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qemu guest agent(QGA) in guest OS
by Henry lol 02 Dec '20

02 Dec '20

Hello, AFAIK, QGA is automatically installed and run in guest OS after installing OS from iso file whereas it's not installed in case of installing OS on the host even with same iso and configuration. So, I am wondering how it works differently depending on the guest or host. Does the OS installer selectively install packages? thanks.

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How to exit console in L2 vm?
by Yalan Zhang 01 Dec '20

01 Dec '20

Hi, I have a question about nested virtualization. The scenario is as below: 1. Prepare the nested environment, start L2 guest. 2. On the host, connect the L1 vm console, then on L1 guest, connect the L2 guest console: (host)# virsh console L1_vm Connected to domain L1_vm Escape character is ^] (Ctrl + ]) ... (L1 vm)# virsh console L2_vm Connected to domain L2_vm Escape character is ^] (Ctrl + ]) ... (L2 vm)# <=== press " ^] " to exit the console, it return to the **host** (host)# Is it expected that "^]" in L2 guest will exit thoroughly to the host, not the L1 guest? Thank you! ------- Best Regards, Yalan Zhang IRC: yalzhang

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qemu no-shutdown behavior in libvirt
by Luna Xu Yamada 01 Dec '20

01 Dec '20

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Debugging virtiofs
by Popog 27 Nov '20

27 Nov '20

I can't seem to start a VM with virtiofs. Everything is running as root (unraid) with a pretty simple setup: <filesystem type='mount' accessmode='passthrough'> <driver type='virtiofs'/> <binary path='/usr/libexec/virtiofsd' /> <source dir='/mnt/user/shared'/> <target dir='shared_mount'/> </filesystem> Even with debug logging at max, all I get in the main log is: qemu-system-x86_64: -device vhost-user-fs-pci,chardev=chr-vu-fs0,tag=shared_mount,bus=pci.5,addr=0x0: Failed to write msg. Wrote -1 instead of 12. qemu-system-x86_64: -device vhost-user-fs-pci,chardev=chr-vu-fs0,tag=shared_mount,bus=pci.5,addr=0x0: vhost_dev_init failed: Operation not permitted shutting down, reason=failed And in the fsd log: [ID: 00029648] virtio_session_mount: Waiting for vhost-user socket connection... [ID: 00029648] virtio_session_mount: Received vhost-user socket connection [ID: 00000001] pivot_root(., .): Invalid argument Nothing else in any other logs (e.g. dmesg). What do these errors mean? How do I troubleshoot this?

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image works in native but not in vm when cpu mode='host-passthrough' is set
by daggs 25 Nov '20

25 Nov '20

Greetings. I have an image I've created with a bunch of chost flags which works on my machine when it comes to native boot. if I take that same image into a vm managed via libvirt, I get kernel panic. I'd assume that something is missing from my vm config, question is what and what I can do about it? here is the flags part of lscpu in native and vm: https://dpaste.com/3TR8QJ5G8 and the vm's xml: https://dpaste.com/984JX4LUQ if I build the image with the default flags (march=x86-64), the vm boots well. my new chost is -O2 -pipe -march=skylake -mabm -mno-adx -mno-avx -mno-avx2 -mno-bmi -mno-bmi2 -mno-f16c -mno-fma -mno-xsave -mno-xsavec -mno-xsaveopt -mno-xsaves -mno-sgx the cpu is Intel(R) Pentium(R) CPU G4560 @ 3.50GHz thoughts? Thanks, Dagg.

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Openshift Kubevirt lab?
by Luis Gonzalez 18 Nov '20

18 Nov '20

Is there an RHPDS lab for Kubevirt? -- Luis Gonzalez Consultant, Container Infrastructure Red Hat <https://www.redhat.com/> lgonzal(a)redhat.com M: 404.784.7166 IM: luisgonzalez GPG: 2800156E8386EA133D4F10AC3381C1457F69FF84 <https://www.redhat.com/>

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DNS forwarding for guest domains on isolated network
by Jörg Kastning 12 Nov '20

