#
# Example script for creating and building a new Linux guest OS for Xen.
+# It takes an optional parameter that specifies offsets to be added to the
+# ip address and root partition numbers, enabling multiple domains to be
+# started from the one script.
+#
+# Edit as required...
#
-import Xc, XenoUtil, sys, os
+import Xc, XenoUtil, string, sys, os, time, socket
-# Variable declaration. Set these up properly later on, as needed.
-nfsserv = nfspath = root_partn = usr_partn = ""
+# initialize a few variables that might come in handy
+thishostname = socket.gethostname()
+guestid = 0
+if sys.argv >= 2:
+ guestid = string.atoi(sys.argv[1])
+ print "Offset to add to guest's IP etc : %d\n" % guestid
+
+##### This section of the code establishes various settings to be used
+##### for this guest virtual machine
-# STEP 1. Specify kernel image file.
-image = "FULL_PATH_TO_IMAGE"
+# STEP 1. Specify kernel image file. Can be gzip'ed.
+image = "../../../install/boot/xenolinux.gz"
# STEP 2. How many megabytes of memory for the new domain?
memory_megabytes = 64
# STEP 3. A handy name for your new domain.
-domain_name = "My new domain"
+domain_name = "This is VM %d" % guestid
+
+# STEP 4. Specify IP address(es), netmask and gateway for the new
+# domain. You need to configure IP addrs within the domain just as
+# you do normally. This is just to let Xen know about them so it can
+# route packets appropriately.
-# STEP 4. Specify IP address, netmask and gateway for the new domain.
-ipaddr = "ADDRESS"
+#ipaddr = ["111.222.333.444","222.333.444.555"]
+ipaddr = [XenoUtil.add_offset_to_ip(XenoUtil.get_current_ipaddr(),guestid)]
netmask = XenoUtil.get_current_ipmask()
gateway = XenoUtil.get_current_ipgw()
+nfsserv = '169.254.1.0' # You need to set this if you're using NFS root
-# STEP 5a. Specify NFS server and path to rootfs (only needed for network boot)
-nfsserv = "ADDRESS"
-nfspath = "FULL_PATH_TO_ROOT_DIR"
-
-# STEP 5b. Specify root partition on local disc (if not NFS booting)
-#root_partn = "/dev/sda2"
-# (NB. The following is only needed for a separate shared read-only /usr)
-# (usr_partn = "/dev/sda6")
-
-# STEP 6. Check that the following cmdline setup is to your taste.
-cmdline = "ip="+ipaddr+":"+nfsserv+":"+gateway+":"+netmask+"::eth0:off"
-if root_partn:
- # Boot from local disc. May specify a separate /usr.
- cmdline = cmdline + " root="+root_partn+" ro"
- if usr_partn:
- " usr="+usr_partn
-elif nfsserv:
- # NFS boot
- cmdline = cmdline + " root=/dev/nfs"
- cmdline = cmdline + " nfsroot="+nfspath
-
-if root_partn:
- root_info = XenoUtil.lookup_blkdev_partn_info(root_partn)
- if not root_info:
- print "Could not obtain info on partition '" + root_partn + "'"
- sys.exit()
+# STEP 5. Identify any physcial partitions or virtual disks you want the
+# domain to have access to, and what you want them accessible as
+# e.g. vbds = [ ('phy:sda1','sda1', 'w'),
+# ('phy:sda4','sda%d' % (3+guestid), 'r'),
+# ('vd:as73gd784dh','hda1','w') ]
-if usr_partn:
- usr_info = XenoUtil.lookup_blkdev_partn_info(usr_partn)
- if not usr_info:
- print "Could not obtain info on partition '" + usr_partn + "'"
- sys.exit()
+vbds = [ ('phy:sda%d'%(7+guestid),'sda1','w' ),
+ ('phy:sda6','sda6','r'),
+ ('phy:cdrom','hdd','r') ]
-if not os.path.isfile( image ):
- print "Image file '" + image + "' does not exist"
- sys.exit()
+# STEP 6. Build the command line for the new domain. Edit as req'd.
+# You only need the ip= line if you're NFS booting or the root file system
+# doesn't set it later e.g. in ifcfg-eth0 or via DHCP
+# You can use 'extrabit' to set the runlevel and custom environment
+# variables used by custom rc scripts (e.g. DOMID=, usr= )
-xc = Xc.new()
+ipbit = "ip="+ipaddr[0]+":"+nfsserv+":"+gateway+":"+netmask+"::eth0:off"
+rootbit = "root=/dev/sda1 ro"
+#rootbit = "root=/dev/nfs nfsroot=/full/path/to/root/directory"
+extrabit = "4 DOMID=%d usr=/dev/sda6" % guestid
+cmdline = ipbit +" "+ rootbit +" "+ extrabit
-id = xc.domain_create( mem_kb=memory_megabytes*1024, name=domain_name )
-if id <= 0:
- print "Error creating domain"
- sys.exit()
+# STEP 7. Set according to whether you want the script to watch the domain
+# and auto-restart it should it die or exit.
