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.
29 class Sliver_VS(accounts.Account, vserver.VServer):
30 """This class wraps vserver.VServer to make its interface closer to what we need."""
33 TYPE = 'sliver.VServer'
35 def __init__(self, rec):
36 vserver.VServer.__init__(self, rec['name'])
40 self.disk_usage_initialized = False
44 def create(name): logger.log_call('/usr/sbin/vuseradd', name)
47 def destroy(name): logger.log_call('/usr/sbin/vuserdel', name)
49 def configure(self, rec):
50 new_rspec = rec['_rspec']
51 if new_rspec != self.rspec:
52 self.rspec = new_rspec
55 new_initscript = rec['initscript']
56 if new_initscript != self.initscript:
57 self.initscript = new_initscript
58 logger.log('%s: installing initscript' % self.name)
59 def install_initscript():
60 flags = os.O_WRONLY | os.O_CREAT | os.O_TRUNC
61 fd = os.open('/etc/rc.vinit', flags, 0755)
62 os.write(fd, new_initscript)
64 try: self.chroot_call(install_initscript)
65 except: logger.log_exc()
67 accounts.Account.configure(self, rec) # install ssh keys
69 def start(self, delay=0):
70 if self.rspec['enabled']:
71 logger.log('%s: starting in %d seconds' % (self.name, delay))
74 # VServer.start calls fork() internally, so just close the nonstandard fds and fork once to avoid creating zombies
75 tools.close_nonstandard_fds()
77 vserver.VServer.start(self, True)
79 else: os.waitpid(child_pid, 0)
80 else: logger.log('%s: not starting, is not enabled' % self.name)
83 logger.log('%s: stopping' % self.name)
84 vserver.VServer.stop(self)
86 def set_resources(self):
87 disk_max = self.rspec['disk_max']
88 logger.log('%s: setting max disk usage to %d KiB' % (self.name, disk_max))
89 try: # if the sliver is over quota, .set_disk_limit will throw an exception
90 if not self.disk_usage_initialized:
91 self.vm_running = False
92 logger.log('%s: computing disk usage' % self.name)
94 self.disk_usage_initialized = True
95 vserver.VServer.set_disklimit(self, disk_max)
97 logger.log('%s: failed to set max disk usage' % self.name)
100 net_limits = (self.rspec['net_min'], self.rspec['net_max'], self.rspec['net2_min'], self.rspec['net2_max'], self.rspec['net_share'])
101 logger.log('%s: setting net limits to %s bps' % (self.name, net_limits[:-1]))
102 logger.log('%s: setting net share to %d' % (self.name, net_limits[-1]))
103 self.set_bwlimit(*net_limits)
105 cpu_min = self.rspec['cpu_min']
106 cpu_share = self.rspec['cpu_share']
107 if self.rspec['enabled']:
108 if cpu_min >= 50: # at least 5%: keep people from shooting themselves in the foot
109 logger.log('%s: setting cpu share to %d%% guaranteed' % (self.name, cpu_min/10.0))
110 self.set_sched_config(cpu_min, vserver.SCHED_CPU_GUARANTEED)
112 logger.log('%s: setting cpu share to %d' % (self.name, cpu_share))
113 self.set_sched_config(cpu_share, 0)
114 else: # tell vsh to disable remote login by setting CPULIMIT to 0
115 logger.log('%s: disabling remote login' % self.name)
116 self.set_sched_config(0, 0)