Re: [libvirt] Trouble starting a QEMU guest with IPv6 VNC address
On 10/27/2009 01:47 PM, Kaitlin Rupert wrote:
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.
Not exactly specific to qemu. Many other protocols use it (eg SIP,
pretty much any URL - see section 3.2.2 of RFC3986). Basically, anywhere
the IP address might have a port tacked onto it with ":n" syntax *needs*
to have the brackets and, due to this precedent, many other places
accept it anyway.
My opinion would be that in cases where the port may be specified
URL-style as part of the address (I haven't looked to see if that's the
case here), then the brackets should be required; if port cannot be
specified using ":n" syntax, then brackets should NOT be required, but
should be accepted.
(In practice, I found that having some places where brackets were
required and some where it wasn't necessitated lots of extra code and
was just a nuisance all around (even worse to have places where brackets
weren't even accepted).
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!