Hot answers tagged

57

If you don't want to do any configuration inside the guest, then the only option is a DHCP server that hands out static IP addresses. If you use bridge mode, that will probably be some external DHCP server. Consult its manual to find out how to serve static leases. But at least in forward modes nat or route, you could use libvirt's built-in dnsmasqd (More ...


32

I'd like to start with a note that you should avoid using virsh attach-disk with its limited amount of options. Instead, I'd suggest to specify the exact disk format you prefer in a separate, temporary XML file or by using the virt-manager GUI application (for the latter, skip the first step). Create a temporary file with a disk definition like this one ...


31

Before following the steps, be sure that you are running these commands as normal user and that your user belongs to the group libvirtd (on some systems libvirt). Here are the following commands which I used: Listing current pools: $ virsh pool-list Name State Autostart ------------------------------------------- default ...


14

Yes, it is possible: virsh # help define NAME define - define (but don't start) a domain from an XML file SYNOPSIS define <file> DESCRIPTION Define a domain. OPTIONS [--file] <string> file containing an XML domain description


13

virsh implemented domrename in release 1.2.19: Sep 02 2015. So the current best practice is just: virsh domrename oldname newname As you might expect, thedomain must be stopped, but also it cannot have any snapshots.


13

virsh net-update is a good command for you (you don't need to restart/destroy your network etc) see: https://www.redhat.com/archives/libvir-list/2012-September/msg01380.html


12

You created your guest with virsh create (or its equivalent). This creates transient domains, which are deleted when they power off. To create persistent domains, use virsh define instead. These remain defined after they are powered off or destroyed, and can be started again at any time.


11

The Problem I've got the same problem and I haven't found a good solution. Here's what I found: The problem is that after resume, the system and hardware clock times on the guest are different: root@guest:~# date; hwclock Sat Oct 11 13:09:38 UTC 2014 Sat Oct 11 13:10:42 2014 -0.454380 seconds On the host, they agree: root@four:~# date; hwclock Sat Oct ...


11

If you get the response: virsh autostart domainname "cannot set autostart for transient domain" then virsh shutdown domainname virsh define xmlfile virsh start domainname virsh autostart domainname In my experience on Ubuntu 12.04, this only happens if a virsh undefine has been run. Domains created with virsh create usually allow ...


11

list files in /etc/libvirt/qemu/networks/ and /etc/libvirt/qemu/networks/autostart/ if empty - create it useful commands: virsh net-start default or virsh net-autostart default and virsh net-destroy default virsh net-undefine default service libvirtd restart for detailed explanation read wiki: http://wiki.libvirt.org/page/Networking


11

Changes made to a network take place the next time the network is started. You need to perform this series of operations. virsh net-edit somenet virsh net-destroy somenet virsh net-start somenet For confirmation of this, see functionality of virsh net-edit Note that restarting a network like this will terminate network connectivity for any VMs using this ...


11

This is not a distro problem, but a bug in Windows: http://keyliner.blogspot.se/2009/11/windows-7-slow-keyboard-response.html (second clause) That is what helped me: Start, Run, regedit Find this key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\i8042prt\Parameters On the detail side, right-click the blank area and add a new "DWORD (32-bit)" ...


11

You can't use switch port security on the Cisco since all the VMs will be sharing a physical switch port. And you can't use Linux iptables because the traffic is being bridged, not routed, through the hypervisor machine. But you can emulate switch port security on the hypervisor with Linux ebtables, which is a lesser-known layer 2/3 firewall on the Linux ...


10

This feature was requested a long time ago. Now libvirt supports it by providing two new commands: domifaddr and net-dhcp-leases Usage: domifaddr <domain> [interface] [--full] [--source lease|agent] Example outputs: virsh # domifaddr f20 --source agent Name MAC address Protocol Address ------------------------------------------...


10

Working example of using Debian jessie as host and guest operating system. create a VM using virt-install or virt-manager In any case you will get serial console statements added to VM.xml file in guest VM run the following systemctl enable serial-getty@ttyS0.service systemctl start serial-getty@ttyS0.service in guest VM in /etc/default/grub replace ...