-if xc.linux_build( dom=id, image=image, cmdline=cmdline ):
- print "Error building Linux guest OS"
- xc.domain_destroy ( dom=id )
- sys.exit()
+auto_restart = False
+#auto_restart = True
-if root_partn:
- if xc.vbd_create( dom=id, vbd=root_info[0], writeable=1 ):
- print "Error creating root VBD"
- xc.domain_destroy ( dom=id )
+
+##### Print some debug info just incase things don't work out...
+#####
+
+print "Domain image : ", image
+print "Domain memory : ", memory_megabytes
+print "Domain IP address(es) : ", ipaddr
+print "Domain block devices : ", vbds
+print 'Domain cmdline : "%s"' % cmdline
+
+
+##### Code beyond this point is actually used to manage the mechanics of
+##### starting (and watching if necessary) guest virtual machines.
+
+# Obtain an instance of the Xen control interface
+xc = Xc.new()
+
+# This function creates, builds and starts a domain, using the values
+# in the global variables, set above. It is used in the subsequent
+# code for starting the new domain and rebooting it if appropriate.
+def make_domain():
+ """Create, build and start a domain.
+ Returns: [int] the ID of the new domain.
+ """
+
+ # set up access to the global variables declared above
+ global image, memory_megabytes, domain_name, ipaddr, netmask
+ global vbds, cmdline, xc
+
+ if not os.path.isfile( image ):
+ print "Image file '" + image + "' does not exist"
sys.exit()
- if xc.vbd_grow( dom=id,
- vbd=root_info[0],
- device=root_info[1],
- start_sector=root_info[2],
- nr_sectors=root_info[3] ):
- print "Error populating root VBD"
- xc.domain_destroy ( dom=id )
+
+ id = xc.domain_create( mem_kb=memory_megabytes*1024, name=domain_name )
+ print "Created new domain with id = " + str(id)
+ if id <= 0:
+ print "Error creating domain"
sys.exit()
-if usr_partn:
- if xc.vbd_create( dom=id, vbd=usr_info[0], writeable=0 ):
- print "Error creating usr VBD"
+ ret = xc.linux_build( dom=id, image=image, cmdline=cmdline )
+ if ret < 0:
+ print "Error building Linux guest OS: "
+ print "Return code from linux_build = " + str(ret)
xc.domain_destroy ( dom=id )
sys.exit()
- if xc.vbd_grow( dom=id,
- vbd=usr_info[0],
- device=usr_info[1],
- start_sector=usr_info[2],
- nr_sectors=usr_info[3] ):
- print "Error populating usr VBD"
+
+ # setup the virtual block devices
+ for ( uname, virt_name, rw ) in vbds:
+ virt_dev = XenoUtil.blkdev_name_to_number( virt_name )
+
+ segments = XenoUtil.lookup_disk_uname( uname )
+ if not segments:
+ print "Error looking up %s\n" % uname
+ xc.domain_destroy ( dom=id )
+ sys.exit()
+
+ if xc.vbd_create( dom=id, vbd=virt_dev, writeable= rw=='w' ):
+ print "Error creating VBD vbd=%d writeable=%d\n" % (virt_dev,rw)
+ xc.domain_destroy ( dom=id )
+ sys.exit()
+
+ for (s_dev,s_start,s_len,s_type) in segments:
+ if xc.vbd_grow( dom=id,
+ vbd=virt_dev,
+ device=s_dev,
+ start_sector=s_start,
+ nr_sectors=s_len ):
+ print "Error populating VBD vbd=%d\n" % virt_dev
+ xc.domain_destroy ( dom=id )
+ sys.exit()
+
+ # setup virtual firewall rules for all aliases
+ for ip in ipaddr:
+ XenoUtil.setup_vfr_rules_for_vif( id, 0, ip )
+
+ if xc.domain_start( dom=id ) < 0:
+ print "Error starting domain"
xc.domain_destroy ( dom=id )
sys.exit()
-XenoUtil.setup_vfr_rules_for_vif( id, 0, ipaddr )
+ return id
+# end of make_domain()
+
+
+
+# The starting / monitoring of the domain actually happens here...
