Ubuntu – the virbr0 interface used for

configurationkvmvirtualization

      virbr0    Link encap:Ethernet  HWaddr a2:17:ea:e3:47:7e  
      inet addr:192.168.122.1  Bcast:192.168.122.255  Mask:255.255.255.0
      UP BROADCAST MULTICAST  MTU:1500  Metric:1
      RX packets:0 errors:0 dropped:0 overruns:0 frame:0
      TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0 
      RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)

can anyone tell me what this interface does and how I can change the IP address? I want to see if it is the reason my guests cannot connect.

Best Answer

The virbr0, or "Virtual Bridge 0" interface is used for NAT (Network Address Translation). It is provided by the libvirt library, and virtual environments sometimes use it to connect to the outside network.

It was likely bundles with a VM software you installed at some point. If you'd like to remove it, and you're sure nothing else depends on it, you can use the following command:

sudo brctl delbr virbr0

(from UbuntuForums)

It is unlikely that the virtual bridge is affecting your guests' ability to connect to the Internet, though.

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enter image description here

Ubuntu – Couldn’t find hvm kernel for Ubuntu tree

Instead of using

 --location /home/me/Downloads/ubuntu-18.10-desktop-amd64.iso

use

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The difference is (from the man page):

-c CDROM , --cdrom=CDROM
File or device use as a virtual CD-ROM device for fully virtualized guests. It can
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Distribution tree installation source. virt-install can recognize certain 
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So the correct command in this case is:

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