Hello It's working now. I've put the mac address in the xml definition. Thank you very much, Regards.
2011/2/10 Laine Stump <la...@laine.org> > On 02/10/2011 09:51 AM, Tanguy ROZIER wrote: > >> OK so he should fix the problem with libvirt to associate a fixed MAC >> to the interface of the VM : >> >> <interface type='bridge'> >> <source bridge='br0'/> >> <mac address="00:11:22:33:44:55"/> <----------this is here : >> you must *define* the MAC address of your interface >> </interface> >> > > As I said in my last mail, if you do not manually define a MAC address for > an interface, libvirt will automatically generate a random mac address, and > save it into the domain config for you, so that the 2nd and subsequent times > you start the guest, it will use the same mac address. So, there is no > requirement that you manually define the MAC address. > > For example, I just edited an existing domain config with "virsh edit > domainname" and added this: > > > <interface type='network'> > <source network='default'/> > <model type='virtio'/> > </interface> > > Then I immediately ran "virsh dumpxml domainname", and the interface config > had been magically transformed: > > <interface type='network'> > <mac address='52:54:00:e2:75:a4'/> > <source network='default'/> > <model type='virtio'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/> > </interface> > > This mac address (and pci addressing information) is stored in the > persistent config for the guest, so they will be the same every time the > guest is started. > > If this is not happening, it's due to 1 of 3 reasons: > > 1) You are using a *very* old libvirt. I'm fairly certain, that it has > auto-generated mac addresses at least since I became involved with libvirt 2 > years ago (and possibly it's always been that way). > > 2) The guests are being "virsh create"ed as transient guests, so that the > auto-generated mac address is never saved. "virsh create" is the wrong tool > for this job, a combination of "virsh define" followed by "virsh start" > would be more appropriate. > > 3) there is a bug somewhere. > > > 2011/2/10 Laine Stump<la...@laine.org>: >> >>> On 02/10/2011 08:50 AM, Tanguy ROZIER wrote: >>> >>>> Your problem is related to udev : every reboot of VM, udev in VM >>>> checks the MAC address of the ethernet interface of the system to >>>> associate it with a static name (eth0, eth1...). >>>> If you change the MAC address of the Ethernet interface of your VM, it >>>> will detect a new interface and associate it with a new name (ethx+1). >>>> In order to avoid it : >>>> try not to change the MAC address of your VM ethernet device (you can >>>> fix it with libvirt xml), >>>> >>> When a domain is defined with an interface, if no mac address is >>> supplied, >>> libvirt will automatically generate one and write that generated mac back >>> to >>> the config, so that the next time the guest boots it will be presented >>> with >>> an ethernet having the same mac address as the previous time. >>> >>> How are you defining your guests? Are you perhaps using "virsh create" >>> (but >>> using an existing image file) to create a transient guest each time you >>> want >>> to boot the guest, rather than doing "virsh define" once to create a >>> persistent guest, then using "virsh start" each time you want to boot it? >>> You should be doing the latter - if you continuously use "virsh create", >>> libvirt will think that it's a "throw away" guest, and won't save the >>> config >>> (or any changes to it), so the next time you do "virsh create", the disk >>> image will have memory of the previous run (by having "eth0" assigned to >>> some particular mac address), but libvirt won't have any memory of it (it >>> thinks you're creating a brand new guest), so it will generate a new mac >>> address for the interface, the