[libvirt] Trouble starting a QEMU guest with IPv6 VNC address

[Kaitlin Rupert]

It looks like specifying an address of [::1] instead of ::1 will work. 
However, that seems like a bug.  The bracket syntax is specific to qemu, 
which means the user needs to have prior knowledge of this.

Kaitlin Rupert wrote:
> Hello,
> 
> I am trying to start a QEMU guest with an IPv6 VNC address.  I can 
> specify the address and start the guest, but the VNC port shows up under 
> the IPv4 list:
> 
> # virsh dumpxml domU1 | grep graphics
>     <graphics type='vnc' port='5900' autoport='no' listen='::1' 
> keymap='en-us'/>
> 
> # cat /proc/net/tcp | grep 170C
>    2: 00000000:170C 00000000:0000 0A 00000000:00000000 00:00000000 
> 00000000     0        0 621103 1 ffff88007a043a80 299 0 0 2 -1
> 
> # cat /proc/net/tcp6 | grep 170C
> #
> 
> # ps -ef | grep qemu
> root     16451     1 43 04:17 ?        00:00:18 
> /usr/bin/qemu-system-x86_64 -S -M pc -m 128 -smp 1 -name domU1 -uuid 
> 2aebe290-d1ed-11dd-90eb-001a64bc024c -monitor pty -pidfile 
> /var/run/libvirt/qemu//domU1.pid -no-acpi -boot c -drive 
> file=/tmp/default-kvm-dimage,if=ide,index=0,boot=on -net 
> nic,macaddr=11:22:33:aa:bb:cc,vlan=0 -net tap,fd=17,vlan=0 -serial none 
> -parallel none -usb -vnc ::1:0 -k en-us
> 
> I started the same guest manually, but I appended an ",ipv6' flag to the 
> vnc option (see below).  With this change, the port shows up in the IPv6 
> list.
> 
> # /usr/bin/qemu-system-x86_64 -M pc -m 128 -smp 1 -name domU1 -uuid 
> 2aebe290-d1ed-11dd-90eb-001a64bc024c -monitor pty -pidfile 
> /var/run/libvirt/qemu//domU1.pid -no-acpi -boot c -drive 
> file=/tmp/default-kvm-dimage,if=ide,index=0,boot=on -net 
> nic,macaddr=11:22:33:aa:bb:cc,vlan=0 -net tap,fd=17,vlan=0 -serial none 
> -parallel none -usb -vnc ::1:0,ipv6 -k en-us
> 
> # cat /proc/net/tcp6 | grep 170C
>    2: 00000000000000000000000000000000:170C 
> 00000000000000000000000000000000:0000 0A 00000000:00000000 00:00000000 
> 00000000     0        0 621485 1 ffff88007a30ad00 299 0 0 2 -1
> 
> # cat /proc/net/tcp | grep 170C
> #
> 
> I'd like to fix the qemu driver so that it specifies this flag, but I am 
> unsure whether a guest XML change or some other change is appropriate 
> here.  Would it be better to have the qemu driver code do some detection 
> on the address that is passed in?
> 
> Thanks!


-- 
Kaitlin Rupert
IBM Linux Technology Center
kaitlin at linux.vnet.ibm.com