node.py 10.3 KB
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from __future__ import absolute_import, unicode_literals
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from logging import getLogger

from django.db.models import (
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    CharField, IntegerField, ForeignKey, BooleanField, ManyToManyField,
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    FloatField, permalink,
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)
from django.utils.translation import ugettext_lazy as _

from celery.exceptions import TimeoutError
from model_utils.models import TimeStampedModel
from taggit.managers import TaggableManager

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from common.models import method_cache, WorkerNotFound
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from firewall.models import Host
from ..tasks import vm_tasks
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from .common import Trait
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from .activity import node_activity, NodeActivity
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from monitor.calvin.calvin import Query
from monitor.calvin.calvin import GraphiteHandler
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from django.utils import timezone
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logger = getLogger(__name__)


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def node_available(function):
    """Decorate methods to ignore disabled Nodes.
    """
    def decorate(self, *args, **kwargs):
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        if self.enabled and self.online:
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            return function(self, *args, **kwargs)
        else:
            return None
    return decorate


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class Node(TimeStampedModel):

    """A VM host machine, a hypervisor.
    """
    name = CharField(max_length=50, unique=True,
                     verbose_name=_('name'),
                     help_text=_('Human readable name of node.'))
    priority = IntegerField(verbose_name=_('priority'),
                            help_text=_('Node usage priority.'))
    host = ForeignKey(Host, verbose_name=_('host'),
                      help_text=_('Host in firewall.'))
    enabled = BooleanField(verbose_name=_('enabled'), default=False,
                           help_text=_('Indicates whether the node can '
                                       'be used for hosting.'))
    traits = ManyToManyField(Trait, blank=True,
                             help_text=_("Declared traits."),
                             verbose_name=_('traits'))
    tags = TaggableManager(blank=True, verbose_name=_("tags"))
    overcommit = FloatField(default=1.0, verbose_name=_("overcommit ratio"),
                            help_text=_("The ratio of total memory with "
                                        "to without overcommit."))

    class Meta:
        app_label = 'vm'
        db_table = 'vm_node'
        permissions = ()

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    def __unicode__(self):
        return self.name

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    @method_cache(10)
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    def get_online(self):
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        """Check if the node is online.
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        Check if node is online by queue is available.
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        """
        try:
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            self.get_remote_queue_name("vm")
        except:
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            return False
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        else:
            return True
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    online = property(get_online)

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    @node_available
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    @method_cache(300)
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    def get_num_cores(self):
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        """Number of CPU threads available to the virtual machines.
        """
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        return self.remote_query(vm_tasks.get_core_num, default=0)
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    num_cores = property(get_num_cores)

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    @property
    def state(self):
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        """The state combined of online and enabled attributes.
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        """
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        if self.enabled and self.online:
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            return 'ONLINE'
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        elif self.enabled and not self.online:
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            return 'MISSING'
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        elif not self.enabled and self.online:
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            return 'DISABLED'
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        else:
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            return 'OFFLINE'
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    def disable(self, user=None):
        ''' Disable the node.'''
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        if self.enabled:
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            with node_activity(code_suffix='disable', node=self, user=user):
                self.enabled = False
                self.save()
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    def enable(self, user=None):
        ''' Enable the node. '''
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        if self.enabled is not True:
            with node_activity(code_suffix='enable', node=self, user=user):
                self.enabled = True
                self.save()
            self.get_num_cores(invalidate_cache=True)
            self.get_ram_size(invalidate_cache=True)
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    @node_available
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    @method_cache(300)
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    def get_ram_size(self):
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        """Bytes of total memory in the node.
        """
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        return self.remote_query(vm_tasks.get_ram_size, default=0)
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    ram_size = property(get_ram_size)

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    @property
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    @node_available
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    def ram_size_with_overcommit(self):
        """Bytes of total memory including overcommit margin.
        """
        return self.ram_size * self.overcommit

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    @method_cache(30)
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    def get_remote_queue_name(self, queue_id):
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        """Return the name of the remote celery queue for this node.

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        throws Exception if there is no worker on the queue.
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        Until the cache provide reult there can be dead queues.
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        """
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        if vm_tasks.check_queue(self.host.hostname, queue_id):
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            self.node_online()
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            return self.host.hostname + "." + queue_id
        else:
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            if self.enabled:
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                self.node_offline()
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            raise WorkerNotFound()
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    def node_online(self):
        """Create activity and log entry when node reappears.
        """

        try:
            act = self.activity_log.order_by('-pk')[0]
        except IndexError:
            pass  # no monitoring activity at all
        else:
            logger.debug("The last activity was %s" % act)
            if act.activity_code.endswith("offline"):
                act = NodeActivity.create(code_suffix='monitor_succes_online',
                                          node=self, user=None)
                act.started = timezone.now()
                act.finished = timezone.now()
                act.succeeded = True
                act.save()
                logger.info("Node %s is ONLINE." % self.name)
                self.get_num_cores(invalidate_cache=True)
                self.get_ram_size(invalidate_cache=True)

    def node_offline(self):
        """Called when a node disappears.