guest will boot, see a "new" interface, >>> notice that "eth0" is already taken, so it will use "eth1", and so on. >>> >>> If you actually are using "virsh define" to define a persistent guest, do >>> a >>> "virsh dumpxml" of the guest after you've started and destroyed it, and >>> see >>> if there is a mac address in the interface config. If not, that's a bug. >>> >>> >>> or deactivate this mecanism in the VM : search in >>>> /etc/udev/rules.d/70-persistent-net.rules : it calls >>>> /lib/udev/write_net_rules at every reboot, you could chmod -x this >>>> script in order to avoid it. >>>> >>> This may work (or may not - I haven't investigated), but it isn't the >>> right >>> way to fix this problem. It's dealing with the symptom rather than the >>> cause. >>> >>> >>> Tanguy >>>> >>>> 2011/2/10 Marcela Castro León<mcast...@gmail.com>: >>>> >>>>> Hello Laine: >>>>> I've revised the configuration and followed all your instructions. >>>>> I'll try to give you a better explain of my problem. >>>>> >>>>> a) I need a bridged (3) configuration, because I have to connect the >>>>> guests >>>>> from each others. (via ssh and execute mpi). I've three hosts, each of >>>>> one >>>>> has at least a guest. >>>>> I'll only explain about the configuration of one of them, because the >>>>> problem is only related a one configuration. >>>>> hostname=rionegro ip=192.168.1.4 >>>>> guest-name=rnompi1 >>>>> >>>>> b) I've configured host bridge following step by step ther instruction >>>>> on >>>>> http://wiki.libvirt.org/page/Networking >>>>> this is the /etc/network/config >>>>> >>>>> # The loopback network interface >>>>> auto lo >>>>> iface lo inet loopback >>>>> >>>>> >>>>> auto br0 >>>>> iface br0 inet static >>>>> address 192.168.1.4 >>>>> netmask 255.255.255.0 >>>>> network 192.168.1.0 >>>>> broadcast 192.168.1.255 >>>>> gateway 192.168.1.10 >>>>> bridge_ports eth0 >>>>> bridge_stp on >>>>> bridge_fd 0 >>>>> bridge_maxwait 0 >>>>> >>>>> c) this is the xml guest configuration related to the network. >>>>> >>>>> <interface type='bridge'> >>>>> <source bridge='br0'/> >>>>> </interface> >>>>> >>>>> >>>>> d) But the guest doesn't get any IP automatically, and create an >>>>> interface >>>>> with a variable name (eth4, eth5,etch6..). I don't know how to achieve >>>>> the >>>>> guest don't behave like this and create always its network interface >>>>> with >>>>> a >>>>> fixed name, for example, eth0). >>>>> >>>>> Why I ask that? >>>>> >>>>> if the guest created an interface with a fixed name, I would configure >>>>> and >>>>> static ip for the it. >>>>> I'm attaching a printscreen "rnompi1.jpg" that show what ifconfig ahow >>>>> on >>>>> the guest (eth14 and without any IP). It doesn't get their host either. >>>>> >>>>> The only way I achieve to solve but "temporally" until reboot is >>>>> configuring >>>>> the guest statically using the name of the interface that has just >>>>> up.In >>>>> that case every works fine, and the guest can connect to all the other >>>>> guests on the lan and others can connect to it. >>>>> But this only works until reboot or reconfigure the guest, because each >>>>> time >>>>> the name of interface change, and my configuration I had done of >>>>> /etc/network/interface didn't work any more because is related to >>>>> another >>>>> interface. >>>>> >>>>> I hope I've explained better the problem I have. >>>>> >>>>> Thank you very much, you've already helped too much to better >>>>> understand >>>>> the >>>>> different cases of network configuration >>>>> >>>>> Regards. >>>>> >>>>> >>>>> >>>>> >>>>> 2011/2/10 Marcela Castro León<mcast...@gmail.com> >>>>> >>>>>> Hello Laine: >>>>>> Thank you very much. >>>>>> I've showed only one of the guest, each one have it's own ip address. >>>>>> Anyway, I'll follow your advise of revise all the configuration after >>>>>> reading the doc. >>>>>> Thank you very much again. >>>>>> Regards. >>>>>> >>>>>> 2011/2/8 Laine Stump<la...