12 Nov '20

Hi @all, I'm having trouble to realize my use case and hope somebody could help me. # Use case For a home lab I want to deploy several guest domains. These domains must not have a direct or NAT connection to the internet or my LAN. They should only be able to reach my LAN and the internet through a proxy. # What I've done I've created the following virtual switch in isolated mode: $ sudo virsh net-dumpxml private1 <network connections='3'> <name>private1</name> <uuid>THE-UUID</uuid> <bridge name='virbr1' stp='on' delay='0'/> <mac address='DE:AD:BE:EF:FF:FF'/> <domain name='private1'/> <ip address='192.168.100.1' netmask='255.255.255.0'> <dhcp> <range start='192.168.100.128' end='192.168.100.254'/> </dhcp> </ip> </network> I've setup a guest domain that serves as a proxy and several other guests. # My issue Nameresolution for *.private1 works fine on this network. But I'm not able to resolve domains from the outside world like github.com. I understood that libvirt is forwarding dns resolution requests to the hosts nameserver configured in /etc/resolv.conf in case the dnsmasq instance for the virtual network is not able to resolve the name. My guess, in my setup this don't work, because the virtual switch is in isolated mode, right? # My questions * What can I do to achieve my use case described above? * Is it possible to use the isolated mode here or do I have to use a different mode? It's important that the guest domains could only connect to the internet by using the proxy. Regards, Joerg

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Upgrade CentOS 7 to 8, error: network is already in use by interface
by Filip Hruska 08 Nov '20

08 Nov '20

Hi, I've been trying to migrate some of my CentOS 7 KVM hypervisors to CentOS 8, and I have encountered the following issue while trying to load my network config: virsh: error: Failed to start network test1 error: internal error: Network is already in use by interface virbr2 journalctl: error : networkCheckRouteCollision:123 : internal error: Network is already in use by interface virbr2 I use the following network definitions, which are a bit non-standard, however they work perfectly on CentOS 7: <network> <name>test1</name> <forward mode='open'/> <bridge name='virbr1' stp='off' delay='0'/> <mac address='52:54:00:c1:a7:7c'/> <dns enable='no'/> <ip address='10.0.0.1' netmask='255.255.255.255'></ip> <route address='192.168.1.22' prefix='32' gateway='10.0.0.1'/> </network> <network> <name>test2</name> <forward mode='open'/> <bridge name='virbr2' stp='off' delay='0'/> <mac address='52:54:00:54:09:3c'/> <dns enable='no'/> <ip address='10.0.0.1' netmask='255.255.255.255'></ip> <route address='192.168.1.33' prefix='32' gateway='10.0.0.1'/> </network> My question is, why is the behaviour different across CentOS releases, despite the libvirt versions apparently matching? Output from both systems is the same: # virsh version Compiled against library: libvirt 4.5.0 Using library: libvirt 4.5.0 Using API: QEMU 4.5.0 Running hypervisor: QEMU 2.12.0 What would be the best approach on patching out this check, so I can continue using my network config? Just to summarize the expected output: - virbr1 and virbr2 get created, each one with an address 10.0.0.1/32. - Two routes get created: 192.168.1.22 via 10.0.0.1 dev virbr1 192.168.1.33 via 10.0.0.1 dev virbr2 Thanks, Filip Hruska

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consume existing tap device when libvirt / qemu run as different users
by Miguel Duarte de Mora Barroso 07 Nov '20

07 Nov '20

Hello, I'm having some doubts about consuming an existing - already configured - tap device from libvirt (with `managed='no' ` attribute set). In KubeVirt, we want to have the consumer side of the tap device run without the NET_ADMIN capability, which requires the UID / GID of the tap creator / opener to match, as per the kernel code in [0]. As such, we create the tap device (with the qemu user / group on behalf of qemu), which will ultimately be the tap consumer. This leads me to question: why is libvirt opening / calling `ioctl(..., TUNSETIFF, ...) ` on the tap device when it already exists - [1] & [2] ? Why can't the tap device (already configured) be left alone, and let qemu consume it ? The above is problematic for KubeVirt, since our setup currently has libvirt running as root (while qemu runs as a different user), which is preventing us from removing NET_ADMIN (libvirt & qemu run as different users). Thanks in advance for your time, Miguel [0] - https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/dri… [1] - https://github.com/libvirt/libvirt/blob/99a1cfc43889c6d425a64013a12b234dde8… [2] - https://github.com/libvirt/libvirt/blob/v6.0.0/src/util/virnetdevtap.c#L274

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Set hostname of guest during installation time
by john doe 05 Nov '20

05 Nov '20

Hi, I would like to set the hostname when installing a guest, with the below command the hostname is not set to 'try06' in the guest: virt-install --name=try06 --graphic none --pxe --network bridge=virbr0 How can I set the hostname of the guest during installation time? I realy appriciate the support I'm getting in here, I'm fairly new to libvirt. -- John Doe

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