3 There are a couple of tricky things going on here. First, the kernel
4 needs disk usage information in order to enforce the quota. However,
5 determining disk usage redundantly strains the disks. Thus, the
6 Sliver_VS.disk_usage_initialized flag is used to determine whether
7 this initialization has been made.
9 Second, it's not currently possible to set the scheduler parameters
10 for a sliver unless that sliver has a running process. /bin/vsh helps
11 us out by reading the configuration file so that it can set the
12 appropriate limits after entering the sliver context. Making the
13 syscall that actually sets the parameters gives a harmless error if no
14 process is running. Thus we keep vm_running on when setting scheduler
15 parameters so that set_sched_params() always makes the syscall, and we
16 don't have to guess if there is a running process or not.
30 class Sliver_VS(accounts.Account, vserver.VServer):
31 """This class wraps vserver.VServer to make its interface closer to what we need."""
34 TYPE = 'sliver.VServer'
35 _init_disk_info_sem = threading.Semaphore(1)
37 def __init__(self, rec):
39 vserver.VServer.__init__(self, rec['name'])
40 except vserver.NoSuchVServer:
41 self.create(rec['name'], rec['type'])
42 vserver.VServer.__init__(self, rec['name'])
47 self.disk_usage_initialized = False
51 def create(name, vref = None):
53 logger.log_call('/usr/sbin/vuseradd', '-t', vref, name)
55 logger.log_call('/usr/sbin/vuseradd', name)
58 def destroy(name): logger.log_call('/usr/sbin/vuserdel', name)
60 def configure(self, rec):
61 new_rspec = rec['_rspec']
62 if new_rspec != self.rspec:
63 self.rspec = new_rspec
66 new_initscript = rec['initscript']
67 if new_initscript != self.initscript:
68 self.initscript = new_initscript
69 logger.log('%s: installing initscript' % self.name)
70 def install_initscript():
71 flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC
72 fd = os.open('/etc/rc.vinit', flags, 0755)
73 os.write(fd, new_initscript)
75 try: self.chroot_call(install_initscript)
76 except: logger.log_exc()
78 accounts.Account.configure(self, rec) # install ssh keys
80 def start(self, delay=0):
81 if self.rspec['enabled']:
82 logger.log('%s: starting in %d seconds' % (self.name, delay))
85 # VServer.start calls fork() internally, so just close the nonstandard fds and fork once to avoid creating zombies
86 tools.close_nonstandard_fds()
88 vserver.VServer.start(self, True)
90 else: os.waitpid(child_pid, 0)
91 else: logger.log('%s: not starting, is not enabled' % self.name)
94 logger.log('%s: stopping' % self.name)
95 vserver.VServer.stop(self)
97 def set_resources(self):
98 disk_max = self.rspec['disk_max']
99 logger.log('%s: setting max disk usage to %d KiB' % (self.name, disk_max))
100 try: # if the sliver is over quota, .set_disk_limit will throw an exception
101 if not self.disk_usage_initialized:
102 self.vm_running = False
103 logger.log('%s: computing disk usage: beginning' % self.name)
104 Sliver_VS._init_disk_info_sem.acquire()
105 try: self.init_disk_info()
106 finally: Sliver_VS._init_disk_info_sem.release()
107 logger.log('%s: computing disk usage: ended' % self.name)
108 self.disk_usage_initialized = True
109 vserver.VServer.set_disklimit(self, disk_max)
111 logger.log('%s: failed to set max disk usage' % self.name)
114 net_limits = (self.rspec['net_min_rate'], self.rspec['net_max_rate'], self.rspec['net_i2_min_rate'], self.rspec['net_i2_max_rate'], self.rspec['net_share'])
115 logger.log('%s: setting net limits to %s bps' % (self.name, net_limits[:-1]))
116 logger.log('%s: setting net share to %d' % (self.name, net_limits[-1]))
117 self.set_bwlimit(*net_limits)
119 cpu_min = self.rspec['cpu_min']
120 cpu_share = self.rspec['cpu_share']
121 if self.rspec['enabled'] > 0:
122 if cpu_min >= 50: # at least 5%: keep people from shooting themselves in the foot
123 logger.log('%s: setting cpu share to %d%% guaranteed' % (self.name, cpu_min/10.0))
124 self.set_sched_config(cpu_min, vserver.SCHED_CPU_GUARANTEED)
126 logger.log('%s: setting cpu share to %d' % (self.name, cpu_share))
127 self.set_sched_config(cpu_share, 0)
128 else: # tell vsh to disable remote login by setting CPULIMIT to 0
129 logger.log('%s: disabling remote login' % self.name)
130 self.set_sched_config(0, 0)