@laine.org> >>>>>> >>>>>>> (For future questions such as this, you may find you get a better >>>>>>> response (and lower signal-noise ratio) by asking on the recently >>>>>>> -created >>>>>>> libvirt-users@redhat.com list, as libvir-list has a very large >>>>>>> volume >>>>>>> of >>>>>>> patches and discussion about the internals of libvirt) >>>>>>> >>>>>>> On 02/08/2011 12:05 PM, Marcela Castro León wrote: >>>>>>> >>>>>>> Hello >>>>>>> I've a lan of virtual machine configured with bridge. I've a private >>>>>>> lan >>>>>>> of 4 machine, but one of them have 2 lan-card with access to >>>>>>> internet. >>>>>>> >>>>>>> Evertything works almost fine, except that I've configured on each >>>>>>> guest >>>>>>> the static configuration of the bridge with the ip address, like >>>>>>> this: >>>>>>> >>>>>>> auto lo >>>>>>> iface lo inet loopback >>>>>>> >>>>>>> auto eth6 >>>>>>> iface eth6 inet static >>>>>>> address 192.168.1.41 >>>>>>> network 192.168.1.0 >>>>>>> netmask 255.255.255.0 >>>>>>> gateway 192.168.1.10 >>>>>>> >>>>>>> >>>>>>> So are you saying that you're attempting to give each guest the >>>>>>> *same* >>>>>>> IP >>>>>>> address? There's no way that can possibly work, even if each is >>>>>>> connected to >>>>>>> a separate virtual network or bridge. Since the host's IP stack can >>>>>>> "see" >>>>>>> all of the guests' network traffic, regardless of the connection mode >>>>>>> you >>>>>>> choose, each must have a unique IP address even if they can't see >>>>>>> each >>>>>>> other. >>>>>>> >>>>>>> >>>>>>> >>>>>>> But each time I, for example, define the guest, it start with a >>>>>>> ascending >>>>>>> number of interface: eth6,eth7, eth8, etc, Now is initializing with >>>>>>> eth12. >>>>>>> >>>>>>> There must be a mixup in the explanation - I'm understanding that you >>>>>>> put >>>>>>> the same config file in each guest, but each guest, when it starts, >>>>>>> shows a >>>>>>> different ethernet interface in its ifconfig. That doesn't seem >>>>>>> right, >>>>>>> because none of the guests know about each other. Or are you saying >>>>>>> something different? Where are you seeing the "eth6", "eth7", ... >>>>>>> "eth12"? >>>>>>> In the guest XML config maybe? >>>>>>> >>>>>>> So, it doesn't get the manual configuration I've done on the >>>>>>> /etc/network/interfaces. >>>>>>> How can avoid this way of work of the number of ethernet interface >>>>>>> the >>>>>>> guest start? >>>>>>> >>>>>>> Why are you doing a manual/static definition on the guest at all? >>>>>>> It's >>>>>>> simpler to just leave the guest to automatically configure its eth0, >>>>>>> and if >>>>>>> you really want a particular IP address for a particular guest, >>>>>>> handle >>>>>>> that >>>>>>> with a<host> element in the<dhcp> section of the virtual >>>>>>> network the >>>>>>> guest >>>>>>> is connected to (or, if you're using a pure bridging setup, then in >>>>>>> the >>>>>>> static hosts config of the dhcp server on that network). >>>>>>> >>>>>>> >>>>>>> A way i'm trying to solve is configuring the interface trough the >>>>>>> guest >>>>>>> xml definition, >>>>>>> >>>>>>> The guest xml interface configuration cannot be used to setup the IP >>>>>>> address, route, etc config of the guest. It is only used for two >>>>>>> things: >>>>>>> >>>>>>> 1) configuring what kind of hardware appears on the guest (but not >>>>>>> what >>>>>>> name the guest gives to it!) >>>>>>> >>>>>>> 2) configuring how that hardware is connected to the physical network >>>>>>> (usually either via an existing bridge interface on the host (in >>>>>>> order >>>>>>> for >>>>>>> the guest to appear as if its directly connected to the physical >>>>>>> network), >>>>>>> or via a "virtual network" created