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mininet/util/vm/build.py
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Python
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#!/usr/bin/python
"""
build.py: build a Mininet VM
Basic idea:
prepare
- download cloud image if it's missing
- write-protect it
build
-> create cow disk for vm
-> boot it in qemu/kvm with text /serial console
-> install Mininet
test
-> make codecheck
-> make test
release
-> shut down VM
-> shrink-wrap VM
-> upload to storage
Notes du jour:
- our infrastructure is currently based on 12.04 LTS, so we
can't rely on cloud-localds which is only in 12.10+
- as a result, we should download the tar image, extract it,
and boot with tty0 as the console (I think)
- and we'll manually add the mininet user to it
- and use pexpect to interact with it on the serial console
Something to think about:
Maybe download the cloud image and customize it so that
it is an actual usable/bootable image???
"""
import os
from os.path import exists, splitext
from glob import glob
from urllib import urlretrieve
from subprocess import check_output, call, Popen, PIPE
from tempfile import mkdtemp, NamedTemporaryFile
from sys import exit
from time import time
# boot can be slooooow!!!! need to debug/optimize somehow
TIMEOUT=120
VMImageDir = os.environ[ 'HOME' ] + '/vm-images'
ImageURLBase = {
'raring-server-amd64':
'http://cloud-images.ubuntu.com/raring/current/'
'raring-server-cloudimg-amd64'
}
def run( cmd, **kwargs ):
"Convenient interface to check_output"
print cmd
cmd = cmd.split()
return check_output( cmd, **kwargs )
def srun( cmd, **kwargs ):
"Run + sudo"
return run( 'sudo ' + cmd, **kwargs )
# Install necessary packages
print '* Installing package dependencies'
packages = ( )
run( 'sudo apt-get -y update' )
run( 'sudo apt-get install -y'
' kvm cloud-utils genisoimage qemu-kvm qemu-utils'
' e2fsprogs '
' landscape-client'
' python-setuptools' )
run( 'sudo easy_install pexpect' )
import pexpect
def popen( cmd ):
"Convenient interface to popen"
print cmd
cmd = cmd.split()
return Popen( cmd )
def remove( fname ):
"rm -f fname"
return run( 'rm -f %s' % fname )
def imageURL( image ):
"Return base URL for VM image"
return ImageURLBase[ image ]
def imagePath( image ):
"Return base pathname for VM image files"
url = imageURL( image )
fname = url.split( '/' )[ -1 ]
path = os.path.join( VMImageDir, fname )
return path
def fetchImage( image, path=None ):
"Fetch base VM image if it's not there already"
if not path:
path = imagePath( image )
tgz = path + '.tar.gz'
disk = path + '.img'
kernel = path + '-vmlinuz-generic'
floppy = path + '-floppy'
if exists( disk ) and exists( kernel ):
print '* Found', disk, 'and', kernel
else:
dir = os.path.dirname( path )
run( 'mkdir -p %s' % dir )
if not os.path.exists( tgz ):
url = imageURL( image ) + '.tar.gz'
print '* Retrieving', url
urlretrieve( url, tgz )
print '* Extracting', tgz
run( 'tar -C %s -xzf %s' % ( dir, tgz ) )
# Make sure Mininet user is there
os.chmod( disk, 0664 )
addMininetUser( disk )
# Write-protect disk image so it remains somewhat pristine;
# We will not use it directly but will use a COW disk
print '* Write-protecting disk image', disk
os.chmod( disk, 0444 )
return disk, kernel
def addTo( file, line ):
"Add line to file if it's not there already"
if call( [ 'sudo', 'grep', line, file ] ) != 0:
call( 'echo "%s" | sudo tee -a %s' % ( line, file ), shell=True )
def disableCloud( bind ):
"Disable cloud junk for disk mounted at bind"
print '* Disabling cloud startup scripts'
modules = glob( '%s/etc/init/cloud*.conf' % bind )
for module in modules:
path, ext = splitext( module )
override = path + '.override'
call( 'echo manual | sudo tee ' + override, shell=True )
def addMininetUser( img ):
"Add mininet user/group to root filesystem image"
