models.py

# Copyright (c) 2011 X.commerce, a business unit of eBay Inc.
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2011 Piston Cloud Computing, Inc.
# All Rights Reserved.
#
#    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.
"""
SQLAlchemy models for nova data.
"""

from oslo_config import cfg
from oslo_db.sqlalchemy import models
from oslo_utils import timeutils
from sqlalchemy import (Column, Index, Integer, BigInteger, Enum, String,
                        schema, Unicode)
from sqlalchemy.dialects.mysql import MEDIUMTEXT
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import orm
from sqlalchemy import ForeignKey, DateTime, Boolean, Text, Float

from nova.db.sqlalchemy import types

CONF = cfg.CONF
BASE = declarative_base()


def MediumText():
    return Text().with_variant(MEDIUMTEXT(), 'mysql')


class NovaBase(models.TimestampMixin,
               models.ModelBase):
    metadata = None

    def __copy__(self):
        """Implement a safe copy.copy().

        SQLAlchemy-mapped objects travel with an object
        called an InstanceState, which is pegged to that object
        specifically and tracks everything about that object.  It's
        critical within all attribute operations, including gets
        and deferred loading.   This object definitely cannot be
        shared among two instances, and must be handled.

        The copy routine here makes use of session.merge() which
        already essentially implements a "copy" style of operation,
        which produces a new instance with a new InstanceState and copies
        all the data along mapped attributes without using any SQL.

        The mode we are using here has the caveat that the given object
        must be "clean", e.g. that it has no database-loaded state
        that has been updated and not flushed.   This is a good thing,
        as creating a copy of an object including non-flushed, pending
        database state is probably not a good idea; neither represents
        what the actual row looks like, and only one should be flushed.

        """
        session = orm.Session()

        copy = session.merge(self, load=False)
        session.expunge(copy)
        return copy


class Service(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a running service on a host."""

    __tablename__ = 'services'
    __table_args__ = (
        schema.UniqueConstraint("host", "topic", "deleted",
                                name="uniq_services0host0topic0deleted"),
        schema.UniqueConstraint("host", "binary", "deleted",
                                name="uniq_services0host0binary0deleted")
        )

    id = Column(Integer, primary_key=True)
    host = Column(String(255))  # , ForeignKey('hosts.id'))
    binary = Column(String(255))
    topic = Column(String(255))
    report_count = Column(Integer, nullable=False, default=0)
    disabled = Column(Boolean, default=False)
    disabled_reason = Column(String(255))
    last_seen_up = Column(DateTime, nullable=True)
    forced_down = Column(Boolean, default=False)
    version = Column(Integer, default=0)

    instance = orm.relationship(
        "Instance",
        backref='services',
        primaryjoin='and_(Service.host == Instance.host,'
                    'Service.binary == "nova-compute",'
                    'Instance.deleted == 0)',
        foreign_keys=host,
    )


class ComputeNode(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a running compute service on a host."""

    __tablename__ = 'compute_nodes'
    __table_args__ = (
        schema.UniqueConstraint(
            'host', 'hypervisor_hostname', 'deleted',
            name="uniq_compute_nodes0host0hypervisor_hostname0deleted"),
    )
    id = Column(Integer, primary_key=True)
    service_id = Column(Integer, nullable=True)

    # FIXME(sbauza: Host field is nullable because some old Juno compute nodes
    # can still report stats from an old ResourceTracker without setting this
    # field.
    # This field has to be set non-nullable in a later cycle (probably Lxxx)
    # once we are sure that all compute nodes in production report it.
    host = Column(String(255), nullable=True)
    uuid = Column(String(36), nullable=True)
    vcpus = Column(Integer, nullable=False)
    memory_mb = Column(Integer, nullable=False)
    local_gb = Column(Integer, nullable=False)
    vcpus_used = Column(Integer, nullable=False)
    memory_mb_used = Column(Integer, nullable=False)
    local_gb_used = Column(Integer, nullable=False)
    hypervisor_type = Column(MediumText(), nullable=False)
    hypervisor_version = Column(Integer, nullable=False)
    hypervisor_hostname = Column(String(255))