by libvirt (which is really just a >>>>>>> bridge >>>>>>> that's not directly connected to any physical interface, relying >>>>>>> instead on >>>>>>> the host's IP stack to route packets from the guest out to the >>>>>>> physical >>>>>>> network.) >>>>>>> >>>>>>> but the operation "define" on virsh accepted without error the xml >>>>>>> i've >>>>>>> done, but the dumpxml doesn't show them, so, it doesn't work at all. >>>>>>> I've followed the instruction that said the manual "Application >>>>>>> development guide - a guide to application development with libvirt" >>>>>>> on >>>>>>> page >>>>>>> 71. >>>>>>> >>>>>>> >>>>>>> That document is targeted towards software developers writing >>>>>>> applications to manage virtual guests using the libvirt API, not for >>>>>>> system >>>>>>> administrators who are configuring virtual guests manually (or, more >>>>>>> likely, >>>>>>> by using software that uses the libvirt API, eg virsh or >>>>>>> virt-manager). >>>>>>> It >>>>>>> likely contains more detail and less overview than what you need, >>>>>>> which >>>>>>> is >>>>>>> probably what led to the confusion. I've included a pointer to a wiki >>>>>>> page >>>>>>> below that is more the appropriate level of information (Justin, if >>>>>>> the >>>>>>> docs >>>>>>> you were working on are somewhere easily accessible, you can point to >>>>>>> those >>>>>>> instead.) >>>>>>> >>>>>>> >>>>>>> The whole definition of the VM is attached, but the related to >>>>>>> interface >>>>>>> is: >>>>>>> <interface type='bridge'> >>>>>>> <source bridge='br0'/> >>>>>>> <target dev='vnet0'/> >>>>>>> <protocol> >>>>>>> <ip address="192.168.1.41" prefix="24"/> >>>>>>> <route gateway="192.168.1.10"/> >>>>>>> </protocol> >>>>>>> <bridge stp="off" delay="0.01"> >>>>>>> <interface type="ethernet" name="eth12"> >>>>>>> <protocol> >>>>>>> <ip address="192.168.1.41" prefix="24"/> >>>>>>> <route gateway="192.168.1.10"/> >>>>>>> </protocol> >>>>>>> </interface> >>>>>>> </bridge> >>>>>>> </interface> >>>>>>> >>>>>>> >>>>>>> You are confusing the guest interface config (that is part of the >>>>>>> guest's >>>>>>> XML config, and described above), and host physical interface config >>>>>>> (that >>>>>>> is not in any way associated with guest config, but instead used to >>>>>>> configure the host's physical network interfaces, bridges, bonds, and >>>>>>> vlan >>>>>>> interfaces; and nearly as important, is not supported on Ubuntu >>>>>>> anyway). >>>>>>> >>>>>>> Actual guest interface config is *much* simpler than that. >>>>>>> >>>>>>> >>>>>>> >>>>>>> But after define, the dumpxml only show this part: >>>>>>> <interface type='bridge'> >>>>>>> <mac address='52:54:00:3c:92:9a'/> >>>>>>> <source bridge='br0'/> >>>>>>> </interface> >>>>>>> >>>>>>> >>>>>>> That's because everything else you've put in your guest config is not >>>>>>> actually a part of a valid guest interface config, and so is ignored. >>>>>>> >>>>>>> >>>>>>> >>>>>>> I would appreciate any help to solve the question. The problem I've >>>>>>> is >>>>>>> I >>>>>>> lost the access to the guest every time the libvirt change the name >>>>>>> of >>>>>>> the >>>>>>> interface eth1,2,3, etc. >>>>>>> >>>>>>> In this case I think it may be useful to start over. You've somehow >>>>>>> been >>>>>>> tricked into misunderstanding the way that network configuration in >>>>>>> libvirt >>>>>>> works, confusing host interface config with guest interface config, >>>>>>> and >>>>>>> the >>>>>>> resulting config bears little resemblance to what would actually >>>>>>> work. >>>>>>> >>>>>>> == >>>>>>> The first step is to read this page: >>>>>>> >>>>>>> http://wiki.libvirt.org/page/Networking >>>>>>> >>>>>>> to get a basic overview. >>>>>>> >>>>>>> == >>>>>>> Second step: you should decide which of the three methods of >>>>>>> connecting >>>>>>> to guests