On Sun, Feb 08, 2004 at 09:19:56AM +0000, Ian Pratt wrote:
> Of course, this will all be much neater in rev 3 of the domain
> control tools that will use a db backend to maintain state about
> currently running domains across a cluster...
Ack! We might be doing duplicate work. How far have you gotten with
this?
Right now I'm running python code (distantly descended from
createlinuxdom.py) that is able to:
- monitor each domain and restart as needed
- migrate domains from one host to another
- dynamically create and assign swap vd's, and garbage collect them at
shutdown or after crash
...and a few other things. Right now migration is via reboot, not
suspend; haven't had a chance to troubleshoot resume further.
The only thing I'm using VD's for at this point is swap. This code so
far depends on NFS root partitions, all served from a central NFS
server; control and state are communicated via NFS also. I just today
started migrating the control/state comms to jabber instead, so that I
could start using VD root filesystems after the COW stuff settles down.
Haven't decided what to do for migrating filesystems between nodes in
that case though.
Right now I'm calling this 'txenmon' (TerraLuna Xen Monitor) but was
already considering renaming it 'xenmon' and posting it after I got it
cleaned up.
This is all to support a production Xen cluster rollout that I plan to
have running by the end of this month. I really don't want to go back
to UML at this point, and if I don't have this cluster running by March
I'm in deep doo-doo -- so I'm committed to working full-time on Xen
tools now. ;-}
So here's the current version, not cleaned up, way too verbose, crufty,
but running:
Steve
#!/usr/bin/python2.2
import Xc, XenoUtil, string, sys, os, time, socket, cPickle
# initialize a few variables that might come in handy
thishostname = socket.gethostname()
if not len(sys.argv) >= 2:
print "usage: %s /path/to/base/of/users/hosts" % sys.argv[0]
sys.exit(1)
nfsserv="10.27.2.50"
base = sys.argv[1]
if len(base) > 1 and base.endswith('/'):
base=base[:-1]
# Obtain an instance of the Xen control interface
xc = Xc.new()
# daemonize
daemonize=0
if daemonize:
try:
pid = os.fork()
if pid > 0:
# exit first parent
sys.exit(0)
except OSError, e:
print >>sys.stderr, "fork #1 failed: %d (%s)" % (e.errno, e.strerror)
sys.exit(1)
# decouple from parent environment
# os.chdir("/")
os.setsid()
os.umask(0)
# XXX what about stdout etc?
# do second fork
try:
pid = os.fork()
if pid > 0:
# exit from second parent, print eventual PID before
# print "Daemon PID %d" % pid
sys.exit(0)
except OSError, e:
print >>sys.stderr, "fork #2 failed: %d (%s)" % (e.errno, e.strerror)
sys.exit(1)
def main():
while 1:
guests=getGuests(base)
# state machine
for guest in guests:
print guest.path,guest.activeHost,guest.isRunning()
if guest.isMine():
if guest.isRunningHere():
guest.heartbeat()
if guest.isRunnable():
if guest.isRunningHere():
pass
else:
if guest.isRunning():
print "warning: %s is running on %s" % (
guest.name, guest.activeHost
)
else:
guest.start()
else: # not guest.isRunnable()
if guest.isRunningHere():
guest.shutdown()
if guest.isHung():
guest.destroy()
else: # not guest.isMine()
if guest.isRunningHere():
guest.shutdown()
if guest.isRunning():
pass
else:
print "warning: %s is not running on %s" % (
guest.name,guest.ctl('host')
)
# end state machine
# garbage collect vd's
usedVds=[]
for guest in guests:
if guest.isRunningHere():
usedVds+=guest.vds()
guest.pickle()
for vd in listvdids():
print "usedVds =",usedVds
if vd in usedVds:
pass
else:
print "deleting vd %s" % vd
XenoUtil.vd_delete(vd)
# garbage collect domains
# XXX
time.sleep(10)
# end while
def getGuests(base):
users=os.listdir(base)
