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image of OS X how to boot
by Jerry Geis 01 Jul '20

01 Jul '20

I have an image of OS X that I made with from the physical disk using dd. When I boot with libvirt-manager and environment I get an error. no bootable option or device was found. Using CentOS 8 host - I tried fdisk image.img and I no longer see any options there to toggle bootable partition option. How can I boot OSX ? Thanks, Jerry

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plug pre-created tap devices to libvirt guests
by Miguel Duarte de Mora Barroso 01 Jul '20

01 Jul '20

Hi all, I'm aware that it is possible to plug pre-created macvtap devices to libvirt guests - tracked in RFE [0]. My interpretation of the wording in [1] and [2] is that it is also possible to plug pre-created tap devices into libvirt guests - that would be a requirement to allow kubevirt to run with less capabilities in the pods that encapsulate the VMs. I took a look at the libvirt code ([3] & [4]), and, from my limited understanding, I got the impression that plugging existing interfaces via `managed='no' ` is only possible for macvtap interfaces. Would you be able to shed some light into this ? Is it possible on libvirt-5.6.0 to plug pre-created tap devices to libvirt guests ? [0] - https://bugzilla.redhat.com/show_bug.cgi?id=1723367 [1] - https://bugzilla.redhat.com/show_bug.cgi?id=1723367#c2 [2] - https://bugzilla.redhat.com/show_bug.cgi?id=1723367#c3 [3] - https://github.com/libvirt/libvirt/blob/master/src/qemu/qemu_interface.c#L4… [4] - https://github.com/libvirt/libvirt/blob/master/src/qemu/qemu_interface.c#L4…

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Do we need "amd_iommu=on" for AMD system anymore?
by Yalan Zhang 30 Jun '20

30 Jun '20

Hi, Since long time ago, to enable the SR-IOV VF pci passthrough function, I'm always adding "amd_iommu=on" into kernel cmdline on AMD system. But recently I found even I do not do this action, IOMMU is still enabled by kernel on AMD system. After searching, I found there is no such setting any more, refer to https://github.com/torvalds/linux/blob/master/Documentation/admin-guide/ker… There are only 3 possible value as below: amd_iommu= fullflush off force_isolation Could anyone can help to confirm the changes? Thank you! And another question, it is said that the "iommu=pt" option is to improves IO performance for devices in the host, it is not a must for VF PCI passthrough, right? I'm not sure about the user cases. [Reference] 1. Reference about adding "amd_iommu=on", and it may be outdated: http://dpdk-guide.gitlab.io/dpdk-guide/setup/iommu.html 2. On AMD system without adding "amd_iommu=on" in the kernel cmdline, the iommu is enabled: # cat /proc/cmdline BOOT_IMAGE=(hd0,msdos1)/vmlinuz-4.18.0-193.el8.x86_64 root=/dev/mapper/rhel_hp--dl385g10--16-root ro crashkernel=auto resume=/dev/mapper/rhel_hp--dl385g10--16-swap rd.lvm.lv=rhel_hp-dl385g10-16/root rd.lvm.lv=rhel_hp-dl385g10-16/swap console=ttyS0,115200n81 # dmesg | grep -i iommu [ 3.712029] iommu: Default domain type: Passthrough [ 6.736019] pci 0000:00:00.2: IOMMU performance counters supported ... [ 6.780040] pci 0000:e0:00.2: IOMMU performance counters supported [ 6.786740] pci 0000:00:01.0: Adding to iommu group 0 [ 6.791876] pci 0000:00:01.1: Adding to iommu group 1 [ 6.797015] pci 0000:00:01.2: Adding to iommu group 2 [ 6.802150] pci 0000:00:01.4: Adding to iommu group 3 ... [ 7.866463] pci 0000:e0:00.2: Found IOMMU cap 0x40 [ 7.920222] perf/amd_iommu: Detected AMD IOMMU #0 (2 banks, 4 counters/bank). [ 7.927428] perf/amd_iommu: Detected AMD IOMMU #1 (2 banks, 4 counters/bank) ... ------- Best Regards, Yalan Zhang IRC: yalzhang

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Virtual Bridge "Network" for Sandbox
by Paul O'Rorke 30 Jun '20

30 Jun '20

Hi all, I couldn't find any documentation on this, hopefully someone can point me in the right direction. I recently set up a sand-boxed environment for our developers. There are domain controller(s), workstations and servers in there. The whole thing is running on a single host using a "Virtual Network" defined in virt-manager on that host. Now I find I want to add more guests and there are not enough resources on this one host. Can I somehow make this Virtual Network available to two hosts? I do not want to move to a bridged network and have to physically join the two hosts with a discrete link when they are already on the same subnet at the host level. Is that possible? -- *Paul O'Rorke*

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get contents of a storage volume in bytes
by Shashwat shagun 29 Jun '20

29 Jun '20

Hi, i have two machines with libvirt installed. I want to move a storage volume from the 1st machine to 2nd machine with code. I'm thinking of reading a storage volume into a byte array/stream then uploading through my own/custom handler (written in go) to the 2nd machine's custom handler which will then be writing the byte stream to libvirt storage volume. Is there a libvirt function to read storage volume into byte stream? Shashwat. shashwatshagun2581(a)gmail.com

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RBD volume pools and locks
by Guy Godfroy 26 Jun '20