    # Free Ram, amount of activity (resize, migration, boot, etc) and
    # the number of running VM's are a good starting point for what's
    # important when making scheduling decisions.
    free_ram_mb = Column(Integer)
    free_disk_gb = Column(Integer)
    current_workload = Column(Integer)
    running_vms = Column(Integer)

    # Note(masumotok): Expected Strings example:
    #
    # '{"arch":"x86_64",
    #   "model":"Nehalem",
    #   "topology":{"sockets":1, "threads":2, "cores":3},
    #   "features":["tdtscp", "xtpr"]}'
    #
    # Points are "json translatable" and it must have all dictionary keys
    # above, since it is copied from <cpu> tag of getCapabilities()
    # (See libvirt.virtConnection).
    cpu_info = Column(MediumText(), nullable=False)
    disk_available_least = Column(Integer)
    host_ip = Column(types.IPAddress())
    supported_instances = Column(Text)
    metrics = Column(Text)

    # Note(yongli): json string PCI Stats
    # '[{"vendor_id":"8086", "product_id":"1234", "count":3 }, ...]'
    pci_stats = Column(Text)

    # extra_resources is a json string containing arbitrary
    # data about additional resources.
    extra_resources = Column(Text)

    # json-encode string containing compute node statistics
    stats = Column(Text, default='{}')

    # json-encoded dict that contains NUMA topology as generated by
    # objects.NUMATopoloogy._to_json()
    numa_topology = Column(Text)

    # allocation ratios provided by the RT
    ram_allocation_ratio = Column(Float, nullable=True)
    cpu_allocation_ratio = Column(Float, nullable=True)
    disk_allocation_ratio = Column(Float, nullable=True)


class Certificate(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a x509 certificate."""
    __tablename__ = 'certificates'
    __table_args__ = (
        Index('certificates_project_id_deleted_idx', 'project_id', 'deleted'),
        Index('certificates_user_id_deleted_idx', 'user_id', 'deleted')
    )
    id = Column(Integer, primary_key=True)

    user_id = Column(String(255))
    project_id = Column(String(255))
    file_name = Column(String(255))


class Instance(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a guest VM."""
    __tablename__ = 'instances'
    __table_args__ = (
        Index('uuid', 'uuid', unique=True),
        Index('instances_project_id_deleted_idx',
              'project_id', 'deleted'),
        Index('instances_reservation_id_idx',
              'reservation_id'),
        Index('instances_terminated_at_launched_at_idx',
              'terminated_at', 'launched_at'),
        Index('instances_uuid_deleted_idx',
              'uuid', 'deleted'),
        Index('instances_task_state_updated_at_idx',
              'task_state', 'updated_at'),
        Index('instances_host_node_deleted_idx',
              'host', 'node', 'deleted'),
        Index('instances_host_deleted_cleaned_idx',
              'host', 'deleted', 'cleaned'),
        Index('instances_deleted_created_at_idx',
              'deleted', 'created_at'),
        schema.UniqueConstraint('uuid', name='uniq_instances0uuid'),
    )
    injected_files = []

    id = Column(Integer, primary_key=True, autoincrement=True)

    @property
    def name(self):
        try:
            base_name = CONF.instance_name_template % self.id
        except TypeError:
            # Support templates like "uuid-%(uuid)s", etc.
            info = {}
            # NOTE(russellb): Don't use self.iteritems() here, as it will
            # result in infinite recursion on the name property.
            for column in iter(orm.object_mapper(self).columns):
                key = column.name
                # prevent recursion if someone specifies %(name)s
                # %(name)s will not be valid.
                if key == 'name':
                    continue
                info[key] = self[key]
            try:
                base_name = CONF.instance_name_template % info
            except KeyError:
                base_name = self.uuid
        return base_name

