python/vserver.py

   1 # Copyright 2005 Princeton University
   2
   3 #$Id: vserver.py,v 1.66 2007/07/31 16:31:04 dhozac Exp $
   4
   5 import errno
   6 import fcntl
   7 import os
   8 import re
   9 import pwd
  10 import signal
  11 import sys
  12 import time
  13 import traceback
  14 import subprocess
  15 import resource
  16
  17 import mountimpl
  18 import runcmd
  19 import utmp
  20 import vserverimpl
  21 import cpulimit, bwlimit
  22
  23 from vserverimpl import VS_SCHED_CPU_GUARANTEED as SCHED_CPU_GUARANTEED
  24 from vserverimpl import DLIMIT_INF
  25 from vserverimpl import VC_LIM_KEEP
  26 from vserverimpl import VLIMIT_NSOCK
  27 from vserverimpl import VLIMIT_OPENFD
  28 from vserverimpl import VLIMIT_ANON
  29 from vserverimpl import VLIMIT_SHMEM
  30
  31 #
  32 # these are the flags taken from the kernel linux/vserver/legacy.h
  33 #
  34 FLAGS_LOCK = 1
  35 FLAGS_SCHED = 2  # XXX - defined in util-vserver/src/chcontext.c
  36 FLAGS_NPROC = 4
  37 FLAGS_PRIVATE = 8
  38 FLAGS_INIT = 16
  39 FLAGS_HIDEINFO = 32
  40 FLAGS_ULIMIT = 64
  41 FLAGS_NAMESPACE = 128
  42
  43 RLIMITS = { "NSOCK": VLIMIT_NSOCK,
  44             "OPENFD": VLIMIT_OPENFD,
  45             "ANON": VLIMIT_ANON,
  46             "SHMEM": VLIMIT_SHMEM}
  47
  48 # add in the platform supported rlimits
  49 for entry in resource.__dict__.keys():
  50     if entry.find("RLIMIT_")==0:
  51         k = entry[len("RLIMIT_"):]
  52         if not RLIMITS.has_key(k):
  53             RLIMITS[k]=resource.__dict__[entry]
  54         else:
  55             print "WARNING: duplicate RLIMITS key %s" % k
  56
  57 class NoSuchVServer(Exception): pass
  58
  59
  60 class VServerConfig:
  61     def __init__(self, name, directory):
  62         self.name = name
  63         self.dir = directory
  64
  65     def get(self, option, default = None):
  66         try:
  67             f = open(os.path.join(self.dir, option), "r")
  68             buf = f.readline().rstrip()
  69             f.close()
  70             return buf
  71         except IOError, e:
  72             if default is not None:
  73                 return default
  74             else:
  75                 raise KeyError, "Key %s is not set for %s" % (option, self.name)
  76
  77     def update(self, option, value):
  78         try:
  79             old_umask = os.umask(0022)
  80             filename = os.path.join(self.dir, option)
  81             try:
  82                 os.makedirs(os.path.dirname(filename), 0755)
  83             except:
  84                 pass
  85             f = open(filename, 'w')
  86             if isinstance(value, list):
  87                 f.write("%s\n" % "\n".join(value))
  88             else:
  89                 f.write("%s\n" % value)
  90             f.close()
  91             os.umask(old_umask)
  92         except:
  93             raise
  94
  95     def unset(self, option):
  96         try:
  97             filename = os.path.join(self.dir, option)
  98             os.unlink(filename)
  99             os.removedirs(os.path.dirname(filename))
 100             return True
 101         except:
 102             return False
 103
 104
 105 class VServer:
 106
 107     INITSCRIPTS = [('/etc/rc.vinit', 'start'),
 108                    ('/etc/rc.d/rc', '%(runlevel)d')]
 109
 110     def __init__(self, name, vm_id = None, vm_running = None):
 111
 112         self.name = name
 113         self.rlimits_changed = False
 114         self.dir = "%s/%s" % (vserverimpl.VSERVER_BASEDIR, name)
 115         if not (os.path.isdir(self.dir) and
 116                 os.access(self.dir, os.R_OK | os.W_OK | os.X_OK)):
 117             raise NoSuchVServer, "no such vserver: " + name
 118         self.config = VServerConfig(name, "/etc/vservers/%s" % name)
 119         self.remove_caps = ~vserverimpl.CAP_SAFE;
 120         if vm_id == None:
 121             vm_id = int(self.config.get('context'))
 122         self.ctx = vm_id
 123         if vm_running == None:
 124             vm_running = self.is_running()
 125         self.vm_running = vm_running
 126
 127     def have_limits_changed(self):
 128         return self.rlimits_changed
 129
 130     def set_rlimit_limit(self,type,hard,soft,minimum):
 131         """Generic set resource limit function for vserver"""
 132         global RLIMITS
 133         changed = False
 134         try:
