xos/core/models/tenantwithcontainer.py

# Copyright 2017-present Open Networking Foundation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

from xos.exceptions import *
from tenantwithcontainer_decl import *

class TenantWithContainer(TenantWithContainer_decl):
    class Meta:
        proxy = True

    def __init__(self, *args, **kwargs):
        super(TenantWithContainer, self).__init__(*args, **kwargs)

        # vSG service relies on knowing when instance id has changed
        self.orig_instance_id = self.get_attribute("instance_id")

    # vSG service relies on instance_id attribute
    def get_attribute(self, name, default=None):
        if name=="instance_id":
            if self.instance:
                return self.instance.id
            else:
                return None
        else:
            return super(TenantWithContainer, self).get_attribute(name, default)

    # Services may wish to override the image() function to return different
    # images based on criteria in the tenant object. For example,
    #    if (self.has_feature_A):
    #        return Instance.object.get(name="image_with_feature_a")
    #    elif (self.has_feature_B):
    #        return Instance.object.get(name="image_with_feature_b")
    #    else:
    #        return super(MyTenantClass,self).image()

    @property
    def image(self):
        from core.models import Image
        # Implement the logic here to pick the image that should be used when
        # instantiating the VM that will hold the container.

        slice = self.provider_service.slices.all()
        if not slice:
            raise XOSProgrammingError("provider service has no slice")
        slice = slice[0]

        # If slice has default_image set then use it
        if slice.default_image:
            return slice.default_image

        raise XOSProgrammingError("Please set a default image for %s" % self.slice.name)

    def save_instance(self, instance):
        # Override this function to do custom pre-save or post-save processing,
        # such as creating ports for containers.
        instance.save()

    def pick_least_loaded_instance_in_slice(self, slices, image):
        for slice in slices:
            if slice.instances.all().count() > 0:
                for instance in slice.instances.all():
                    if instance.image != image:
                        continue
                    # Pick the first instance that has lesser than 5 tenants
                    if self.count_of_tenants_of_an_instance(instance) < 5:
                        return instance
        return None

    # TODO: Ideally the tenant count for an instance should be maintained using a
    # many-to-one relationship attribute, however this model being proxy, it does
    # not permit any new attributes to be defined. Find if any better solutions
    def count_of_tenants_of_an_instance(self, instance):
        tenant_count = 0
        for tenant in self.__class__.objects.all():
            if tenant.get_attribute("instance_id", None) == instance.id:
                tenant_count += 1
        return tenant_count

    def manage_container(self):
        from core.models import Instance, Flavor

        if self.deleted:
            return

        if (self.instance is not None) and (self.instance.image != self.image):
            self.instance.delete()
            self.instance = None

        if self.instance is None:
            if not self.provider_service.slices.count():
                raise XOSConfigurationError("The service has no slices")

            new_instance_created = False
            instance = None
            if self.get_attribute("use_same_instance_for_multiple_tenants", default=False):
                # Find if any existing instances can be used for this tenant
                slices = self.provider_service.slices.all()
                instance = self.pick_least_loaded_instance_in_slice(slices, self.image)

            if not instance:
                slice = self.provider_service.slices.all()[0]

                flavor = slice.default_flavor
                if not flavor:
                    flavors = Flavor.objects.filter(name="m1.small")
                    if not flavors:
                        raise XOSConfigurationError("No m1.small flavor")
                    flavor = flavors[0]

                if slice.default_isolation == "container_vm":
                    (node, parent) = ContainerVmScheduler(slice).pick()
                else:
                    (node, parent) = LeastLoadedNodeScheduler(slice).pick()

                instance = Instance(slice=slice,
                                    node=node,
                                    image=self.image,
                                    creator=self.creator,
                                    deployment=node.site_deployment.deployment,
                                    flavor=flavor,
                                    isolation=slice.default_isolation,
                                    parent=parent)
                self.save_instance(instance)
                new_instance_created = True

            try:
                self.instance = instance
                super(TenantWithContainer, self).save()
            except:
                if new_instance_created:
                    instance.delete()
                raise

    def cleanup_container(self):
        if self.instance:
            if self.get_attribute("use_same_instance_for_multiple_tenants", default=False):
                # Delete the instance only if this is last tenant in that
                # instance
                tenant_count = self.count_of_tenants_of_an_instance(
                    self.instance)
                if tenant_count == 0:
                    self.instance.delete()
            else:
                self.instance.delete()
            self.instance = None

    def save(self, *args, **kwargs):
        if (not self.creator) and (hasattr(self, "caller")) and (self.caller):
            self.creator = self.caller

        super(TenantWithContainer, self).save(*args, **kwargs)