[Qemu-devel] How to get a guest IP

[Qemu-devel] How to get a guest IP

[zheng sw]

Host want to get the guest's IP when the host start the guest?

My setting is: debian(2.6.8), qemu, bridge-utils, TUN/TAP. The
guest get a IP from a DHCP server which is in the same subnet whit
host.

My purpose is use bash to run ssh connect to the host, then run
qemu, After the guest is started, the host want to get the guest's
 IP and send to me, but nobody will control the guest. Now I am
puzzle in how the host get the guest IP.

I have try 1. redirect the guest stdio to a terminal. but false,
           2. Use DHCP server bound MAC address with IP, and use
-macaddr set the guest MAC. but I can't control the DHCP server
now.
           3, mount the qemu image, but document say it can't
mounted.
           4. guest use static IP, but I may start several guest
with a image.
           5. use -seral pty, but I can't read the pts.


Thank you!
My english is poor, sorry.

Re: [Qemu-devel] How to get a guest IP

[Henrik Nordstrom]

On Fri, 4 Nov 2005, zheng sw wrote:

> Host want to get the guest's IP when the host start the guest?

Why?

> My setting is: debian(2.6.8), qemu, bridge-utils, TUN/TAP. The
> guest get a IP from a DHCP server which is in the same subnet whit
> host.

Ok.

> My purpose is use bash to run ssh connect to the host, then run
> qemu, After the guest is started, the host want to get the guest's
> IP and send to me, but nobody will control the guest. Now I am
> puzzle in how the host get the guest IP.

The most obvious way would be to use dynamic DNS updates, supported by 
most DHCP servers, automatically registering the guest host name in DNS.

Another way is to have a init script in the guest to somehow tell the host 
what IP address it has.

Regards
Henrik

Re: [Qemu-devel] How to get a guest IP

[shunwen]

On 五, 2005-11-04 at 15:52 +0100, Henrik Nordstrom wrote:
> On Fri, 4 Nov 2005, zheng sw wrote:
> 
> > Host want to get the guest's IP when the host start the guest?
> 
> Why?
Beause I want to login the guest with ssh in another computer, and do
some test in it.
> 
> > My setting is: debian(2.6.8), qemu, bridge-utils, TUN/TAP. The
> > guest get a IP from a DHCP server which is in the same subnet whit
> > host.
> 
> Ok.
> 
> > My purpose is use bash to run ssh connect to the host, then run
> > qemu, After the guest is started, the host want to get the guest's
> > IP and send to me, but nobody will control the guest. Now I am
> > puzzle in how the host get the guest IP.
> 
> The most obvious way would be to use dynamic DNS updates, supported by 
> most DHCP servers, automatically registering the guest host name in DNS.
I think it's difficult to do such actions in program or script.
> 
> Another way is to have a init script in the guest to somehow tell the host 
> what IP address it has.
In this way, the guest don't know the host IP except I send a message to
guest when qemu run, Beause I may run qemu in different computer. When
read the document, I can't find any way to send a message to guest in
the command line or script.

The best way I think is get the output of guest when it booting. I only
find the option of redirect the guest output use -serial dev. But I
can't read the output when use -serial pty. Is any other ways?

thank you!
Best Regards
Zheng SW
> 
> Regards
> Henrik