Create virbr0 for virsh

Question

Okay so I have an html form in Add.html. When I click submit, I would like the data to be added to my database via php and then return to the same form with "instance added" or "failed blah blah."

The only way I know how is to set the form action to a separate php file and call that - but then the php file renders and I do not return to the same form.

I would like to not have to add a "return to form" button and would prefer to return to the form on submit with a status message.

Any better ways to do this?

Solution 1

The reason was insufficient rights to use bridge from non-root user.

Documentation states that:

libvirt defaults to qemu:///session for non-root. So from <youruser> you'll need to do:

$ virsh --connect qemu:///system list --all

It wasn't clear that you have to specify it for installation, and when you would do that. It turns out it's a required command line option for non-root user.

Correct command to install a new VM with networking should include following:

virt-install --connect qemu:///system .......

Or it's also possible to install it directly from root user

Solution 2

This is how it should work:

# cat /tmp/virt-net-example.xml
<network connections='9'>
  <name>some-virt-net</name>
  <uuid>530f11c4-617b-447c-bdba-704f34374277</uuid>
  <bridge name='virbr42' stp='on' delay='0'/>
  <mac address='42:13:37:23:21:87'/>
  <ip address='172.20.42.254' netmask='255.255.255.0'>
    <dhcp>
      <range start='172.20.42.1' end='172.20.42.42'/>
    </dhcp>
  </ip>
</network>
# virsh net-define /tmp/virt-net-example.xml
# virsh net-start some-virt-net
Network some-virt-net started

# brctl show virbr42
bridge name     bridge id               STP enabled     interfaces
virbr42         8000.421337232187       yes             virbr42-nic

# link show virbr42-nic
99: virbr42-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc fq_codel master virbr42 state DOWN mode DEFAULT group default qlen 1000
    link/ether 42:13:37:23:21:87 brd ff:ff:ff:ff:ff:ff

Tested just now on FC22 against libvirt 1.2.13

Comments

[shaunsantacruz]

Check out this answer

[Kyle Brown]

Can you explain, or link an explanation on how to redirect in php? I assume you mean set the form action to a separate file, run the db stuff, then redirect with flash message

[kingtut007]

are you using a php framework? Its easier on php frameworks. Read up on php.net/manual/en/function.header.php

[kingtut007]

This breaks MVC pattern conventions.

[thepiyush13]

care to explain, please ?

[kingtut007]

Its not preferable to have template code alongside php code. The following script up there wont work first of all because you indicated that you are running it from an .html file (and not a php file) - so you cant basically parse php syntax in that file. Moreover, by mvc coding standards - it means Model View Controller - you should have the template (view) solely responsible for displaying data given to it from the controller and not mishmashing everything together.

[thepiyush13]

I agree but on the other hand I did not see OP describing that he is using a MVC framework like CI , in addition if you notice the file name is yourpage.php so it will work just fine, anyway good points, thanks

[Igor Artamonov]

Tried, same result, same error. So maybe it's not because of non-existing virbr0, but something else related to that bridge? because it works without specifying --network option. Something is wrong there, but Transport endpoint is not connected doesn't make it clear

[dyasny]

I use this all the time on RHEL, you might be running into a Debian specific bug.

[Igor Artamonov]

Do you know any way to debug it? virsh logs/output are non-informative, and Transport endpoint is not connected doesn't give any clue. -d 0 doesn't provide additional log to that error message

[dyasny]

try to simply create a VM with virt-manager and attach it to br0, see if that works. If it does, I'd simply stick to the manual creation way, or if you really need automation, use virt-builder instead of virt-install. It's way less buggy, especially and that's important on non-RH distros that don't really do any quality testing like Debian

[Igor Artamonov]

not sure what you mean by attach it to br0. I've tried to create simple VM without networking, but if I edit its xml and add bridge network (there's example in the question) it failed to run. I don't know about other way to attach it to br0. I'll try virt-builder, thanks

[dyasny]

This is probably a bug in your build of libvirt. I am adding an example of a working interface definition you can try yourself. The brctl output seems to be in good order

[Igor Artamonov]

thanks. could you elaborate it a little more? what so you think should be modified in my config to make it working? because it doesn't look like adding mac address will help. so there should be something important in your example, but I don't understand what exactly

[phg]

“what so you think should be modified in my config” -- not the config, but let libvirt create the bridge. It will do that on its own. In your VM definition you then reference the bridge as <target dev='vnet42'/> in the interface section.