 135             old_hard, old_soft, old_minimum = self.get_rlimit_limit(type)
 136             if old_hard != VC_LIM_KEEP and old_hard <> hard: changed = True
 137             if old_soft != VC_LIM_KEEP and old_soft <> soft: changed = True
 138             if old_minimum != VC_LIM_KEEP and old_minimum <> minimum: changed = True
 139             self.rlimits_changed = self.rlimits_changed or changed
 140         except OSError, e:
 141             if self.is_running(): print "Unexpected error with getrlimit for running context %d" % self.ctx
 142
 143         resource_type = RLIMITS[type]
 144         try:
 145             ret = vserverimpl.setrlimit(self.ctx,resource_type,hard,soft,minimum)
 146         except OSError, e:
 147             if self.is_running(): print "Unexpected error with setrlimit for running context %d" % self.ctx
 148
 149     def set_rlimit_config(self,type,hard,soft,minimum):
 150         """Generic set resource limit function for vserver"""
 151         if hard <> VC_LIM_KEEP:
 152             self.config.update('rlimits/%s.hard' % type.lower(), hard)
 153         if soft <> VC_LIM_KEEP:
 154             self.config.update('rlimits/%s.soft' % type.lower(), soft)
 155         if minimum <> VC_LIM_KEEP:
 156             self.config.update('rlimits/%s.min' % type.lower(), minimum)
 157         self.set_rlimit_limit(type,hard,soft,minimum)
 158
 159     def get_rlimit_limit(self,type):
 160         """Generic get resource configuration function for vserver"""
 161         global RLIMITS
 162         resource_type = RLIMITS[type]
 163         try:
 164             ret = vserverimpl.getrlimit(self.ctx,resource_type)
 165         except OSError, e:
 166             print "Unexpected error with getrlimit for context %d" % self.ctx
 167             ret = self.get_rlimit_config(type)
 168         return ret
 169
 170     def get_rlimit_config(self,type):
 171         """Generic get resource configuration function for vserver"""
 172         hard = int(self.config.get("rlimits/%s.hard"%type.lower(),VC_LIM_KEEP))
 173         soft = int(self.config.get("rlimits/%s.soft"%type.lower(),VC_LIM_KEEP))
 174         minimum = int(self.config.get("rlimits/%s.min"%type.lower(),VC_LIM_KEEP))
 175         return (hard,soft,minimum)
 176
 177     def set_WHITELISTED_config(self,whitelisted):
 178         self.config.update('whitelisted', whitelisted)
 179
 180     def set_capabilities(self, capabilities):
 181         return vserverimpl.setbcaps(self.ctx, vserverimpl.text2bcaps(capabilities))
 182
 183     def set_capabilities_config(self, capabilities):
 184         self.config.update('bcapabilities', capabilities)
 185         self.set_capabilities(capabilities)
 186
 187     def get_capabilities(self):
 188         return vserverimpl.bcaps2text(vserverimpl.getbcaps(self.ctx))
 189
 190     def get_capabilities_config(self):
 191         return self.config.get('bcapabilities', '')
 192
 193     def set_ipaddresses(self, addresses):
 194         vserverimpl.netremove(self.ctx, "all")
 195         for a in addresses.split(","):
 196             vserverimpl.netadd(self.ctx, a)
 197
 198     def set_ipaddresses_config(self, addresses):
 199         i = 0
 200         for a in addresses.split(","):
 201             self.config.update("interfaces/%d/ip" % i, a)
 202             i += 1
 203         while self.config.unset("interfaces/%d/ip" % i):
 204             i += 1
 205         self.set_ipaddresses(addresses)
 206
 207     def get_ipaddresses_config(self):
 208         i = 0
 209         ret = []
 210         while True:
 211             r = self.config.get("interfaces/%d/ip" % i, '')
 212             if r == '':
 213                 break
 214             ret += [r]
 215             i += 1
 216         return ",".join(ret)
 217
 218     def get_ipaddresses(self):
 219         # No clean way to do this right now.
 220         return None
 221
 222     def __do_chroot(self):
 223
 224         os.chroot(self.dir)
 225         os.chdir("/")
 226
 227     def chroot_call(self, fn, *args):
 228
 229         cwd_fd = os.open(".", os.O_RDONLY)
 230         try:
 231             root_fd = os.open("/", os.O_RDONLY)
 232             try:
 233                 self.__do_chroot()
 234                 result = fn(*args)
 235             finally:
 236                 os.fchdir(root_fd)
 237                 os.chroot(".")
