[libvirt-users] [virtual interface] detach interface during boot succeed with no changes
by Yalan Zhang
Hi guys,
when I detach an interface from vm during boot (vm boot not finished), it
always fail. I'm not sure if there is an existing bug. I have
confirmed with someone that for disk, there is similar behavior, if
this is also acceptable?
# virsh destroy rhel7.2; virsh start rhel7.2 ;sleep 2; virsh
detach-interface rhel7.2 network 52:54:00:98:c4:a0; sleep 2; virsh
dumpxml rhel7.2 |grep /interface -B9
Domain rhel7.2 destroyed
Domain rhel7.2 started
Interface detached successfully
<address type='pci' domain='0x0000' bus='0x00' slot='0x06'
function='0x0'/>
</controller>
<interface type='network'>
<mac address='52:54:00:98:c4:a0'/>
<source network='default' bridge='virbr0'/>
<target dev='vnet0'/>
<model type='rtl8139'/>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x03'
function='0x0'/>
</interface>
When I detach after the vm boot, expand the sleep time to 10, it will succeed.
# virsh destroy rhel7.2; virsh start rhel7.2 ;sleep 10; virsh
detach-interface rhel7.2 network 52:54:00:98:c4:a0; sleep 2; virsh
dumpxml rhel7.2 |grep /interface -B9
Domain rhel7.2 destroyed
Domain rhel7.2 started
Interface detached successfully
-------
Best Regards,
Yalan Zhang
IRC: yalzhang
Internal phone: 8389413
2 years, 3 months
Set hostname of guest during installation time
by john doe
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
4 years, 1 month
guest-fsfreeze-freeze freezes all mounted block devices
by Marc Roos
I wondered if anyone here can confirm that
virsh qemu-agent-command domain '{"execute":"guest-fsfreeze-freeze"}'
Freezes all mounted block devices filesystems. So if I use 4 block
devices they are all frozen for snapshotting. Or just the root fs?
4 years, 4 months
[libvirt-users] Question about disabling UFO on guest
by Bao Nguyen
Hello everyone,
I would like to ask a question regarding to disable UFO of virtio vNIC in
my guest. I have read the document at https://libvirt.org/formatdomain.html
*host*
The csum, gso, tso4, tso6, ecn and ufo attributes with possible
values on and off can be used to turn off host offloading options. By
default, the supported offloads are enabled by QEMU. *Since 1.2.9 (QEMU
only)* The mrg_rxbuf attribute can be used to control mergeable rx buffers
on the host side. Possible values are on (default) and off. *Since 1.2.13
(QEMU only)*
*guest*
The csum, tso4, tso6, ecn and ufo attributes with possible
values on and off can be used to turn off guest offloading options. By
default, the supported offloads are enabl
ed by QEMU.
*Since 1.2.9 (QEMU only)*
Then I disabled UFO on my vNIC on guest as the following configuration
<devices>
<interface type='network'>
<source network='default'/>
<target dev='vnet1'/>
<model type='virtio'/>
<driver name='vhost' txmode='iothread' ioeventfd='on' event_idx='off'
queues='5' rx_queue_size='256' tx_queue_size='256'>
*<host gso='off' ufo='off' />*
*<guest ufo='off'/>*
</driver>
</interface>
</devices>
Then I reboot my node to get the change effect and it works. However, can I
disable the UFO without touching the host OS? or it always has to disable
on both host and guest like that?
Thanks,
Brs,
Natsu
4 years, 4 months
Could you please help with questions about the net failover feature
by Yalan Zhang
Hi laine,
I have leave some questions on IRC, but my VPN broken time after time.
Please ignore the questions on IRC.
In my understanding, the standby and primary hostdev interface may be in
different subnet.
I'm not sure whether it is correct. Could you please help to explain? Thank
you in advance.
For example, primary hostdev is connected to vf-pool with <pf='eth0'/>,
while the standby is connected to NAT network with " forward dev='eth0'".
The standby interface will get ip as 192.168.122.x, but after NAT, it will
be in the same subnet of the vf.
So after the VF is unplugged, the packet will still broadcast in the same
subnet, and the vm will get the packet as the standby share the same mac.
Right?
Thank you!
-------
Best Regards,
Yalan Zhang
IRC: yalzhang
4 years, 5 months
image of OS X how to boot
by Jerry Geis
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
4 years, 5 months
Do we need "amd_iommu=on" for AMD system anymore?
by Yalan Zhang
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/k...
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
4 years, 5 months
