Hardy KVM Failed to add tap interface

[dendrobates]

your user needs to be in the libvirtd and kvm groups for this to work.

The #ubuntu-virt channel on FreeNode is a good place to get help. The developers hang out there.

Rick

[srodden]

My user is in those two groups. Thanks for the tip on the channel. Will ask there.

[deadguy]

I'm getting the same error, but running as root does not help for me. Also, it's happening on a per-vm basis. I have one VM which starts up just fine as any user, and another which won't start up at all.

[cfmunster]

I have the same problem and did some searching. This issue has been logged as a bug in Hardy:

https://bugs.launchpad.net/ubuntu/+s...er/+bug/247677

[IntuitiveNipple]

If you're using tun/tap the user needs to be a member of the tun group and the tun device needs to give the tun group permissions too.

As it happens I've just documented these steps as part of an article on how to configure VDE networking for KVM.

Try the steps in the sections "Add User(s) to Groups" and "Give New Devices tun Group Ownership" in my Wiki article.

Because the udev rule has changed you can either go through a full reboot or manually change the permissions with:

sudo chown :tun /dev/net/tun
ls -l /dev/net/tun
crw-rw---- 1 root tun 10, 200 2008-07-02 10:49 /dev/net/tun

and then do a log-out/log-in to refresh the user's groups membership.

This works on Gutsy and Hardy at least, that I know of.