    @property
    def _extra_keys(self):
        return ['name']

    user_id = Column(String(255))
    project_id = Column(String(255))

    image_ref = Column(String(255))
    kernel_id = Column(String(255))
    ramdisk_id = Column(String(255))
    hostname = Column(String(255))

    launch_index = Column(Integer)
    key_name = Column(String(255))
    key_data = Column(MediumText())

    power_state = Column(Integer)
    vm_state = Column(String(255))
    task_state = Column(String(255))

    memory_mb = Column(Integer)
    vcpus = Column(Integer)
    root_gb = Column(Integer)
    ephemeral_gb = Column(Integer)
    ephemeral_key_uuid = Column(String(36))

    # This is not related to hostname, above.  It refers
    #  to the nova node.
    host = Column(String(255))  # , ForeignKey('hosts.id'))
    # To identify the "ComputeNode" which the instance resides in.
    # This equals to ComputeNode.hypervisor_hostname.
    node = Column(String(255))

    # *not* flavorid, this is the internal primary_key
    instance_type_id = Column(Integer)

    user_data = Column(MediumText())

    reservation_id = Column(String(255))

    # NOTE(sbiswas7): 'scheduled_at' is still in the database
    # and can be removed in the future release.

    launched_at = Column(DateTime)
    terminated_at = Column(DateTime)

    # This always refers to the availability_zone kwarg passed in /servers and
    # provided as an API option, not at all related to the host AZ the instance
    # belongs to.
    availability_zone = Column(String(255))

    # User editable field for display in user-facing UIs
    display_name = Column(String(255))
    display_description = Column(String(255))

    # To remember on which host an instance booted.
    # An instance may have moved to another host by live migration.
    launched_on = Column(MediumText())

    # NOTE(jdillaman): locked deprecated in favor of locked_by,
    # to be removed in Icehouse
    locked = Column(Boolean)
    locked_by = Column(Enum('owner', 'admin'))

    os_type = Column(String(255))
    architecture = Column(String(255))
    vm_mode = Column(String(255))
    uuid = Column(String(36), nullable=False)

    root_device_name = Column(String(255))
    default_ephemeral_device = Column(String(255))
    default_swap_device = Column(String(255))
    config_drive = Column(String(255))

    # User editable field meant to represent what ip should be used
    # to connect to the instance
    access_ip_v4 = Column(types.IPAddress())
    access_ip_v6 = Column(types.IPAddress())

    auto_disk_config = Column(Boolean())
    progress = Column(Integer)

    # EC2 instance_initiated_shutdown_terminate
    # True: -> 'terminate'
    # False: -> 'stop'
    # Note(maoy): currently Nova will always stop instead of terminate
    # no matter what the flag says. So we set the default to False.
    shutdown_terminate = Column(Boolean(), default=False)

    # EC2 disable_api_termination
    disable_terminate = Column(Boolean(), default=False)

    # OpenStack compute cell name.  This will only be set at the top of
    # the cells tree and it'll be a full cell name such as 'api!hop1!hop2'
    cell_name = Column(String(255))
    internal_id = Column(Integer)

    # Records whether an instance has been deleted from disk
    cleaned = Column(Integer, default=0)


class InstanceInfoCache(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a cache of information about an instance
    """
    __tablename__ = 'instance_info_caches'
    __table_args__ = (
        schema.UniqueConstraint(
            "instance_uuid",
            name="uniq_instance_info_caches0instance_uuid"),)
    id = Column(Integer, primary_key=True, autoincrement=True)

    # text column used for storing a json object of network data for api
    network_info = Column(MediumText())

    instance_uuid = Column(String(36), ForeignKey('instances.uuid'),
                           nullable=False)
    instance = orm.relationship(Instance,
                            backref=orm.backref('info_cache', uselist=False),
                            foreign_keys=instance_uuid,
                            primaryjoin=instance_uuid == Instance.uuid)


class InstanceExtra(BASE, NovaBase, models.SoftDeleteMixin):
    __tablename__ = 'instance_extra'
    __table_args__ = (
        Index('instance_extra_idx', 'instance_uuid'),)
    id = Column(Integer, primary_key=True, autoincrement=True)
    instance_uuid = Column(String(36), ForeignKey('instances.uuid'),
                           nullable=False)
    numa_topology = orm.deferred(Column(Text))
    pci_requests = orm.deferred(Column(Text))
    flavor = orm.deferred(Column(Text))
    vcpu_model = orm.deferred(Column(Text))
    migration_context = orm.deferred(Column(Text))
    instance = orm.relationship(Instance,
                            backref=orm.backref('extra',
                                                uselist=False),
                            foreign_keys=instance_uuid,
                            primaryjoin=instance_uuid == Instance.uuid)


class InstanceTypes(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents possible flavors for instances.