10

You can use a virtual tablet instead of the virtual mouse, and then you won't have to press Ctrl_L & Alt_L. The virtual tablet also improves the mouse tracking by using absolute coordinates instead of relative motion deltas. To use the virtual tablet, first shutdown your vm. Using virt-manager, select the virtual machine, then select View -> Details, ...


9

If you don't have the xml for the running vm (eg. after transient migration), you can do virsh dumpxml vm_name > vm_name.xml virsh define vm_name.xml To check: virsh list --all --persistent The VM should now be listed. Or virsh dominfo vm_name There should be a line with 'Persistent: yes'.


9

I will give very rough idea/explanation. In OP situation, besides measuring within the VM, the host should be look at too. In this case, we can assume the following are correct In all the test, the host I/O(disk) bandwidth is not max out. As VM("monitoring") I/O increases with more CPUs allocated to it. If host I/O was already max out, there should be no ...


9

Red Hat is making a huge containerization push. They're building an entire new product, Red Hat Enterprise Linux Atomic Host, around it. For a less radical approach, take a look at their RHEL7 beta Resource Management and Linux Containers Guide; you'll notice it pushes libvirt-lxc and makes no mention of the lxc tools.


9

Kids, don't try this at home: Libvirt should have rejected the creation of a domain with a space in its name, so someone did something strange to create the domain to begin with. To recover from this is going to require some hand-editing of files you aren't normally supposed to touch manually. So this is what I would do: Stop libvirtd (your VMs will ...


8

The best bet for upgrading servers is to use live migration. Have a spare host which is given a fully upgraded software stack, then live migrate all running VMs to that host. Now you can safely upgrade & reboot the original host. This is how most public clouds handle their host upgrades without introducing downtime to their customer VMs. Of course the ...


7

This seems to me like a permission issue on the host: By default, the qemu/kvm process is started as a non-privileged user (libvirt-qemu in Debian Wheezy). So only files accessible (or writable) by that user are accessible (writable) by the VM guests. You might try setting ownership of the directory to the user qemu is run as (see user= and group= in /etc/...


7

The added net-update command in virsh should allow an dhcp-host update without restarting the virtual network (I have not tested it yet). man virsh: net-update network command section xml [--parent-index index] [[--live] [--config] | [--current]] Update the given section of an existing network definition, with the changes optionally taking effect ...


7

You have to go to QEMU Monitor and run: change vnc display,options Where display is <host>:<display_number> or unix:<path> or none. Options are options for display. See: https://qemu.weilnetz.de/doc/qemu-doc.html#sec_005finvocation E.g. To change the port to 5905 and accept VNC connections for any host: change vnc :5 If you are using ...


7

Deleting a file does not actually delete the file, it reduces the number of names pointing to an inode. If both the number of names and the number of open file descriptors to the file reach 0, the data gets deleted. So if you delete a file that's still open by some application, that application can still happily use that file. Only when the last file ...


7

What's the conventional wisdom regarding LXC and RHEL-like systems today? Personally, I find the current setup somewhat lacking. LXC seems more at the forefront -- certainly more maintained. How are you implementing them? In terms of offering it as a virtualization option I am not. I find the current technological setup lacking. No username namespace....


7

You're seeing this error because Ubuntu put their own customizations into its version of libvirt and qemu/KVM. RHEL, of course, did the same thing. But there's always a machine type that will work, namely, pc. This is always aliased to the latest i440fx machine type available on the hypervisor at the time the VM is defined. Somewhere in the XML you'll find ...


7

You should edit the part of the xml definition of your guest so that it contains a subset of CPU capabilities that are found in both CPUs (Intel and AMD). You can use virsh to find this subset. Here's how: At the 1st host $ virsh capabilities | virsh cpu-baseline /dev/stdin > /tmp/host1.xml # copy this file to Host#2 -- e.g.: $ scp /tmp/host1.xml $...


6

VMware Workstation 7 doesn't support nested hvm. You should try VMware Workstation 8 or 9. Edit the virtual machine and modify the processor options. In the Virtualization engine , check "Virtualize Intel-x/EPT or AMD-V/RVI"。 If you are using VMware Workstation 8, you should also modify the .vmx file of the vm, add a new line : vhv.enable = "TRUE" You can ...


Only top voted, non community-wiki answers of a minimum length are eligible