print '* Adding mininet user to', img
# 1. We bind-mount / into a temporary directory, and
# then mount the volume's /etc and /home on top of it!
bind = mkdtemp()
mnt = mkdtemp()
srun( 'mount -B / ' + bind )
srun( 'mount %s %s' % ( img, mnt ) )
srun( 'mount -B %s/etc %s/etc' % ( mnt, bind ) )
srun( 'mount -B %s/home %s/home' % ( mnt, bind ) )
def chroot( cmd ):
"Chroot into bind mount and run command"
call( 'sudo chroot %s ' % bind + cmd, shell=True )
# 2. Next, we delete any old mininet user and add a new one
chroot( 'deluser mininet' )
chroot( 'useradd --create-home mininet' )
print '* Setting password'
call( 'echo mininet:mininet | sudo chroot %s chpasswd -c SHA512'
% bind, shell=True )
# 2a. Add mininet to sudoers
addTo( bind + '/etc/sudoers', 'mininet ALL=NOPASSWD: ALL' )
# 2b. Disable cloud junk
disableCloud( bind )
chroot( 'sudo update-rc.d landscape-client disable' )
# 2c. Add serial getty
print '* Adding getty on ttyS0'
chroot( 'cp /etc/init/tty1.conf /etc/init/ttyS0.conf' )
chroot( 'sed -i "s/tty1/ttyS0/g" /etc/init/ttyS0.conf' )
# 3. Lastly, we umount and clean up everything
run( 'sync' )
srun( 'umount %s/etc ' % bind )
srun( 'umount %s/home ' % bind )
srun( 'umount %s' % bind )
srun( 'umount ' + mnt )
run( 'rmdir ' + mnt )
# 4. Just to make sure, we check the filesystem
run( 'e2fsck -y ' + img )
def makeCOWDisk( image ):
"Create new COW disk for image"
disk, kernel = fetchImage( image )
cow = disk + '.qcow2'
print '* Creating COW disk', cow
remove( cow )
run( 'qemu-img create -f qcow2 -b %s %s' % ( disk, cow ) )
print '* Resizing COW disk and file system'
run( 'qemu-img resize %s +8G' % cow )
srun( 'modprobe nbd')
srun( 'qemu-nbd -c /dev/nbd0 ' + cow )
srun( 'e2fsck -fy /dev/nbd0' )
srun( 'resize2fs /dev/nbd0' )
srun( 'qemu-nbd -d /dev/nbd0' )
return cow, kernel
def boot( cow, kernel ):
"""Boot qemu/kvm with a COW disk and local/user data store
returns: popen object to qemu process"""
if 'amd64' in cow:
kvm = 'qemu-system-x86_64'
elif 'i386' in cow:
kvm = 'qemu-system-i386'
else:
print "Error: can't discern CPU for image", cow
exit
# was -nographic
# was -net=%net
# ' -net nic,model=virtio'
# ' -netdev tap,id=mininet0,ifname=%s,script=no ' % tap +
cmd = [ 'sudo', kvm,
'-machine', 'accel=kvm',
'-nographic',
'-m', '512',
'-k', 'en-us',
'-kernel', kernel,
'-drive', 'file=%s,if=virtio' % cow,
'-append',
' "root=/dev/vda'
' init=/sbin/init'
# ' init=/usr/lib/cloud-init/uncloud-init'
# ' ds=nocloud'
# ' --verbose'
' console=ttyS0"'
]
cmd = ' '.join( cmd )
print '* STARTING VM'
print cmd
vm = pexpect.spawn( cmd, timeout=TIMEOUT )
logfile = NamedTemporaryFile( prefix='mn-build-expect' )
print '* Logging results to', logfile.name
vm.logfile_read = logfile
return vm, logfile
def interact( vm ):
"Interact with vm, which is a pexpect object"
prompt = '\$ '
print '* Waiting for login prompt'
vm.expect( 'login: ' )
print '* Logging in'
vm.sendline( 'mininet' )
print '* Waiting for password prompt'
vm.expect( 'Password: ' )
print '* Sending password'
vm.sendline( 'mininet' )
print '* Waiting for login...'
vm.expect( prompt )
print '* Sending hostname command'
vm.sendline( 'hostname' )
print '* Waiting for output'
vm.expect( prompt )
print '* Fetching Mininet VM install script'
vm.sendline( 'wget '
'https://raw.github.com/mininet/mininet/master/util/vm/'
'install-mininet-vm.sh' )
vm.expect( prompt )
print '* Running VM install script'
vm.sendline( 'bash install-mininet-vm.sh' )
print '* Waiting for script to complete... '
vm.expect( 'Done preparing Mininet' )
print '* Completed successfully'
vm.expect( prompt )
print '* Testing Mininet'
vm.sendline( 'sudo mn --test pingall' )
vm.expect( '0% dropped' )
print '* Basic test succeeded'
vm.expect( prompt )
print '* Running make test'
vm.sendline( 'cd ~/mininet; sudo make test' )
vm.expect( 'OK' )
print '* Basic test succeeded'
vm.expect( 'OK' )
print '* Hi-Fi test succeeded'
vm.expect( prompt )
print '* Shutting down'
vm.sendline( 'sync; sudo shutdown -h now' )
print '* Waiting for EOF/shutdown'
vm.read()
print '* Interaction complete'
image = 'raring-server-amd64'
start = time()
cow, kernel = makeCOWDisk( image )
print '* VM image for', image, 'created as', cow
vm, logfile = boot( cow, kernel )
interact( vm )
logfile.close()
end = time()
elapsed = end - start
print '* Results logged to', logfile.name
print '* Completed in %.2f seconds' % elapsed
print '* DONE!!!!! :D'