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[libvirt-users] Mounting directory as readonly within LXC
by Harish Vishwanath 21 Apr '15

21 Apr '15

Hello Is there a way to mount a directory as readonly when using LXC with libvirt? Something like: <filesystem type="mount"> <source dir="/sw/py27/python2.7_x86_64"/> <target dir="/opt//py27"/> <readonly/> </filesystem> The documentation says readonly only works with KVM/QEMU. Regards, Harish

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[libvirt-users] QEMU interface type=ethernet
by Brian Rak 21 Apr '15

21 Apr '15

With Libvirt under modern kernels, you can't use <interface type='ethernet'> unless QEMU is running as root. Running qemu as root is not ideal, but I was able to track down the issue to this linux change: http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=c… Which means that if you're seeing errors like this: 2015-03-02T18:00:51.243477Z qemu-kvm: -netdev tap,script=/tmp/vnet380622.sh,id=hostnet1: could not open /dev/net/tun: Operation not permitted 2015-03-02T18:00:51.243518Z qemu-kvm: -netdev tap,script=/tmp/vnet380622.sh,id=hostnet1: Device 'tap' could not be initialized They can be resolved like this: 1) Edit /etc/libvirt/qemu.conf, and add "/dev/net/tun" to the cgroup_device_acl option 2) Run: setcap cap_net_admin+eip /bin/qemu-system-x86_64 This will give QEMU CAP_NET_ADMIN when it runs. Make sure you review `man capabilities` to see what capabilities this actually gets qemu. The downside here is that in the event a guest somehow breaks out of qemu, CAP_NET_ADMIN gives them a bunch of scary permissions that could result in you having a seriously bad day (it's enough permissions to MITM all the machine's traffic, which could easily result in compromise) It looks to me like libvirt already has the ability to create tap devices and pass them into qemu (src/util/virnetdevtap.c - virNetDevTapCreateInBridgePort), however you need to actually be using a bridged network to do this. There is no way to have libvirt just create a tap device and leave the rest to user defined scripts. I don't think I have the necessary knowledge to add that feature in a generic way, but it seems like it would be pretty handy. I'll probably just work around it by removing the virNetDevBridgeAddPort call from our version of libvirt.

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[libvirt-users] Libvirt disk API
by fu lirong 21 Apr '15

21 Apr '15

Hi all: I am studying Libvirt API , I am wondering the API about the disk manage is TBD(to be difine). The edition is libvirt 0.7.5 ,but the edition is too old ,The website is http://libvirt.org/guide/html/Application_Development_Guide-Introduction.ht… So, if I want to manage the VM disk , for example read the disk, what should I do ? Sincerely thanks a lot

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[libvirt-users] <qemu:commandline> domain XML tag is not working?
by Chengyuan Li 21 Apr '15

21 Apr '15

Hi, I tried to enable virtio-blk data plane feature for VMs in my openstack environment, the hypervisor is ubuntu 14.04, libvirt 1.2.2 and QEMU 2.0. As nova doesn't support that parameter yet, I did belows 1. nova boot a VM with raw disk image. 2. nova stop the VM. 3. run "virsh edit <instance-id>" on the hyprvisor node, and adding below into instance xml just before </domain>. However, the <qemu:commandline> part is ignored and not saved after closing virsh edit, seems that libvirt rejected these changes. Is there any XML syntax error here? Or libvirt doesn't support <qemu:commandline> tag? <qemu:commandline> <qemu:arg value='-set'/> <qemu:arg value='device.drive-virtio-disk0.x-data-plane=on'/> </qemu:commandline> Regards, Chengyuan.

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[libvirt-users] libvirt and guest processes
by dt sweval 21 Apr '15

21 Apr '15

Hi I wanted to find out if there is way to list all the running processes in a guest VM from the hypervisor. Like the output of 'ps -ef' from inside the guest VM, but without logging in or ssh into it. Thanks dtsweval

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[libvirt-users] inquiry about differences between the tap and the vnet in the virt-manager
by wh.h＠foxmail.com 20 Apr '15

