Merge pull request #315 from cdburkard/patches/fix_bindpy
Added support for mount namespaces in bind.py
This commit is contained in:
lantz
+42
-167
@@ -1,197 +1,72 @@
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#!/usr/bin/python
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"""
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bind.py: Bind mount prototype
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bind.py: Bind mount example
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This creates hosts with private directories as desired.
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This creates hosts with private directories that the user specifies.
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These hosts may have persistent directories that will be available
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across multiple mininet session, or temporary directories that will
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only last for one mininet session. To specify a persistent
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directory, add a tuple to a list of private directories:
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[ ( 'directory to be mounted on', 'directory to be mounted' ) ]
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String expansion may be used to create a directory template for
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each host. To do this, add a %(name)s in place of the host name
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when creating your list of directories:
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[ ( '/var/run', '/tmp/%(name)s/var/run' ) ]
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If no persistent directory is specified, the directories will default
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to temporary private directories. To do this, simply create a list of
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directories to be made private. A tmpfs will then be mounted on them.
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You may use both temporary and persistent directories at the same
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time. In the following privateDirs string, each host will have a
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persistent directory in the root filesystem at
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"/tmp/(hostname)/var/run" mounted on "/var/run". Each host will also
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have a temporary private directory mounted on "/var/log".
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[ ( '/var/run', '/tmp/%(name)s/var/run' ), '/var/log' ]
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This example has both persistent directories mounted on '/var/log'
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and '/var/run'. It also has a temporary private directory mounted
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on '/var/mn'
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"""
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from mininet.net import Mininet
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from mininet.node import Host
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from mininet.node import Host, HostWithPrivateDirs
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from mininet.cli import CLI
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from mininet.util import errFail, quietRun, errRun
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from mininet.topo import SingleSwitchTopo
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from mininet.log import setLogLevel, info, debug
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from os.path import realpath
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from functools import partial
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# Utility functions for unmounting a tree
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MNRUNDIR = realpath( '/var/run/mn' )
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def mountPoints():
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"Return list of mounted file systems"
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mtab, _err, _ret = errFail( 'cat /proc/mounts' )
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lines = mtab.split( '\n' )
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mounts = []
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for line in lines:
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if not line:
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continue
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fields = line.split( ' ')
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mount = fields[ 1 ]
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mounts.append( mount )
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return mounts
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def unmountAll( rootdir=MNRUNDIR ):
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"Unmount all mounts under a directory tree"
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rootdir = realpath( rootdir )
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# Find all mounts below rootdir
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# This is subtle because /foo is not
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# a parent of /foot
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dirslash = rootdir + '/'
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mounts = [ m for m in mountPoints()
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if m == dir or m.find( dirslash ) == 0 ]
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# Unmount them from bottom to top
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mounts.sort( reverse=True )
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for mount in mounts:
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debug( 'Unmounting', mount, '\n' )
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_out, err, code = errRun( 'umount', mount )
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if code != 0:
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info( '*** Warning: failed to umount', mount, '\n' )
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info( err )
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class HostWithPrivateDirs( Host ):
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"Host with private directories"
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mnRunDir = MNRUNDIR
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def __init__(self, name, *args, **kwargs ):
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"""privateDirs: list of private directories
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remounts: dirs to remount
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unmount: unmount dirs in cleanup? (True)
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Note: if unmount is False, you must call unmountAll()
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manually."""
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self.privateDirs = kwargs.pop( 'privateDirs', [] )
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self.remounts = kwargs.pop( 'remounts', [] )
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self.unmount = kwargs.pop( 'unmount', True )
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Host.__init__( self, name, *args, **kwargs )
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self.rundir = '%s/%s' % ( self.mnRunDir, name )
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self.root, self.private = None, None # set in createBindMounts
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if self.privateDirs:
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self.privateDirs = [ realpath( d ) for d in self.privateDirs ]
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self.createBindMounts()
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# These should run in the namespace before we chroot,
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# in order to put the right entries in /etc/mtab
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# Eventually this will allow a local pid space
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# Now we chroot and cd to wherever we were before.
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pwd = self.cmd( 'pwd' ).strip()
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self.sendCmd( 'exec chroot', self.root, 'bash -ms mininet:'
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+ self.name )
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self.waiting = False
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self.cmd( 'cd', pwd )
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# In order for many utilities to work,
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# we need to remount /proc and /sys
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self.cmd( 'mount /proc' )
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self.cmd( 'mount /sys' )
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def mountPrivateDirs( self ):
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"Create and bind mount private dirs"
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for dir_ in self.privateDirs:
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privateDir = self.private + dir_
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errFail( 'mkdir -p ' + privateDir )
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mountPoint = self.root + dir_
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errFail( 'mount -B %s %s' %
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( privateDir, mountPoint) )
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def mountDirs( self, dirs ):
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"Mount a list of directories"
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for dir_ in dirs:
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mountpoint = self.root + dir_
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errFail( 'mount -B %s %s' %
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( dir_, mountpoint ) )
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@classmethod
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def findRemounts( cls, fstypes=None ):
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"""Identify mount points in /proc/mounts to remount
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fstypes: file system types to match"""
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if fstypes is None:
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fstypes = [ 'nfs' ]
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dirs = quietRun( 'cat /proc/mounts' ).strip().split( '\n' )
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remounts = []
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for dir_ in dirs:
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line = dir_.split()
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mountpoint, fstype = line[ 1 ], line[ 2 ]
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# Don't re-remount directories!!!
