Re: [Qemu-discuss] how to disable DHCP client on qemu

[Medi Montaseri]

I don't think we are using libvert...here is the actual call to 
runqemu(1) and sub-sequent call to qemu-system-x86_64.

FYI, I am requesting two serial devices and two network interface 
devices (tap0 and tap1)


=== About to run [runqemu qemux86-64  serial  kvm  notap  qemuparams="-m 256 -device 
virtio-serial -chardev socket,path=.//tty0,server,nowait,id=tty0 -device 
virtserialport,chardev=tty0,name=tty0 -chardev socket,path=.//tty1,server,nowait,id=tty1 
-device virtserialport,chardev=tty1,name=tty1  -net 
nic,model=virtio,macaddr=52:54:00:12:34:124 -net tap,ifname=tap0,script=no,downscript=no  
-net nic,model=virtio,macaddr=52:54:00:12:34:125 -net 
tap,ifname=tap1,script=no,downscript=no  "]

Running qemu-system-x86_64...
/home/medim/work3/build/tmp-glibc/sysroots/x86_64-linux/usr/bin/qemu-system-x86_64
     -kernel 
/home/medim/work3/build/tmp-glibc/deploy/images/qemux86-64/bzImage-qemux86-64.bin
     -cpu kvm64 -drive 
file=/home/medim/work3/build/tmp-glibc/deploy/images/qemux86-64/og-image-consoleserver-dev-qemux86-64-20180126232855.rootfs.ext4,if=virtio,format=raw
     -show-cursor
     -usb
     -usbdevice tablet
     -vga vmware -no-reboot -serial stdio -enable-kvm -m 256
     -device virtio-serial
     -chardev socket,path=.//tty0,server,nowait,id=tty0 -device 
virtserialport,chardev=tty0,name=tty0
     -chardev socket,path=.//tty1,server,nowait,id=tty1 -device 
virtserialport,chardev=tty1,name=tty1
     -net nic,model=virtio,macaddr=52:54:00:12:34:124 -net 
tap,ifname=tap0,script=no,downscript=no
     -net nic,model=virtio,macaddr=52:54:00:12:34:125 -net 
tap,ifname=tap1,script=no,downscript=no
     -append "vga=0 uvesafb.mode_option=640x480-32 root=/dev/vda rw mem=256M ip=off 
oprofile.timer=1 rootfstype=ext4 console=ttyS0"

Note how I have set "ip=off" (similar to ip=none) and I am expecting qemu to 
stay off of network configuration, I'll do it later in my boot scripts

Thanks
Medi



On 01/23/2018 11:23 PM, Thomas Huth wrote:
>   Hi,
>
> On 23.01.2018 21:01, Medi Montaseri wrote:
> > I am using qemu-system-x86_64
> > (x86_64-linux/qemu-native/2.5.0-r1/qemu-2.5.0 ) and multiple network
> > interface and in a bridged mode with the host.
> [...]
> > I don't want qemu to run dhcpc as our own boot scripts will do
> > static/dynamic configurations on the tap devices.
> >
> > 1) Is there a command line option that I can use to instruct qemu not to
> > run any DHCP client ?
> Are you sure that the DHCP service is coming from QEMU? As far as I
> know, QEMU only provides DHCP for the "-netdev user" interfaces, but not
> for tap / bridge.
>
> Are you using libvirt or something similar on top of QEMU? If so, the
> DHCP service might be provided by that layer instead, see for example:
> https://wiki.libvirt.org/page/VirtualNetworking#DNS_.26_DHCP
>
>   HTH,
>    Thomas