20 Apr '15

inquiry about differences between the tap and the vnet in the virt-manager Greetings! I encounter a problem about the network when using virt-manager to create and run a VM. when I want to establish a network bridge for the guest OS, I generally use two kinds of ways described as fellow : First method : create a bridge with the help of linux commad: brctl, or Second method : using virt-manager (1) create a bridge with the help of linux commad: brctl I use a script to establish a bridge, there are many script examples on the web to establish a bridge. when I restart the network service, I get the bridge : 1.1 create network bridge [root@localhost ~]# ifconfig br0 Link encap:Ethernet HWaddr C2:CD:89:61:2C:F0 inet addr:192.168.1.189 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::c0cd:89ff:fe61:2cf0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:16 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:1080 (1.0 KiB) eth2 Link encap:Ethernet HWaddr 00:25:90:8E:C0:F0 inet addr:172.16.1.189 Bcast:172.16.255.255 Mask:255.255.0.0 inet6 addr: fe80::225:90ff:fe8e:c0f0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:918998 errors:0 dropped:0 overruns:0 frame:0 TX packets:2033 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:84486598 (80.5 MiB) TX bytes:148116 (144.6 KiB) Memory:fbe20000-fbe3ffff [root@localhost ~]# brctl show bridge name bridge id STP enabled interfaces br0 8000.0025908ec0f0 no virbr0 8000.525400b1de42 yes virbr0-nic 1.2 add bridge interface the eth2 device is a physical ethernet device, [root@localhost ~]# brctl addif br0 eth2 [root@localhost ~]# brctl show bridge name bridge id STP enabled interfaces br0 8000.0025908ec0f0 no eth2 virbr0 8000.525400b1de42 yes virbr0-nic 1.3 create tap and add it to the bridge create tap: tunctl -t tap0 -u root brctl addif br0 tap0 ifconfig tap0 up chmod a+rw /dev/net/tun echo 1 > /proc/sys/net/ipv4/ip_forward iptables -t nat -A POSTROUTING -j MASQUERADE add it to the bridge [root@localhost ~]# brctl addif br0 tap0 [root@localhost ~]# brctl show bridge name bridge id STP enabled interfaces br0 8000.0025908ec0f0 no eth2 tap0 virbr0 8000.525400b1de42 yes virbr0-nic [root@localhost kvm_img]# ifconfig br0 Link encap:Ethernet HWaddr 00:25:90:8E:C0:F0 inet addr:172.16.1.189 Bcast:172.16.255.255 Mask:255.255.0.0 inet6 addr: fe80::c0cd:89ff:fe61:2cf0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:37947 errors:0 dropped:0 overruns:0 frame:0 TX packets:10485 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:2581300 (2.4 MiB) TX bytes:40996927 (39.0 MiB) eth2 Link encap:Ethernet HWaddr 00:25:90:8E:C0:F0 inet6 addr: fe80::225:90ff:fe8e:c0f0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:957962 errors:0 dropped:34 overruns:0 frame:0 TX packets:38466 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:87721507 (83.6 MiB) TX bytes:42551007 (40.5 MiB) Memory:fbe20000-fbe3ffff tap0 Link encap:Ethernet HWaddr F2:55:FC:F8:95:DC inet6 addr: fe80::f055:fcff:fef8:95dc/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:11 errors:0 dropped:0 overruns:0 frame:0 TX packets:1328 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:846 (846.0 b) TX bytes:173159 (169.1 KiB) 1.4 boot the guest (using the tap0) kvm -boot c -localtime -m 4G -hda /home/kvm_img/centos6p4.img -net nic -net tap,ifname=tap0,script=no -enable-kvm (2) using virt-manager 2.1 create network bridge [root@localhost ~]# ifconfig br0 Link encap:Ethernet HWaddr C2:CD:89:61:2C:F0 inet addr:192.168.1.189 Bcast:192.168.1.255 Mask:255.255.255.0 inet6 addr: fe80::c0cd:89ff:fe61:2cf0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:16 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:0 (0.0 b) TX bytes:1080 (1.0 KiB) eth2 Link encap:Ethernet HWaddr 00:25:90:8E:C0:F0 inet addr:172.16.1.189 Bcast:172.16.255.255 Mask:255.255.0.0 inet6 addr: fe80::225:90ff:fe8e:c0f0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:918998 errors:0 dropped:0 overruns:0 frame:0 TX packets:2033 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:84486598 (80.5 MiB) TX bytes:148116 (144.6 KiB) Memory:fbe20000-fbe3ffff [root@localhost ~]# brctl show bridge name bridge id STP enabled interfaces br0 8000.0025908ec0f0 no virbr0 8000.525400b1de42 yes virbr0-nic 2.2 add bridge interface the eth2 device is a physical ethernet device, [root@localhost ~]# brctl addif br0 eth2 [root@localhost ~]# brctl show bridge name bridge id STP enabled interfaces br0 8000.0025908ec0f0 no eth2 virbr0 8000.525400b1de42 yes virbr0-nic 2.3 run the virt-manager and select the NIC option I find the bridge created above , configure it as fellow : in "Virtual Network Interface " setting: Source device: Host device tap0 (bridge br0) Device model: e1000 Mac address: 52:54:00:84:E3:62 2.4 I start the VM using virt-manager I get a vnet0 device created by virt-manager, [root@localhost ~]# ifconfig br0 Link encap:Ethernet HWaddr 00:25:90:8E:C0:F0 inet addr:172.16.1.189 Bcast:172.16.255.255 Mask:255.255.0.0 inet6 addr: fe80::c0cd:89ff:fe61:2cf0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:62160 errors:0 dropped:1 overruns:0 frame:0 TX packets:22071 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:4007196 (3.8 MiB) TX bytes:59626981 (56.8 MiB) eth2 Link encap:Ethernet HWaddr 00:25:90:8E:C0:F0 inet6 addr: fe80::225:90ff:fe8e:c0f0/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:982209 errors:0 dropped:47 overruns:0 frame:0 TX packets:61101 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:89496644 (85.3 MiB) TX bytes:61778801 (58.9 MiB) Memory:fbe20000-fbe3ffff vnet0 Link encap:Ethernet HWaddr FE:54:00:84:E3:62 inet6 addr: fe80::fc54:ff:fe84:e362/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:5 errors:0 dropped:0 overruns:0 frame:0 TX packets:114 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:500 RX bytes:670 (670.0 b) TX bytes:13720 (13.3 KiB) both of the methods above seems that the network of guest OS is OK at most of environments, and I can get the attributes of the virtual network device . They are seemed to be the same. about the tap0： [root@localhost ~]# ethtool -i tap0 driver: tun version: 1.6 firmware-version: bus-info: tap supports-statistics: no supports-test: no supports-eeprom-access: no supports-register-dump: no supports-priv-flags: no about the vnet0 created by virt-manager : [root@localhost ~]# ethtool -i vnet0 driver: tun version: 1.6 firmware-version: bus-info: tap supports-statistics: no supports-test: no supports-eeprom-access: no supports-register-dump: no supports-priv-flags: no but the action between tap and vnet is not exactly the same！I will describe it in the following. this is my project environment: hardware : intel xeon E5 2600 server from supermicro host OS: centos 6.4 (kernel version is changed to 3.15.10 by me) virtual software : KVM+qemu 2.1.3 guest OS: centos 6.4 (kernel is not changed : 2.6.32 64bit) when I establish the network by the first method: create a bridge with the help of Linux commad: brctl, tap0 device is created in the host and assigned to the guest OS. tap0 device gets a name “eth0” in the guest OS. I use “ping ” command to test network state . I get the following result : concept explanation : local host: the OS where the guest OS is running remote host: another server which is connected to the local host using ethernet network . and this is my results: ping local host from guest OS is OK, I get reply from local host; ping remote host from local host is OK, I get reply from remote host; ping remote host from guest OS is not OK, I don’t get any reply from remote host; and this is my question. when I establish the network by the second method: using virt-manager, at this time , vnet0 device is created in the host and assigned to the guest OS. vnet0 device gets a name “eth0” in the guest OS. I also use “ping ” command to test network state . I get the following result : ping local host from guest OS is OK, I get reply from local host; ping remote host from local host is OK, I get reply from remote host; ping remote host from guest OS is OK, I get reply from remote host; my question is : why I cannot get reply when I ping remote host from guest OS using the first method? I use the same bridge: br0, so I think that the bridge: br0 is not responsible for the fault. and I have also stop the firewall . I guess the reason is that there are some differences between the tap device created by linux command and vnet device created by virt-manager. could you please kindly give my some advices to solve the problem ? I would be grateful if you could give me some advice . look forward to your reply ! weihua wh.h(a)foxmail.com

