Re: multiple qemu hosts

[Vijay Sankar]

Matthias Pfeifer wrote:
Hello
On Tue, 02 Feb 2010 05:35:28 -0600
Vijay Sankar <vsan...@foretell.ca> wrote:

Matthias Pfeifer wrote:
Hello list

I am trying to get multiple qemu guests on 
host machine running. Host and guests are running
openbsd 4.6 in sync with the patch brunch.

The Host IP is: 192.168.102.110
The guest should have: 192.168.102.111, 192.168.102.112 .. 
and so on. All in the same network, using the same DNS server
and gateway.

I have read /usr/local/share/doc/qemu/README.OpenBSD
and tried the samples in the tap section. This works
fine for one host.

For example, this is working well for one host:

ifconfig tun0 link0
ifconfig bridge0 create
brconfig bridge0 add tun0 add rl0 up

qemu -net nic,macaddr=52:54:00:12:35:10 \
     -net tap,fd=3 \
     -name Host1 \
     -no-fd-bootchk \
     -hda Host1/system.img 3<>/dev/tun0


Then, I'd like to doing this:

ifconfig tun1 link0
ifconfig bridge1 create
brconfig bridge1 add tun1 add rl0 up

qemu -net nic,macaddr=52:54:00:12:35:11 \ ## MAC changed
     -net tap,fd=4 \   ## fd changed
     -name Host1 \
     -no-fd-bootchk \
     -hda Host2/system.img 4<>/dev/tun1  ## tun interface changed


But this fails. Is there a way to do something like this
without adding a real NIC?


Thanks in advance! 

Matthias

NOTE: sudo calls closefrom(2).  In order to have more than one fd passed
         tap interface, a line to sudoers akin to:

                 Defaults closefrom_override

         then calling sudo via 'sudo -C 5 -u $USER qemu ..' is required.
         See sudoers(5) and sudo(8) for details.

--
Vijay Sankar, M.Eng., P.Eng.
ForeTell Technologies Limited
59 Flamingo Avenue, Winnipeg, MB, Canada R3J 0X6
Phone: (204) 885-9535, E-Mail: vsan...@foretell.ca


I have added "Defaults closefrom_override" to /etc/sudoers.
So i am using the tun0 for the second qemu host:

sudo sh -c " sudo -C 5 -u qemu qemu -net nic,macaddr=52:54:00:12:35:10 \
     -net tap,fd=3 -name DSB -no-fd-bootchk -hda host1/system.img 3<>/dev/tun0"

Working fine. Then the second:

sudo sh -c " sudo -C 5 -u qemu qemu -net nic,macaddr=52:54:00:12:35:10 \
     -net tap,fd=4 -name DSB -no-fd-bootchk -hda host1/system.img 4<>/dev/tun0"


this gives me a " cannot create /dev/tun0: Device busy "


Looks like you have the same MAC. I am not able to test this right now 
but will try to see if I can repeat this error.

--
Vijay Sankar, M.Eng., P.Eng.
ForeTell Technologies Limited
59 Flamingo Avenue, Winnipeg, MB, Canada R3J 0X6
Phone: (204) 885-9535, E-Mail: vsan...@foretell.ca