+
+# start the domain and record its ID number
+current_id = make_domain()
+
+# if the auto_restart flag is set then keep polling to see if the domain is
+# alive - restart if it is not by calling make_domain() again (it's necessary
+# to update the id variable, since the new domain may have a new ID)
-if xc.domain_start( dom=id ):
- print "Error starting domain"
- xc.domain_destroy ( dom=id )
- sys.exit()
+while auto_restart:
+ time.sleep(1)
+ if not xc.domain_getinfo(current_id):
+ print "The virtual machine has terminated, restarting in a new domain"
+ current_id = make_domain()
+++ /dev/null
-#!/usr/bin/env python
-
-# Example script for creating and building a new Linux guest OS for
-# Xen. THIS IS VERY SITE SPECIFIC, but shows an example configuration
-# using multiple root partitions with a common /usr. e.g. Domain1
-# uses root /dev/sda8, usr /dev/sda6, and the next sequential IP address.
-
-import Xc, XenoUtil, sys, os, socket, re
-
-# Variable declaration. Set these up properly later on, as needed.
-nfsserv = nfspath = root_partn = usr_partn = ""
-shost = re.search( '([a-zA-Z]+)[-.]', socket.gethostname() ).group(1)
-
-# STEP 1. Specify kernel image file.
-image = "/usr/groups/srgboot/%s/xenolinux.gz" % shost
-
-# STEP 2. How many megabytes of memory for the new domain?
-memory_megabytes = 64
-
-# STEP 3. A handy name for your new domain.
-domain_name = "My new domain"
-
-# Allocate new domain ad get its domain id
-xc = Xc.new()
-id = xc.domain_create( mem_kb=memory_megabytes*1024, name=domain_name )
-if id <= 0:
- print "Error creating domain"
- sys.exit()
-
-# Set the CPU, or leave to round robin allocation
-#xc.domain_pincpu( dom=id, cpu=1 )
-
-# STEP 4. Specify IP address, netmask and gateway for the new domain.
-ipaddr = XenoUtil.add_offset_to_ip(XenoUtil.get_current_ipaddr(),id)
-netmask = XenoUtil.get_current_ipmask()
-gateway = XenoUtil.get_current_ipgw()
-
-# STEP 5a. Specify NFS server and path to rootfs (only needed for network boot)
-#nfsserv = "ADDRESS"
-#nfspath = "FULL_PATH_TO_ROOT_DIR"
-
-# STEP 5b. Specify root partition on local disc (if not NFS booting)
-root_partn = "/dev/sda%d" % (7+id)
-# (NB. The following is only needed for a separate shared read-only /usr)
-usr_partn = "/dev/sda6"
-
-# STEP 6. Check that the following cmdline setup is to your taste.
-cmdline = "ip="+ipaddr+":"+nfsserv+":"+gateway+":"+netmask+"::eth0:off"
-if root_partn:
- # Boot from local disc. May specify a separate /usr.
- cmdline = cmdline + " root="+root_partn+" ro"
- if usr_partn:
- " usr="+usr_partn
-elif nfsserv:
- # NFS boot
- cmdline = cmdline + " root=/dev/nfs"
- cmdline = cmdline + " nfsroot="+nfspath
-
-if root_partn:
- root_info = XenoUtil.lookup_blkdev_partn_info(root_partn)
- if not root_info:
- print "Could not obtain info on partition '" + root_partn + "'"
- sys.exit()
-
-if usr_partn:
- usr_info = XenoUtil.lookup_blkdev_partn_info(usr_partn)
- if not usr_info:
- print "Could not obtain info on partition '" + usr_partn + "'"
- sys.exit()
-
-if not os.path.isfile( image ):
- print "Image file '" + image + "' does not exist"
- sys.exit()
-
-
-if xc.linux_build( dom=id, image=image, cmdline=cmdline ):
- print "Error building Linux guest OS"
- xc.domain_destroy ( dom=id )
- sys.exit()
-
-if root_partn:
- if xc.vbd_create( dom=id, vbd=root_info[0], writeable=1 ):
- print "Error creating root VBD"
- xc.domain_destroy ( dom=id )
- sys.exit()
- if xc.vbd_grow( dom=id,
- vbd=root_info[0],
- device=root_info[1],
- start_sector=root_info[2],
- nr_sectors=root_info[3] ):
- print "Error populating root VBD"
- xc.domain_destroy ( dom=id )
- sys.exit()
-
-if usr_partn:
- if xc.vbd_create( dom=id, vbd=usr_info[0], writeable=0 ):
- print "Error creating usr VBD"
- xc.domain_destroy ( dom=id )
- sys.exit()
- if xc.vbd_grow( dom=id,
- vbd=usr_info[0],
- device=usr_info[1],
- start_sector=usr_info[2],
- nr_sectors=usr_info[3] ):
- print "Error populating usr VBD"
- xc.domain_destroy ( dom=id )
- sys.exit()
-
-XenoUtil.setup_vfr_rules_for_vif( id, 0, ipaddr )
-
-if xc.domain_start( dom=id ):
- print "Error starting domain"
- xc.domain_destroy ( dom=id )
- sys.exit()
projects / xen.git / commitdiff