guests=[]
for user in users:
if not os.path.isdir("%s/%s" % (base,user)):
continue
guestnames=os.listdir("%s/%s" % (base,user))
for name in guestnames:
path="%s/%s/%s" % (base,user,name)
try:
try:
file=open("%s/log/pickle" % path,"r")
guest=cPickle.load(file)
file.close()
except:
print "creating",path
guest=Guest(path)
except:
print "exception creating guest %s/%s: %s" % (
user,
name,
sys.exc_info()[1].__dict__
)
continue
guests.append(guest)
return guests
def listvdids():
vdids=[]
for vbd in XenoUtil.vd_list():
vdids.append(vbd['vdisk_id'])
print "listvdids =", vdids
return vdids
class Guest(object):
def __init__(self,path):
self.reload(path)
def reload(self,path):
pathparts=path.split('/')
name=pathparts.pop()
user=pathparts.pop()
base='/'.join(pathparts)
self.path=path
self.base=base
self.user=user
self.name=name
self.domain_name="%s" % name
self.ctlcache={}
# requested domain id number
self.domid=self.ctl("domid")
# kernel
self.image=self.ctl("kernel")
# memory
self.memory_megabytes=int(self.ctl("mem"))
swap=self.ctl("swap")
(swap_dev,swap_megabytes) = swap.split(",")
self.swap_dev=swap_dev
self.swap_megabytes=int(swap_megabytes)
# ip
self.ipaddr = [self.ctl("ip")]
self.netmask = XenoUtil.get_current_ipmask()
self.gateway = self.ctl("gw")
# vbd's
vbds = []
vbdfile = open("%s/ctl/vbds" % self.path,"r")
for line in vbdfile.readlines():
print line
( uname, virt_name, rw ) = line.split(',')
uname = uname.strip()
virt_name = virt_name.strip()
rw = rw.strip()
vbds.append(( uname, virt_name, rw ))
self.vbds=vbds
self.vbd_expert = 0
# build kernel command line
ipbit = "ip="+self.ipaddr[0]
ipbit += ":"+nfsserv
ipbit += ":"+self.gateway+":"+self.netmask+"::eth0:off"
rootbit = "root=/dev/nfs nfsroot=/export/%s/root" % path
extrabit = "4 DOMID=%s " % self.domid
self.cmdline = ipbit +" "+ rootbit +" "+ extrabit
self.curid=None
self.swapvdid=None
self.shutdownTime=None
self.activeHost=None
def ctl(self,var):
filename="%s/ctl/%s" % (self.path,var)
# if not hasattr(self,'ctlcache'):
# print dir(self)
# print self.path
# self.ctlcache={}
if not self.ctlcache.has_key('filename'):
self.ctlcache[filename]={'mtime': 0, 'val': None}
val=None
mtime=os.path.getmtime(filename)
if self.ctlcache[filename]['mtime'] < mtime:
val = open(filename,"r").readline().strip()
self.ctlcache[filename]={'mtime': mtime, 'val': val}
else:
val = self.ctlcache[filename]['val']
return val
def destroy(self):
print "destroying %s" % self.domain_name
# print "now curid =",self.curid
if self.curid == 0:
raise "attempt to kill dom0"
xc.domain_destroy(dom=self.curid,force=True)
def heartbeat(self):
assert self.isRunningHere()
# update swap expiry to one day
try:
XenoUtil.vd_refresh(self.swapvdid, 86400)
except:
print "%s missed swap expiry update: %s" % (
self.domain_name,
sys.exc_info()[1].__dict__
)
self.activeHost=thishostname
self.pickle()
def isHung(self):
if not self.isRunningHere():
return False
if self.shutdownTime and time.time() - self.shutdownTime > 300:
return True
return False
def isMine(self):
if self.ctl("host") == thishostname:
return True
return False
def isRunnable(self):
run=int(self.ctl("run"))
if run > 0:
return True
return False
def isRunning(self):
if self.isRunningHere():
return True
else:
host=self.activeHost
if host == None:
return None
if host == thishostname:
return False
filename="%s/log/%s" % (self.path,"pickle")
mtime=None
try:
mtime=os.path.getmtime(filename)
except:
return False
now=time.time()
if now - mtime < 60:
return True
return False
def isRunningHere(self):
if not self.curid or self.curid == 0:
return False
domains=xc.domain_getinfo()
domids = [ d['dom'] for d in domains ]
if self.curid in domids:
# print self.curid
return True
self.curid=None
