qemu builds a basic virtual machine

Use qemu to create a virtual machine 1. Need the kernel file bzImage 2. Make the image of the operating system hda.img Kernel compilation reference: http://haoningabc.iteye.com/blog/2237569 To make a simple image, you need to use https://github. com/killinux/jslinux_reversed specifically builds a 120M streamlined operating system, the etch version of debian requires support for network commands such as ip, ifconfig, dhclient, etc. The establishment method, this debootstrap command may not work in China, go to aws to operate it. The establishment method: in the ubuntu operating system superior

cd / opt /  
debootstrap        --variant=minbase         --include=dhcp-client,ssh,vim,make,psmisc,mini-httpd,net-tools,iproute,iputils-ping,procps,telnet,iptables,wget,tcpdump,curl,gdb,binutils,gcc,libc6-dev,lsof,strace         --exclude=locales,aptitude,gnupg,cron,udev,tasksel,rsyslog,groff-base,manpages,gpgv,man-db,apt,debian-archive-keyring,sysv-rc,sysvinit,insserv,python2.6         --arch i386         etch etch         'http://archive.debian.org/debian'  

Get
/opt/etch
as the file of the required operating system. Note that the package selected here contains basic network commands such as ip, dhclient, etc.

Download the tools for generating mirrors
mainly use https://github.com/killinux/jslinux_reversed/blob/master /contrib/createimage.sh

cd / var / www / html /
git clone https://github.com/killinux/jslinux_reversed
mv /opt/etch /var/www/html/jslinux_reversed/contrib/squeeze  
./createimage.sh  

Generate hda.img

file By default when linux starts, /sbin/init is called first,
so check the correctness of the init file
mkdir hda
mount -o loop hda.img hda
vim hda/sbin/init

#!/bin/sh  
show_boot_time 2>/dev/null  
echo "JSLinux started, initializing..."  
export PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin  
export HOME=/root  
export TERM=vt100  
mount -n -t proc /proc /proc  
mount -n -t sysfs /sys /sys  
mount -n -t devpts devpts /dev/pts  
mount -n -t tmpfs /tmp /tmp  
mkdir -p "/tmp/root"  
ip link set up dev lo  
main() {  
    echo >/dev/clipboard  
    while :; do  
        setsid sh -c "exec bash 0<>/dev/ttyS0 1>&0 2>&0"  
    done  
}  
#. /dev/clipboard  
main "$@"  

Comment out #. /dev/clipboard 
Note that if the startup fails, you may need to add
/sbin/mdev -s
to initialize the files under /dev. The key point
here is to mount the three file systems of /proc /sys and /dev

Yes With the bzImage kernel and hda.img image
, you can create a virtual machine

qemu-system-i386 -kernel bzImage -drive file=hda.img,if=ide,cache=none -append "console=ttyS0 root=/dev/sda rw rdinit=/sbin/init notsc=1"  -nographic 

or

qemu-system-i386 -kernel bzImage -hda  hda.img -append "console=ttyS0 root=/dev/sda rw rdinit=/sbin/init notsc=1"  -nographic  

-hda or -drive mode
cache parameter can use
writethrough write-through mode: write data to disk cache while mobilizing write to write data
writeback writeback mode: write data to disk cache and return
none to close cache

btw , if you don't want to destroy the original hda.img and
use incremental build vm ,
you can specify hda.img as backing_file

qemu-img create -f qcow2 -o backing_file=hda.img hda_hasbacking_file.qcow2

That is, hda.img is used as the basic template, and
the new hda_hasbacking_file.qcow2 saves the incremental part
of hda.img. The vm created by hda_hasbacking_file.qcow2 will not cause damage to the original image

qemu-system-i386 -kernel bzImage -drive file=hda_hasbacking_file.qcow2,if=ide,cache=none -append "console=ttyS0 root=/dev/sda rw rdinit=/sbin/init notsc=1"  -nographic

If you add -boot order=dc, menu=on
can control the boot order, and whether to display the boot menu
d is the optical drive, c is the first hard disk

If you add a network, use the -net parameter

qemu-system-i386 -kernel  bzImage -drive file=hda_hasbacking_file.qcow2,if=ide,cache=none -append "console=ttyS0 root=/dev/sda rw rdinit=/sbin/init notsc=1"  -nographic -boot order=dc,menu=on -net nic,vlan=0,macaddr=52:54:00:12:34:22,model=e1000,addr=08 -net tap,ifname=tap1,script=no,downscript=no

-net nic is a necessary parameter to indicate that this is a network card configuration
vlan indicates the blan number, the default 0
macaddr is the mac address, after entering the virtual machine
ctrl+ac switch to monitor mode
info network to view the network card

root@(none):/# QEMU 2.5.1 monitor - type 'help' for more information
(qemu) info network
hub 0
 \ hub0port1: tap.0: index=0,type=tap,ifname=tap1,script=no,downscript=no
 \ hub0port0: e1000.0: index=0,type=nic,model=e1000,macaddr=52:54:00:12:34:22
(qemu)

You can see that the mac address
52:54:00:12:34:22
is the model specified when we created the vm

as the network card type. You can check qemu to see what the types of network cards are.

qemu-system-i386 -net nic,model=?
qemu: Supported NIC models: ne2k_pci,i82551,i82557b,i82559er,rtl8139,e1000,pcnet,virtio

For more network-related information, you can refer to Create a virtual machine with qemu by
bridging : http://haoningabc.iteye.com/blog/2306736 Create a virtual machine
with qemu by NAT :
http://haoningabc.iteye.com/blog /2306952