    Note: instance_type and flavor are synonyms and the term instance_type is
    deprecated and in the process of being removed.
    """
    __tablename__ = "instance_types"

    __table_args__ = (
        schema.UniqueConstraint("flavorid", "deleted",
                                name="uniq_instance_types0flavorid0deleted"),
        schema.UniqueConstraint("name", "deleted",
                                name="uniq_instance_types0name0deleted")
    )

    # Internal only primary key/id
    id = Column(Integer, primary_key=True)
    name = Column(String(255))
    memory_mb = Column(Integer, nullable=False)
    vcpus = Column(Integer, nullable=False)
    root_gb = Column(Integer)
    ephemeral_gb = Column(Integer)
    # Public facing id will be renamed public_id
    flavorid = Column(String(255))
    swap = Column(Integer, nullable=False, default=0)
    rxtx_factor = Column(Float, default=1)
    vcpu_weight = Column(Integer)
    disabled = Column(Boolean, default=False)
    is_public = Column(Boolean, default=True)


class Quota(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a single quota override for a project.

    If there is no row for a given project id and resource, then the
    default for the quota class is used.  If there is no row for a
    given quota class and resource, then the default for the
    deployment is used. If the row is present but the hard limit is
    Null, then the resource is unlimited.
    """

    __tablename__ = 'quotas'
    __table_args__ = (
        schema.UniqueConstraint("project_id", "resource", "deleted",
        name="uniq_quotas0project_id0resource0deleted"
        ),
    )
    id = Column(Integer, primary_key=True)

    project_id = Column(String(255))

    resource = Column(String(255), nullable=False)
    hard_limit = Column(Integer)


class ProjectUserQuota(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a single quota override for a user with in a project."""

    __tablename__ = 'project_user_quotas'
    uniq_name = "uniq_project_user_quotas0user_id0project_id0resource0deleted"
    __table_args__ = (
        schema.UniqueConstraint("user_id", "project_id", "resource", "deleted",
                                name=uniq_name),
        Index('project_user_quotas_project_id_deleted_idx',
              'project_id', 'deleted'),
        Index('project_user_quotas_user_id_deleted_idx',
              'user_id', 'deleted')
    )
    id = Column(Integer, primary_key=True, nullable=False)

    project_id = Column(String(255), nullable=False)
    user_id = Column(String(255), nullable=False)

    resource = Column(String(255), nullable=False)
    hard_limit = Column(Integer)


class QuotaClass(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a single quota override for a quota class.

    If there is no row for a given quota class and resource, then the
    default for the deployment is used.  If the row is present but the
    hard limit is Null, then the resource is unlimited.
    """

    __tablename__ = 'quota_classes'
    __table_args__ = (
        Index('ix_quota_classes_class_name', 'class_name'),
    )
    id = Column(Integer, primary_key=True)

    class_name = Column(String(255))

    resource = Column(String(255))
    hard_limit = Column(Integer)


class QuotaUsage(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents the current usage for a given resource."""

    __tablename__ = 'quota_usages'
    __table_args__ = (
        Index('ix_quota_usages_project_id', 'project_id'),
        Index('ix_quota_usages_user_id_deleted', 'user_id', 'deleted'),
    )
    id = Column(Integer, primary_key=True)

    project_id = Column(String(255))
    user_id = Column(String(255))
    resource = Column(String(255), nullable=False)

    in_use = Column(Integer, nullable=False)
    reserved = Column(Integer, nullable=False)

    @property
    def total(self):
        return self.in_use + self.reserved

    until_refresh = Column(Integer)


class Reservation(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a resource reservation for quotas."""