 238                 os.fchdir(cwd_fd)
 239                 os.close(root_fd)
 240         finally:
 241             os.close(cwd_fd)
 242         return result
 243
 244     def set_disklimit(self, block_limit):
 245         # block_limit is in kB
 246         if block_limit == 0:
 247             try:
 248                 vserverimpl.unsetdlimit(self.dir, self.ctx)
 249             except OSError, e:
 250                 print "Unexpected error with unsetdlimit for context %d" % self.ctx
 251             return
 252
 253         if self.vm_running:
 254             block_usage = vserverimpl.DLIMIT_KEEP
 255             inode_usage = vserverimpl.DLIMIT_KEEP
 256         else:
 257             # init_disk_info() must have been called to get usage values
 258             block_usage = self.disk_blocks
 259             inode_usage = self.disk_inodes
 260
 261
 262         try:
 263             vserverimpl.setdlimit(self.dir,
 264                                   self.ctx,
 265                                   block_usage,
 266                                   block_limit,
 267                                   inode_usage,
 268                                   vserverimpl.DLIMIT_INF,  # inode limit
 269                                   2)   # %age reserved for root
 270         except OSError, e:
 271             print "Unexpected error with setdlimit for context %d" % self.ctx
 272
 273
 274         self.config.update('dlimits/0/space_total', block_limit)
 275
 276     def is_running(self):
 277         return vserverimpl.isrunning(self.ctx)
 278
 279     def get_disklimit(self):
 280
 281         try:
 282             (self.disk_blocks, block_limit, self.disk_inodes, inode_limit,
 283              reserved) = vserverimpl.getdlimit(self.dir, self.ctx)
 284         except OSError, ex:
 285             if ex.errno != errno.ESRCH:
 286                 raise
 287             # get here if no vserver disk limit has been set for xid
 288             block_limit = -1
 289
 290         return block_limit
 291
 292     def set_sched_config(self, cpu_share, sched_flags):
 293
 294         """ Write current CPU scheduler parameters to the vserver
 295         configuration file. This method does not modify the kernel CPU
 296         scheduling parameters for this context. """
 297
 298         if sched_flags & SCHED_CPU_GUARANTEED:
 299             cpu_guaranteed = cpu_share
 300         else:
 301             cpu_guaranteed = 0
 302         self.config.update('sched/fill-rate2', cpu_share)
 303         self.config.update('sched/fill-rate', cpu_guaranteed)
 304
 305         if self.vm_running:
 306             self.set_sched(cpu_share, sched_flags)
 307
 308     def set_sched(self, cpu_share, sched_flags = 0):
 309         """ Update kernel CPU scheduling parameters for this context. """
 310         vserverimpl.setsched(self.ctx, cpu_share, sched_flags)
 311
 312     def get_sched(self):
 313         # have no way of querying scheduler right now on a per vserver basis
 314         return (-1, False)
 315
 316     def set_bwlimit(self, minrate = bwlimit.bwmin, maxrate = None,
 317                     exempt_min = None, exempt_max = None,
 318                     share = None, dev = "eth0"):
 319
 320         if minrate is None:
 321             bwlimit.off(self.ctx, dev)
 322         else:
 323             bwlimit.on(self.ctx, dev, share,
 324                        minrate, maxrate, exempt_min, exempt_max)
 325
 326     def get_bwlimit(self, dev = "eth0"):
 327
 328         result = bwlimit.get(self.ctx)
 329         # result of bwlimit.get is (ctx, share, minrate, maxrate)
 330         if result:
 331             result = result[1:]
 332         return result
 333
 334     def open(self, filename, mode = "r", bufsize = -1):
 335
 336         return self.chroot_call(open, filename, mode, bufsize)
 337
 338     def __do_chcontext(self, state_file):
 339
 340         if state_file:
 341             print >>state_file, "%u" % self.ctx
 342             state_file.close()
 343
 344         if vserverimpl.chcontext(self.ctx, vserverimpl.text2bcaps(self.get_capabilities_config())):
 345             self.set_resources()
 346             vserverimpl.setup_done(self.ctx)
 347
 348     def __prep(self, runlevel, log):
 349
 350         """ Perform all the crap that the vserver script does before
 351         actually executing the startup scripts. """
 352
 353         # remove /var/run and /var/lock/subsys files
 354         # but don't remove utmp from the top-level /var/run
 355         RUNDIR = "/var/run"
 356         LOCKDIR = "/var/lock/subsys"
 357         filter_fn = lambda fs: filter(lambda f: f != 'utmp', fs)
 358         garbage = reduce((lambda (out, ff), (dir, subdirs, files):
 359                           (out + map((dir + "/").__add__, ff(files)),
 360                            lambda fs: fs)),
 361                          list(os.walk(RUNDIR)),