to the physical network you want to use: >>>>>>> >>>>>>> 1) NATed >>>>>>> 2) routed >>>>>>> 3) bridged >>>>>>> >>>>>>> The simplest is (1), and that will probably work just fine as long as >>>>>>> 1) >>>>>>> you don't need incoming connections to the guests, and 2) you're not >>>>>>> concerned about getting the last fraction of an ounce of performance >>>>>>> out of >>>>>>> the network. >>>>>>> >>>>>>> Depending on which of those 3 you decide to use: >>>>>>> >>>>>>> == >>>>>>> Third step: follow the instructions to either create a bridge >>>>>>> interface >>>>>>> on the host connected to a physical network interface (for (3)), or >>>>>>> to >>>>>>> create a libvirt virtual network using one of the two modes ((1) or >>>>>>> (2) >>>>>>> - >>>>>>> actually the stock libvirt config already has a "default" network >>>>>>> that >>>>>>> is >>>>>>> probably adequate for (1), and unless you understand IP routing very >>>>>>> well, >>>>>>> you'll likely want to avoid (2)). >>>>>>> >>>>>>> Once the physical network is setup: >>>>>>> >>>>>>> == >>>>>>> Fourth step: define your guests. In each guest, you'll have an >>>>>>> <interface> element, but it will be much simpler than what you've >>>>>>> previously >>>>>>> tried. For bridged mode, the interface section would look like this: >>>>>>> >>>>>>> <interface type='bridge'> >>>>>>> <source bridge='br0'/> >>>>>>> </interface> >>>>>>> >>>>>>> Depending on the guest, you may want to specify what type of hardware >>>>>>> is >>>>>>> presented to the guest (default is rtl, which almost always works, >>>>>>> but >>>>>>> is >>>>>>> not the best perfrorming), in particular, if the guest supports >>>>>>> virtio-net, >>>>>>> you'll want to add this into the<interface> element: >>>>>>> >>>>>>> <model type='virtio'/> >>>>>>> >>>>>>> For NATed or routed mode, the guest's interface definition would look >>>>>>> like this: >>>>>>> >>>>>>> <interface type='network'> >>>>>>> <source network='default'/> >>>>>>> </interface> >>>>>>> >>>>>>> (replace "default" with the name of the network you've defined, if >>>>>>> you've >>>>>>> defined your own). In this case also, you can add a<model >>>>>>> type='...'/> >>>>>>> if >>>>>>> appropriate. >>>>>>> >>>>>>> Note that I don't put anything in the<interface> element about MAC >>>>>>> address, target device, or bus address. Those are all setup >>>>>>> automatically by >>>>>>> libvirt the first time you start the guest, and it will make sure >>>>>>> that >>>>>>> the >>>>>>> guests don't interfere with each other. >>>>>>> >>>>>>> == >>>>>>> Fifth step: only if you need a particular guest to have a particular >>>>>>> fixed IP address, either 1) edit the network config file on the >>>>>>> guest, >>>>>>> 2) >>>>>>> add a static host to the libvirt virtual network definition (giving >>>>>>> the >>>>>>> MAC >>>>>>> address provided to the guest by libvirt during the initial guest >>>>>>> startup) >>>>>>> with a<host> element added to the<dhcp> element of the network; >>>>>>> details >>>>>>> are here: >>>>>>> >>>>>>> http://www.libvirt.org/formatnetwork.html >>>>>>> >>>>>>> or 3) if you're using the bridged method to connect to the physical >>>>>>> network, again either configure the guest's own config file, or add a >>>>>>> static >>>>>>> host definition to the dhcp server running on your physical network. >>>>>>> >>>>>>> If you still have problems don't hesitate to send another mail >>>>>>> (although, >>>>>>> as I said at the top, sending to libvirt-users@redhat.com may yield >>>>>>> better >>>>>>> results than libvir-l...@redhat.com). >>>>>>> >>>>>> _______________________________________________ >>>>> libvirt-users mailing list >>>>> libvirt-users@redhat.com >>>>> https://www.redhat.com/mailman/listinfo/libvirt-users >>>>> >>>>> >>>> >>> >> >> >
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