they are based on a supported version. + This is most notably true of Red Hat Enterprise Linux (RHEL) kernels, + which are extensively modified from upstream. + + Open vSwitch Linux kernel + ------------ ------------- + 1.4.x 2.6.18 to 3.2 + 1.5.x 2.6.18 to 3.2 + 1.6.x 2.6.18 to 3.2 + 1.7.x 2.6.18 to 3.3 + 1.8.x 2.6.18 to 3.4 + 1.9.x 2.6.18 to 3.7 + + Open vSwitch userspace should also work with the Linux kernel module + built into Linux 3.3 and later. + + Open vSwitch userspace is not sensitive to the Linux kernel version. + It should build against almost any kernel, certainly against 2.6.18 + and later. + Q: What features are not available in the Open vSwitch kernel datapath that ships as part of the upstream Linux kernel? A: The kernel module in upstream Linux 3.3 and later does not include the following features: - - Bridge compatibility, that is, support for the ovs-brcompatd - daemon that (if you enable it) lets "brctl" and other Linux - bridge tools transparently work with Open vSwitch instead. - - We do not expect bridge compatibility to ever be available in - upstream Linux. If you need bridge compatibility, use the - kernel module from the Open vSwitch distribution instead of the - upstream Linux kernel module. - - Tunnel virtual ports, that is, interfaces with type "gre", "ipsec_gre", "capwap". It is possible to create tunnels in Linux and attach them to Open vSwitch as system devices. @@ -168,6 +185,21 @@ A: Tunnel and patch virtual ports are not supported, as described in the may not be transmitted. +Terminology +----------- + +Q: I thought Open vSwitch was a virtual Ethernet switch, but the + documentation keeps talking about bridges. What's a bridge? + +A: In networking, the terms "bridge" and "switch" are synonyms. Open + vSwitch implements an Ethernet switch, which means that it is also + an Ethernet bridge. + +Q: What's a VLAN? + +A: See the "VLAN" section below. + + Basic Configuration ------------------- @@ -414,6 +446,14 @@ Q: Is there any documentation on the database tables and fields? A: Yes. ovs-vswitchd.conf.db(5) is a comprehensive reference. +Q: When I run ovs-dpctl I no longer see the bridges I created. Instead, + I only see a datapath called "ovs-system". How can I see datapath + information about a particular bridge? + +A: In version 1.9.0, OVS switched to using a single datapath that is + shared by all bridges of that type. The "ovs-appctl dpif/*" + commands provide similar functionality that is scoped by the bridge. + VLANs ----- @@ -546,6 +586,25 @@ A: It's possible that you have the VLAN configured on your physical equally well. Refer to the documentation for the Port table in ovs-vswitchd.conf.db(5) for more information. +Q: I added a pair of VMs on different VLANs, like this: + + ovs-vsctl add-br br0 + ovs-vsctl add-port br0 eth0 + ovs-vsctl add-port br0 tap0 tag=9 + ovs-vsctl add-port br0 tap1 tag=10 + + but the VMs can't access each other, the external network, or the + Internet. + +A: It is to be expected that the VMs can't access each other. VLANs + are a means to partition a network. When you configured tap0 and + tap1 as access ports for different VLANs, you indicated that they + should be isolated from each other. + + As for the external network and the Internet, it seems likely that + the machines you are trying to access are not on VLAN 9 (or 10) and + that the Internet is not available on VLAN 9 (or 10). + Q: Can I configure an IP address on a VLAN? A: Yes. Use an "internal port" configured as an access port. For @@ -747,6 +806,27 @@ A: ovs-dpctl queries a kernel datapath, not an OpenFlow switch. It won't display the information that you want. You want to use "ovs-ofctl dump-flows" instead. +Q: It looks like each of the interfaces in my bonded port shows up + as an individual OpenFlow port. Is that right? + +A: Yes, Open vSwitch makes individual bond interfaces visible as + OpenFlow ports, rather than the bond as a whole. The interfaces + are treated together as a bond for only a few purposes: + + - Sending a packet to the OFPP_NORMAL port. (When an OpenFlow + controller is not configured, this happens implicitly to + every packet.) + + - The "autopath" Nicira extension action. However, "autopath" + is deprecated and scheduled for removal in February 2013. + + - Mirrors configured for output to a bonded port. + + It would make a lot of sense for Open vSwitch to present a bond as + a single OpenFlow port. If you want to contribute an + implementation of such a feature, please bring it up on the Open + vSwitch development mailing list at dev@openvswitch.org. + Contact -------