diffficult/installing_virt_manager.md

## installing_virt_manager.md

      
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              installing_virt_manager.md
            
          
    Easy instructions to get QEMU/KVM and virt-manager up and running on Arch


Make sure your cpu support kvm with below command:
 grep -E "(vmx|svm)" --color=always /proc/cpuinfo


Make sure BIOS have enable “Virtualization Technology”.


User access to /dev/kvm so add your account into kvm(78) group:
 sudo gpasswd -a $(whoami) kvm


Loading kernel modules kvm_intel or kvm_amd depend on your CPU, Add module name in /etc/modules-load.d/kvm.conf:
 kvm_intel


Load module:
modprobe kvm_amd


Install qemu, virt-manager, dnsmasq and iptables:
 sudo pacman -S --needed qemu virt-manager dnsmasq iptables-nft


Run and enable boot up start libvirtd daemon:
 systemctl enable --now libvirtd


Use PolicyKit authorization create /etc/polkit-1/rules.d/50-libvirt.rules (before /etc/polkit-1/rules.d/50-org.libvirt.unix.manage.rules) as below context:


/* Allow users in kvm group to manage the libvirt
daemon without authentication */
polkit.addRule(function(action, subject) {
    if (action.id == "org.libvirt.unix.manage" &&
        subject.isInGroup("kvm")) {
            return polkit.Result.YES;
    }
});


You will need to create the libvirt group and add any users you want to have access to libvirt to that group:
 groupadd libvirt

 sudo gpasswd -a $(whoami) libvirt


Check network interface status:
 sudo virsh net-list --all


If it is inactive start it using:
 sudo virsh net-start default


Now you can use virt-manager manager your virtual machine.


Things to do after installing a Windows VM.


Check and install drivers on your guest Windows VM, probably virtio-win is a nice place to start.


What to do if default network interface is not listed


If virsh net-list is not listing any network interface just reinitialize it with,
sudo virsh net-define /usr/share/libvirt/networks/default.xml


Then just autostart it like so,
sudo virsh net-autostart default 


What to do if you cannot access storage file, and get "Permission denied Error in KVM Libvirt"


Step 1: Edit /etc/libvirt/qemu.conf file:
sudo nano /etc/libvirt/qemu.conf


Step 2: Find the user and group directives. By default, both are set to "root",
 [...] 
 Some examples of valid values are:
 #
 user = "qemu"   # A user named "qemu"
 user = "+0"     # Super user (uid=0)
 user = "100"    # A user named "100" or a user with uid=100
 #
 #user = "root"
 The group for QEMU processes run by the system instance. It can be
 specified in a similar way to user.
 #group = "root"
 [...]

Uncomment both lines and replace root with your username and group with libvirt as shown below:
 [...] 
 Some examples of valid values are:
 #
 user = "qemu"   # A user named "qemu"
 user = "+0"     # Super user (uid=0)
 user = "100"    # A user named "100" or a user with uid=100
 #
 user = "sk"
 The group for QEMU processes run by the system instance. It can be
 specified in a similar way to user.
 group = "libvirt"
 [...]


Step 3: Restart libvirtd service:
 sudo systemctl restart libvirtd


How to extend / increase a Windows Partition on KVM QEMU VM

We have a Windows 7 VM running on Ubuntu KVM. I needed to give the Windows 7 machine more disk space. This turns out to be really easy (when you know how).


Shutdown the VM
 virsh shutdown hostname


Increase the qcow2 image


Find the qcow2 file of the VM and take a backup (just in case).
cp hostname.qcow2 hostname.qcow2.backup
qemu-img resize hostname.qcow2 +100GB


Start the VM
 virsh start hostname


Extend the partition in Window


Windows has a really good partition management utility built into it. Search for disk management
Reference:

Original guide - http://wood1978.dyndns.org/~wood/wordpress/2013/07/22/arch-linux-setup-kvm-with-virt-manager-gui/comment-page-1/
KVM @ Arch Wiki - https://wiki.archlinux.org/index.php/KVM
libvirt @ Arch Wiki - https://wiki.archlinux.org/index.php/Libvirt
QEMU @ Arch Wiki - https://wiki.archlinux.org/index.php/QEMU
Network Interface Status - http://ask.xmodulo.com/network-default-is-not-active.html
Network Interface Troubleshooting - https://blog.programster.org/kvm-missing-default-network
Networking libvirt wiki - https://wiki.libvirt.org/page/Networking#NAT_forwarding_.28aka_.22virtual_networks.22.29
Fedora Wiki - Windows Virtio Drivers - https://stg.fedoraproject.org/wiki/Windows_Virtio_Drivers
Extend disk size Windows partition KVM QEMU VM - https://www.randomhacks.co.uk/how-to-extend-increase-a-windows-partition-on-kvm-qemu-vm/
Increasing a KVM machine disk space - https://serverfault.com/questions/324281/how-do-you-increase-a-kvm-guests-disk-space
Fixing Cannot access storage file, Permission denied Error in KVM Libvirt - https://ostechnix.com/solved-cannot-access-storage-file-permission-denied-error-in-kvm-libvirt/