    __tablename__ = 'reservations'
    __table_args__ = (
        Index('ix_reservations_project_id', 'project_id'),
        Index('reservations_uuid_idx', 'uuid'),
        Index('reservations_deleted_expire_idx', 'deleted', 'expire'),
        Index('ix_reservations_user_id_deleted', 'user_id', 'deleted'),
    )
    id = Column(Integer, primary_key=True, nullable=False)
    uuid = Column(String(36), nullable=False)

    usage_id = Column(Integer, ForeignKey('quota_usages.id'), nullable=False)

    project_id = Column(String(255))
    user_id = Column(String(255))
    resource = Column(String(255))

    delta = Column(Integer, nullable=False)
    expire = Column(DateTime)

    usage = orm.relationship(
        "QuotaUsage",
        foreign_keys=usage_id,
        primaryjoin='and_(Reservation.usage_id == QuotaUsage.id,'
                         'QuotaUsage.deleted == 0)')


class Snapshot(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a block storage device that can be attached to a VM."""
    __tablename__ = 'snapshots'
    __table_args__ = ()
    id = Column(String(36), primary_key=True, nullable=False)
    deleted = Column(String(36), default="")

    @property
    def name(self):
        return CONF.snapshot_name_template % self.id

    @property
    def volume_name(self):
        return CONF.volume_name_template % self.volume_id

    user_id = Column(String(255))
    project_id = Column(String(255))

    volume_id = Column(String(36), nullable=False)
    status = Column(String(255))
    progress = Column(String(255))
    volume_size = Column(Integer)
    scheduled_at = Column(DateTime)

    display_name = Column(String(255))
    display_description = Column(String(255))


class BlockDeviceMapping(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents block device mapping that is defined by EC2."""
    __tablename__ = "block_device_mapping"
    __table_args__ = (
        Index('snapshot_id', 'snapshot_id'),
        Index('volume_id', 'volume_id'),
        Index('block_device_mapping_instance_uuid_device_name_idx',
              'instance_uuid', 'device_name'),
        Index('block_device_mapping_instance_uuid_volume_id_idx',
              'instance_uuid', 'volume_id'),
        Index('block_device_mapping_instance_uuid_idx', 'instance_uuid'),
    )
    id = Column(Integer, primary_key=True, autoincrement=True)

    instance_uuid = Column(String(36), ForeignKey('instances.uuid'))
    instance = orm.relationship(Instance,
                            backref=orm.backref('block_device_mapping'),
                            foreign_keys=instance_uuid,
                            primaryjoin='and_(BlockDeviceMapping.'
                                              'instance_uuid=='
                                              'Instance.uuid,'
                                              'BlockDeviceMapping.deleted=='
                                              '0)')

    source_type = Column(String(255))
    destination_type = Column(String(255))
    guest_format = Column(String(255))
    device_type = Column(String(255))
    disk_bus = Column(String(255))

    boot_index = Column(Integer)

    device_name = Column(String(255))

    # default=False for compatibility of the existing code.
    # With EC2 API,
    # default True for ami specified device.
    # default False for created with other timing.
    # TODO(sshturm) add default in db
    delete_on_termination = Column(Boolean, default=False)

    snapshot_id = Column(String(36))

    volume_id = Column(String(36))
    volume_size = Column(Integer)

    image_id = Column(String(36))

    # for no device to suppress devices.
    no_device = Column(Boolean)

    connection_info = Column(MediumText())


class SecurityGroupInstanceAssociation(BASE, NovaBase, models.SoftDeleteMixin):
    __tablename__ = 'security_group_instance_association'
    __table_args__ = (
        Index('security_group_instance_association_instance_uuid_idx',
              'instance_uuid'),
    )
    id = Column(Integer, primary_key=True, nullable=False)
    security_group_id = Column(Integer, ForeignKey('security_groups.id'))
    instance_uuid = Column(String(36), ForeignKey('instances.uuid'))