        If the node is not already offline, record an activity and a log entry.
        """

        try:
            act = self.activity_log.order_by('-pk')[0]
        except IndexError:
            pass  # no activity at all
        else:
            logger.debug("The last activity was %s" % act)
            if act.activity_code.endswith("offline"):
                return
        act = NodeActivity.create(code_suffix='monitor_failed_offline',
                                  node=self, user=None)
        act.started = timezone.now()
        act.finished = timezone.now()
        act.succeeded = False
        act.save()
        logger.critical("Node %s is OFFLINE%s.", self.name,
                        ", but enabled" if self.enabled else "")
        # TODO: check if we should reschedule any VMs?

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    def remote_query(self, task, timeout=30, raise_=False, default=None):
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        """Query the given task, and get the result.

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        If the result is not ready or worker not reachable
        in timeout secs, return default value or raise a
        TimeoutError or WorkerNotFound exception.
        """
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        try:
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            r = task.apply_async(
                queue=self.get_remote_queue_name('vm'), expires=timeout + 60)
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            return r.get(timeout=timeout)
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        except (TimeoutError, WorkerNotFound):
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            if raise_:
                raise
            else:
                return default

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    @node_available
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    def get_monitor_info(self):
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        try:
            handler = GraphiteHandler()
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        except RuntimeError:
            return self.remote_query(vm_tasks.get_node_metrics, 30)

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        query = Query()
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        query.set_target(self.host.hostname + ".circle")
        query.set_format("json")
        query.set_relative_start(5, "minutes")
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        metrics = ["cpu.usage", "memory.usage"]
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        for metric in metrics:
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            query.set_metric(metric)
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            query.generate()
            handler.put(query)
            handler.send()
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        collected = {}
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        for metric in metrics:
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            response = handler.pop()
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            try:
                cache = response[0]["datapoints"][-1][0]
            except (IndexError, KeyError):
                cache = 0
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            if cache is None:
                cache = 0
            collected[metric] = cache
        return collected

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    @property
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    @node_available
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    def cpu_usage(self):
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        return float(self.get_monitor_info()["cpu.usage"]) / 100
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    @property
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    @node_available
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    def ram_usage(self):
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        return float(self.get_monitor_info()["memory.usage"]) / 100
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    @property
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    @node_available
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    def byte_ram_usage(self):
        return self.ram_usage * self.ram_size

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    @node_available
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    def update_vm_states(self):
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        """Update state of Instances running on this Node.

        Query state of all libvirt domains, and notify Instances by their
        vm_state_changed hook.
        """
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        domains = {}
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        domain_list = self.remote_query(vm_tasks.list_domains_info, timeout=5)
        if domain_list is None:
            logger.info("Monitoring failed at: %s", self.name)
            return
        for i in domain_list:
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            # [{'name': 'cloud-1234', 'state': 'RUNNING', ...}, ...]
            try:
                id = int(i['name'].split('-')[1])
            except:
                pass  # name format doesn't match
            else:
                domains[id] = i['state']

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        instances = [{'id': i.id, 'state': i.state}
                     for i in self.instance_set.order_by('id').all()]
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        for i in instances:
            try:
                d = domains[i['id']]
            except KeyError:
                logger.info('Node %s update: instance %s missing from '
                            'libvirt', self, i['id'])
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                # Set state to STOPPED when instance is missing
                self.instance_set.get(id=i['id']).vm_state_changed('STOPPED')
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            else:
                if d != i['state']:
                    logger.info('Node %s update: instance %s state changed '
                                '(libvirt: %s, db: %s)',
                                self, i['id'], d, i['state'])
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                    self.instance_set.get(id=i['id']).vm_state_changed(d)
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                del domains[i['id']]
        for i in domains.keys():
            logger.info('Node %s update: domain %s in libvirt but not in db.',
                        self, i)
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    @classmethod
    def get_state_count(cls, online, enabled):
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        return len([1 for i in cls.objects.filter(enabled=enabled).all()
                    if i.online == online])
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    @permalink
    def get_absolute_url(self):
        return ('dashboard.views.node-detail', None, {'pk': self.id})