26 Jun '20

Hello, One of my libvirt cluster is using a RBD volume pool. I wish that I could configure libvirt lock manager to use RBD locks. Is that possible? I read here https://libvirt.org/kbase/locking.html that libvirt lock manager is shipped with 2 active plugins. Is there any other plugins that exist? Thanks. Guy Godfroy

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virsh edit does not work when <initiator> and <auth> is used in config
by Fourhundred Thecat 25 Jun '20

25 Jun '20

Hello, I am having problem when using: "virsh edit <vm_name>" my VM has network iscsi disk defined: <disk type='network' device='disk'> <driver name='qemu' type='raw'/> <source protocol='iscsi' name='iqn.1992-08.com.netapp:5481.60080e50001ff2000000000051aee24d/0'> <host name='10.1.212.52' port='3260'/> <initiator> <iqn name='iqn.2013-01.bla.bla:01:test'/> </initiator> <auth username='myname'> <secret type='iscsi' usage='libvirtiscsi'/> </auth> </source> ... </disk> when I defined thje VM the first time, as always, libvirt reorders the lines in the XML config file as it likes. One of the reordering it did, was to put the "<initiator>" block above the "<auth>" block. But once I want to edit, "virsh edit <vm_name>", whatever change I make, even unrelated to iscsi disk, it reports error: error: XML document failed to validate against schema: Unable to validate doc against /usr/share/libvirt/schemas/domain.rng Extra element devices in interleave Element domain failed to validate content after long trial and error, I found I can finally save it when I reorder the "<initiator>" and "<auth>" blocks, so that "<auth>" is above "<initiator>". Once i save it, libvirt then reorders it back to the order, which will generate erro next time I attemt to edit. Anyway, this seems like a bug, and especially evil one. How could I get rid of this behaviour? thanks,

2 1

volume pool for LXC
by Guy Godfroy 24 Jun '20

24 Jun '20

Hello, Is it possible to use volume pools for LXC ? For instance LVM pools. It seems to be supporte by LXC bare commands. From the man page of lxc-create : -B, --bdev backingstore 'backingstore' is one of 'dir', 'lvm', 'loop', 'btrfs', 'zfs', 'rbd', or 'best'. The default is 'dir', meaning that the container root filesystem will be a directory under /var/lib/lxc/container/rootfs. This backing store type allows the optional --dir ROOTFS to be specified, meaning that the container rootfs should be placed under the specified path, rather than the default. (The 'none' backingstore type is an alias for 'dir'.) If 'btrfs' is specified, then the target filesystem must be btrfs, and the container rootfs will be created as a new subvolume. This allows snapshotted clones to be created, but also causes rsync --one-filesystem to treat it as a separate filesystem. If backingstore is 'lvm', then an lvm block device will be used and the following further options are available: --lvname lvname1 will create an LV named lvname1 rather than the default, which is the container name. --vgname vgname1 will create the LV in volume group vgname1 rather than the default, lxc. --thinpool thinpool1 will create the LV as a thin-provisioned volume in the pool named thinpool1 rather than the default, lxc. --fstype FSTYPE will create an FSTYPE filesystem on the LV, rather than the default, which is ext4. --fssize SIZE will create a LV (and filesystem) of size SIZE rather than the default, which is 1G. If backingstore is 'loop', you can use --fstype FSTYPE and --fssize SIZE as 'lvm'. The default values for these options are the same as 'lvm'. If backingstore is 'rbd', then you will need to have a valid configuration in ceph.conf and a ceph.client.admin.keyring defined. You can specify the following options : --rbdname RBDNAME will create a blockdevice named RBDNAME rather than the default, which is the container name. --rbdpool POOL will create the blockdevice in the pool named POOL, rather than the default, which is 'lxc'. If backingstore is 'best', then lxc will try, in order, btrfs, zfs, lvm, and finally a directory backing store.

1 0

qemu hook: event for source host too
by Guy Godfroy 23 Jun '20

23 Jun '20

Hello, this is my first time posting on this mailing list. I wanted to suggest a addition to the qemu hook. I will explain it through my own use case. I use a shared LVM storage as a volume pool between my nodes. I use lvmlockd in sanlock mode to protect both LVM metadata corruption and concurrent volume mounting. When I run a VM on a node, I activate the desired LV with exclusive lock (lvchange -aey). When I stop the VM, I deactivate the LV, effectively releasing the exclusive lock (lvchange -an). When I migrate a VM (both live and offline), the LV has to be activated on both source and target nodes, so I have to use a shared lock (lvchange -asy). That's why I need a hook event on the source host too (as far as I know after my tests, the migration event is only triggered on the target host). Is such a feature a possibility? Thanks for your attention. Guy Godfroy

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Missing vnet interface in migration
by Ales Musil 22 Jun '20

22 Jun '20

Hi, in oVirt we have come across issue with a missing vnet interface (Original bug report [0]). This happened once in a huge batch of migrations e.g 2 failed out of 1200 and we came to conclusion that this is happening somewhere out of our control as libvirt reports: 2020-05-17 02:34:11,530+0000 ERROR (migsrc/623f6cc1) [virt.vm] (vmId='623f6cc1-d49f-43a4-8170-b5fec01f2897') operation failed: binding 'vnet54' is already being removed (migration:278) Unfortunately we don't have libvirt logs and producing them might not be possible. Is there anything else we can do to tackle down this issue? Thank you. Regards, Ales [0] https://bugzilla.redhat.com/1837395 -- Ales Musil Software Engineer - RHV Network Red Hat EMEA <https://www.redhat.com> amusil(a)redhat.com IM: amusil <https://red.ht/sig>

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