class SecurityGroup(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a security group."""
    __tablename__ = 'security_groups'
    __table_args__ = (
        schema.UniqueConstraint('project_id', 'name', 'deleted',
                                name='uniq_security_groups0project_id0'
                                     'name0deleted'),
    )
    id = Column(Integer, primary_key=True)

    name = Column(String(255))
    description = Column(String(255))
    user_id = Column(String(255))
    project_id = Column(String(255))

    instances = orm.relationship(Instance,
                             secondary="security_group_instance_association",
                             primaryjoin='and_('
        'SecurityGroup.id == '
        'SecurityGroupInstanceAssociation.security_group_id,'
        'SecurityGroupInstanceAssociation.deleted == 0,'
        'SecurityGroup.deleted == 0)',
                             secondaryjoin='and_('
        'SecurityGroupInstanceAssociation.instance_uuid == Instance.uuid,'
        # (anthony) the condition below shouldn't be necessary now that the
        # association is being marked as deleted.  However, removing this
        # may cause existing deployments to choke, so I'm leaving it
        'Instance.deleted == 0)',
                             backref='security_groups')


class SecurityGroupIngressRule(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a rule in a security group."""
    __tablename__ = 'security_group_rules'
    __table_args__ = ()
    id = Column(Integer, primary_key=True)

    parent_group_id = Column(Integer, ForeignKey('security_groups.id'))
    parent_group = orm.relationship("SecurityGroup", backref="rules",
                                foreign_keys=parent_group_id,
                                primaryjoin='and_('
        'SecurityGroupIngressRule.parent_group_id == SecurityGroup.id,'
        'SecurityGroupIngressRule.deleted == 0)')

    protocol = Column(String(255))
    from_port = Column(Integer)
    to_port = Column(Integer)
    cidr = Column(types.CIDR())

    # Note: This is not the parent SecurityGroup. It's SecurityGroup we're
    # granting access for.
    group_id = Column(Integer, ForeignKey('security_groups.id'))
    grantee_group = orm.relationship("SecurityGroup",
                                 foreign_keys=group_id,
                                 primaryjoin='and_('
        'SecurityGroupIngressRule.group_id == SecurityGroup.id,'
        'SecurityGroupIngressRule.deleted == 0)')


class SecurityGroupIngressDefaultRule(BASE, NovaBase, models.SoftDeleteMixin):
    __tablename__ = 'security_group_default_rules'
    __table_args__ = ()
    id = Column(Integer, primary_key=True, nullable=False)
    protocol = Column(String(5))  # "tcp", "udp" or "icmp"
    from_port = Column(Integer)
    to_port = Column(Integer)
    cidr = Column(types.CIDR())


class ProviderFirewallRule(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a rule in a security group."""
    __tablename__ = 'provider_fw_rules'
    __table_args__ = ()
    id = Column(Integer, primary_key=True, nullable=False)

    protocol = Column(String(5))  # "tcp", "udp", or "icmp"
    from_port = Column(Integer)
    to_port = Column(Integer)
    cidr = Column(types.CIDR())


class KeyPair(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a public key pair for ssh / WinRM."""
    __tablename__ = 'key_pairs'
    __table_args__ = (
        schema.UniqueConstraint("user_id", "name", "deleted",
                                name="uniq_key_pairs0user_id0name0deleted"),
    )
    id = Column(Integer, primary_key=True, nullable=False)

    name = Column(String(255), nullable=False)

    user_id = Column(String(255))

    fingerprint = Column(String(255))
    public_key = Column(MediumText())
    type = Column(Enum('ssh', 'x509', name='keypair_types'),
                  nullable=False, server_default='ssh')