 362                          ([], filter_fn))[0]
 363         garbage += filter(os.path.isfile, map((LOCKDIR + "/").__add__,
 364                                               os.listdir(LOCKDIR)))
 365         if False:
 366             for f in garbage:
 367                 os.unlink(f)
 368
 369         # set the initial runlevel
 370         f = open(RUNDIR + "/utmp", "w")
 371         utmp.set_runlevel(f, runlevel)
 372         f.close()
 373
 374         # mount /proc and /dev/pts
 375         self.__do_mount("none", "/proc", "proc")
 376         # XXX - magic mount options
 377         self.__do_mount("none", "/dev/pts", "devpts", 0, "gid=5,mode=0620")
 378
 379     def __do_mount(self, *mount_args):
 380
 381         try:
 382             mountimpl.mount(*mount_args)
 383         except OSError, ex:
 384             if ex.errno == errno.EBUSY:
 385                 # assume already mounted
 386                 return
 387             raise ex
 388
 389     def enter(self):
 390         self.__do_chroot()
 391         self.__do_chcontext(None)
 392
 393     def start(self, wait, runlevel = 3):
 394         self.vm_running = True
 395         self.rlimits_changed = False
 396
 397         child_pid = os.fork()
 398         if child_pid == 0:
 399             # child process
 400             try:
 401                 # get a new session
 402                 os.setsid()
 403
 404                 # open state file to record vserver info
 405                 state_file = open("/var/run/vservers/%s" % self.name, "w")
 406
 407                 # use /dev/null for stdin, /var/log/boot.log for stdout/err
 408                 fd = os.open("/dev/null", os.O_RDONLY)
 409                 if fd != 0:
 410                     os.dup2(fd, 0)
 411                     os.close(fd)
 412                 self.__do_chroot()
 413                 log = open("/var/log/boot.log", "w", 0)
 414                 if log.fileno() != 1:
 415                     os.dup2(log.fileno(), 1)
 416                 os.dup2(1, 2)
 417
 418                 print >>log, ("%s: starting the virtual server %s" %
 419                               (time.asctime(time.gmtime()), self.name))
 420
 421                 # perform pre-init cleanup
 422                 self.__prep(runlevel, log)
 423
 424                 # execute each init script in turn
 425                 # XXX - we don't support all scripts that vserver script does
 426                 self.__do_chcontext(state_file)
 427                 for cmd in self.INITSCRIPTS + [None]:
 428                      try:
 429                          # enter vserver context
 430                          arg_subst = { 'runlevel': runlevel }
 431                          cmd_args = [cmd[0]] + map(lambda x: x % arg_subst,
 432                                                    cmd[1:])
 433                          print >>log, "executing '%s'" % " ".join(cmd_args)
 434                          os.spawnvp(os.P_WAIT,cmd[0],*cmd_args)
 435                      except:
 436                          traceback.print_exc()
 437                          os._exit(1)
 438
 439             # we get here due to an exception in the top-level child process
 440             except Exception, ex:
 441                 traceback.print_exc()
 442             os._exit(0)
 443
 444         # parent process
 445         return child_pid
 446
 447     def set_resources(self):
 448
 449         """ Called when vserver context is entered for first time,
 450         should be overridden by subclass. """
 451
 452         pass
 453
 454     def init_disk_info(self):
 455         cmd = "/usr/sbin/vdu --script --space --inodes --blocksize 1024 --xid %d %s" % (self.ctx, self.dir)
 456         p = subprocess.Popen(cmd, shell=True, stdin=subprocess.PIPE,
 457                              stdout=subprocess.PIPE, stderr=subprocess.PIPE,
 458                              close_fds=True)
 459         p.stdin.close()
 460         line = p.stdout.readline()
 461         if not line:
 462             sys.stderr.write(p.stderr.read())
 463         p.stdout.close()
 464         p.stderr.close()
 465         ret = p.wait()
 466
 467         (space, inodes) = line.split()
 468         self.disk_inodes = int(inodes)
 469         self.disk_blocks = int(space)
 470         #(self.disk_inodes, self.disk_blocks) = vduimpl.vdu(self.dir)
 471
 472         return self.disk_blocks * 1024
 473
 474     def stop(self, signal = signal.SIGKILL):
 475         vserverimpl.killall(self.ctx, signal)
 476         self.vm_running = False
 477         self.rlimits_changed = False
 478
 479
 480
 481 def create(vm_name, static = False, ctor = VServer):
 482
 483     options = []
 484     if static:
 485         options += ['--static']
 486     runcmd.run('vuseradd', options + [vm_name])
 487     vm_id = pwd.getpwnam(vm_name)[2]
 488
 489     return ctor(vm_name, vm_id)