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if mountpoint.find( cls.mnRunDir ) == 0:
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continue
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if fstype in fstypes:
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remounts.append( mountpoint )
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return remounts
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def createBindMounts( self ):
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"""Create a chroot directory structure,
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with self.privateDirs as private dirs"""
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errFail( 'mkdir -p '+ self.rundir )
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unmountAll( self.rundir )
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# Create /root and /private directories
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self.root = self.rundir + '/root'
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self.private = self.rundir + '/private'
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errFail( 'mkdir -p ' + self.root )
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errFail( 'mkdir -p ' + self.private )
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# Recursively mount / in private doort
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# note we'll remount /sys and /proc later
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errFail( 'mount -B / ' + self.root )
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self.mountDirs( self.remounts )
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self.mountPrivateDirs()
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def unmountBindMounts( self ):
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"Unmount all of our bind mounts"
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unmountAll( self.rundir )
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def popen( self, *args, **kwargs ):
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"Popen with chroot support"
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chroot = kwargs.pop( 'chroot', True )
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mncmd = kwargs.get( 'mncmd',
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[ 'mnexec', '-a', str( self.pid ) ] )
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if chroot:
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mncmd = [ 'chroot', self.root ] + mncmd
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kwargs[ 'mncmd' ] = mncmd
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return Host.popen( self, *args, **kwargs )
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def cleanup( self ):
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"""Clean up, then unmount bind mounts
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unmount: actually unmount bind mounts?"""
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# Wait for process to actually terminate
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self.shell.wait()
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Host.cleanup( self )
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if self.unmount:
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self.unmountBindMounts()
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errFail( 'rmdir ' + self.root )
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# Convenience aliases
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findRemounts = HostWithPrivateDirs.findRemounts
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# Sample usage
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def testHostWithPrivateDirs():
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"Test bind mounts"
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topo = SingleSwitchTopo( 10 )
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remounts = findRemounts( fstypes=[ 'nfs' ] )
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privateDirs = [ '/var/log', '/var/run' ]
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host = partial( HostWithPrivateDirs, remounts=remounts,
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privateDirs=privateDirs, unmount=False )
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privateDirs = [ ( '/var/log', '/tmp/%(name)s/var/log' ),
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( '/var/run', '/tmp/%(name)s/var/run' ),
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'/var/mn' ]
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host = partial( HostWithPrivateDirs,
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privateDirs=privateDirs )
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net = Mininet( topo=topo, host=host )
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net.start()
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info( 'Private Directories:', privateDirs, '\n' )
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directories = []
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for directory in privateDirs:
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directories.append( directory[ 0 ]
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if isinstance( directory, tuple )
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else directory )
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info( 'Private Directories:', directories, '\n' )
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CLI( net )
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net.stop()
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# We do this all at once to save a bit of time
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info( 'Unmounting host bind mounts...\n' )
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unmountAll()
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if __name__ == '__main__':
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unmountAll()
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setLogLevel( 'info' )
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testHostWithPrivateDirs()
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info( 'Done.\n')
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@@ -16,6 +16,11 @@ Host: a virtual host. By default, a host is simply a shell; commands
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CPULimitedHost: a virtual host whose CPU bandwidth is limited by
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RT or CFS bandwidth limiting.
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HostWithPrivateDirs: a virtual host that has user-specified private
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directories. These may be temporary directories stored as a tmpfs,
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or persistent directories that are mounted from another directory in
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the root filesystem.
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Switch: superclass for switch nodes.
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UserSwitch: a switch using the user-space switch from the OpenFlow
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@@ -725,6 +730,33 @@ class CPULimitedHost( Host ):
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mountCgroups()
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cls.inited = True
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class HostWithPrivateDirs( Host ):
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"Host with private directories"
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def __init__( self, name, *args, **kwargs ):
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"privateDirs: list of private directory strings or tuples"
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self.name = name
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self.privateDirs = kwargs.pop( 'privateDirs', [] )
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Host.__init__( self, name, *args, **kwargs )
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self.mountPrivateDirs()
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def mountPrivateDirs( self ):
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"mount private directories"
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for directory in self.privateDirs:
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if isinstance( directory, tuple ):
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# mount given private directory
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privateDir = directory[ 1 ] % self.__dict__
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mountPoint = directory[ 0 ]
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self.cmd( 'mkdir -p %s' % privateDir )
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self.cmd( 'mkdir -p %s' % mountPoint )
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self.cmd( 'mount --bind %s %s' %
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( privateDir, mountPoint ) )
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else:
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# mount temporary filesystem on directory
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self.cmd( 'mkdir -p %s' % directory )
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self.cmd( 'mount -n -t tmpfs tmpfs %s' % directory )
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# Some important things to note:
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#
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@@ -140,7 +140,7 @@ int main(int argc, char *argv[])
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fflush(stdout);
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break;
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case 'a':
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/* Attach to pid's network namespace */
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/* Attach to pid's network namespace and mount namespace*/
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pid = atoi(optarg);
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sprintf(path, "/proc/%d/ns/net", pid );
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nsid = open(path, O_RDONLY);
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@@ -152,6 +152,16 @@ int main(int argc, char *argv[])
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perror("setns");
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return 1;
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}
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sprintf(path, "/proc/%d/ns/mnt", pid );
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nsid = open(path, O_RDONLY);
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if (nsid < 0) {
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perror(path);
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return 1;
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}
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if (setns(nsid, 0) != 0) {
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perror("setns");
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return 1;
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}
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break;
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case 'g':
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/* Attach to cgroup */
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