return False
def XXXlog(self,var,val=None,append=False):
filename="%s/log/%s" % (self.path,var)
if val==None:
out=None
try:
out=open(filename,"r").readlines()
except:
return None
out=[l.strip() for l in out]
return out
mode="w"
if append:
mode="a"
file=open(filename,mode)
file.write("%s\n" % str(val))
file.close()
def mkswap(self):
# create swap, 1 minute expiry
vdid=XenoUtil.vd_create(self.swap_megabytes,60)
# print "vdid =",vdid
self.swapvdid=vdid
uname="vd:%s" % vdid
# format it
segments = XenoUtil.lookup_disk_uname(uname)
if XenoUtil.vd_extents_validate(segments,1) < 0:
print "segment conflict on %s" % uname
sys.exit(1)
tmpdev="/dev/xenswap%s" % vdid
cmd="mknod %s b 125 %s" % (tmpdev,vdid)
os.system(cmd)
virt_dev = XenoUtil.blkdev_name_to_number(tmpdev)
xc.vbd_create(0,virt_dev,1)
xc.vbd_setextents(0,virt_dev,segments)
cmd="mkswap %s" % tmpdev
os.system(cmd)
xc.vbd_destroy(0,virt_dev)
self.vbds.append(( uname, self.swap_dev, "w" ))
print "mkswap:",uname, self.swap_dev, "w"
print self.vbds
def pickle(self):
assert self.isRunningHere()
# write then rename so others see an atomic operation...
file=open("%s/log/pickle.new" % self.path,"w")
cPickle.dump(self,file)
file.close()
os.rename(
"%s/log/pickle.new" % self.path,
"%s/log/pickle" % self.path
)
def shutdown(self):
print "shutting down %s" % self.name
# reduce swap expiry to 10 minutes (to give it time to shut down)
if self.swapvdid:
XenoUtil.vd_refresh(self.swapvdid, 600)
xc.domain_destroy(dom=self.curid)
if not self.shutdownTime:
self.shutdownTime=time.time()
def start(self):
"""Create, build and start the domain for this guest."""
self.reload(self.path)
image=self.image
memory_megabytes=self.memory_megabytes
domain_name=self.domain_name
ipaddr=self.ipaddr
netmask=self.netmask
vbds=self.vbds
cmdline=self.cmdline
vbd_expert=self.vbd_expert
print "Domain image : ", self.image
print "Domain memory : ", self.memory_megabytes
print "Domain IP address(es) : ", self.ipaddr
print "Domain block devices : ", self.vbds
print 'Domain cmdline : "%s"' % self.cmdline
if self.isRunning():
raise "%s already running on %s" % (self.name,self.activeHost)
if not os.path.isfile( image ):
print "Image file '" + image + "' does not exist"
return None
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"
return None
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 )
return None
# setup the virtual block devices
# set the expertise level appropriately
XenoUtil.VBD_EXPERT_MODE = vbd_expert
self.mkswap()
self.datavds=[]
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 or segments < 0:
print "Error looking up %s\n" % uname
xc.domain_destroy ( dom=id )
return None
# check that setting up this VBD won't violate the sharing
# allowed by the current VBD expertise level
# print uname, virt_name, rw, segments
if XenoUtil.vd_extents_validate(segments, rw=='w' or rw=='rw') < 0:
xc.domain_destroy( dom = id )
return None
if xc.vbd_create( dom=id, vbd=virt_dev, writeable= rw=='w' or
rw=='rw' ):
print "Error creating VBD vbd=%d writeable=%d\n" % (virt_dev,rw)
xc.domain_destroy ( dom=id )
return None
if xc.vbd_setextents(
dom=id,
vbd=virt_dev,
extents=segments):
print "Error populating VBD vbd=%d\n" % virt_dev
xc.domain_destroy ( dom=id )
return None
self.datavds.append(virt_dev)
# 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()
self.curid=id
print "domain (re)started: %s (%d)" % (domain_name,id)
self.heartbeat()
return id
def vds(self):
vds=[]
# XXX add data vbds
vds.append(self.swapvdid)
return vds
main()
--
Stephen G. Traugott (KG6HDQ)
UNIX/Linux Infrastructure Architect, TerraLuna LLC
stevegt@xxxxxxxxxxxxx
http://www.stevegt.com -- http://Infrastructures.Org
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