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[libvirt-users] Question regarding management of VMs using libvirtd.
by somenathpal . 20 Apr '15

20 Apr '15

Hi All, I have a question regarding the uses of libvirtd. We have the following situation to manage. We have several hosts with libvirtd running. We have one management application to manage different VMs launched in those different hosts. We want to configure the system such a way so that one libvirtd can collect information about the VMs launched by other libvirtd running in different hosts. Is it possible? Could you please point me to some resource around this? In this we will be able to get information about VMs from single source and need not to query different host for VMs info. Regards, Somenath

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[libvirt-users] virsh shutdown <domain> not fully working on win7 ?
by Marko Weber | 8000 20 Apr '15

20 Apr '15

hello list, i have a running vm with win7. When i fire up an 'virsh shutdown win7' nothing happens. When i fire up a second the same command, then the win7 machine is shutting down. Why do i need to fire up this command twice? Any ideas? best regards marko --

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[libvirt-users] (no subject)
by Daniel Sanabria 19 Apr '15

19 Apr '15

Hi, After upgrading my systems to Fedora 21 I decided to give Firewalld and NetworkManager technologies a try instead of keep relying on iptables and network.service but I now have my doubts. I have a F21 host with br0 configured with a network-script file to obtain its IP via dhcp (no problems with this), firewalld is running on the host and the guests are using br0 and dhcp to obtain the IPs from the same source the host/br0 is getting its own IP. The problem I'm having is that, after some time, packets from the guests are not being forwarded by br0 but I can't quite locate the reason for this. It is not until I restart the guest that everything starts working again (restarting NetworkManager in the guest does not work). Why br0 stops forwarding packets? What would be the right approach to get this setup working? Should I just forget about Firewalld and NetworkManager by disable them and instead keep using iptables and network.service? Thanks in advance, Daniel

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[libvirt-users] virsh shutdown <domain> not fully working on win7 ?
by Marko Weber | 8000 17 Apr '15

17 Apr '15

hello list, i have a running vm with win7. When i fire up an 'virsh shutdown win7' nothing happens. When i fire up a second the same command, then the win7 machine is shutting down. Why do i need to fire up this command twice? Any ideas? best regards marko --

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