class Migration(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a running host-to-host migration."""
    __tablename__ = 'migrations'
    __table_args__ = (
        Index('migrations_instance_uuid_and_status_idx', 'deleted',
              'instance_uuid', 'status'),
        Index('migrations_by_host_nodes_and_status_idx', 'deleted',
              'source_compute', 'dest_compute', 'source_node', 'dest_node',
              'status'),
    )
    id = Column(Integer, primary_key=True, nullable=False)
    # NOTE(tr3buchet): the ____compute variables are instance['host']
    source_compute = Column(String(255))
    dest_compute = Column(String(255))
    # nodes are equivalent to a compute node's 'hypervisor_hostname'
    source_node = Column(String(255))
    dest_node = Column(String(255))
    # NOTE(tr3buchet): dest_host, btw, is an ip address
    dest_host = Column(String(255))
    old_instance_type_id = Column(Integer())
    new_instance_type_id = Column(Integer())
    instance_uuid = Column(String(36), ForeignKey('instances.uuid'))
    # TODO(_cerberus_): enum
    status = Column(String(255))
    migration_type = Column(Enum('migration', 'resize', 'live-migration',
                                 'evacuation'),
                            nullable=True)
    hidden = Column(Boolean, default=False)
    memory_total = Column(BigInteger, nullable=True)
    memory_processed = Column(BigInteger, nullable=True)
    memory_remaining = Column(BigInteger, nullable=True)
    disk_total = Column(BigInteger, nullable=True)
    disk_processed = Column(BigInteger, nullable=True)
    disk_remaining = Column(BigInteger, nullable=True)

    instance = orm.relationship("Instance", foreign_keys=instance_uuid,
                            primaryjoin='and_(Migration.instance_uuid == '
                                        'Instance.uuid, Instance.deleted == '
                                        '0)')


class Network(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a network."""
    __tablename__ = 'networks'
    __table_args__ = (
        schema.UniqueConstraint("vlan", "deleted",
                                name="uniq_networks0vlan0deleted"),
       Index('networks_bridge_deleted_idx', 'bridge', 'deleted'),
       Index('networks_host_idx', 'host'),
       Index('networks_project_id_deleted_idx', 'project_id', 'deleted'),
       Index('networks_uuid_project_id_deleted_idx', 'uuid',
             'project_id', 'deleted'),
       Index('networks_vlan_deleted_idx', 'vlan', 'deleted'),
       Index('networks_cidr_v6_idx', 'cidr_v6')
    )

    id = Column(Integer, primary_key=True, nullable=False)
    label = Column(String(255))

    injected = Column(Boolean, default=False)
    cidr = Column(types.CIDR())
    cidr_v6 = Column(types.CIDR())
    multi_host = Column(Boolean, default=False)

    gateway_v6 = Column(types.IPAddress())
    netmask_v6 = Column(types.IPAddress())
    netmask = Column(types.IPAddress())
    bridge = Column(String(255))
    bridge_interface = Column(String(255))
    gateway = Column(types.IPAddress())
    broadcast = Column(types.IPAddress())
    dns1 = Column(types.IPAddress())
    dns2 = Column(types.IPAddress())

    vlan = Column(Integer)
    vpn_public_address = Column(types.IPAddress())
    vpn_public_port = Column(Integer)
    vpn_private_address = Column(types.IPAddress())
    dhcp_start = Column(types.IPAddress())

    rxtx_base = Column(Integer)

    project_id = Column(String(255))
    priority = Column(Integer)
    host = Column(String(255))  # , ForeignKey('hosts.id'))
    uuid = Column(String(36))

    mtu = Column(Integer)
    dhcp_server = Column(types.IPAddress())
    enable_dhcp = Column(Boolean, default=True)
    share_address = Column(Boolean, default=False)


class VirtualInterface(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a virtual interface on an instance."""
    __tablename__ = 'virtual_interfaces'
    __table_args__ = (
        schema.UniqueConstraint("address", "deleted",
                        name="uniq_virtual_interfaces0address0deleted"),
        Index('virtual_interfaces_network_id_idx', 'network_id'),
        Index('virtual_interfaces_instance_uuid_fkey', 'instance_uuid'),
        Index('virtual_interfaces_uuid_idx', 'uuid'),
    )
    id = Column(Integer, primary_key=True, nullable=False)
    address = Column(String(255))
    network_id = Column(Integer)
    instance_uuid = Column(String(36), ForeignKey('instances.uuid'))
    uuid = Column(String(36))


# TODO(vish): can these both come from the same baseclass?
class FixedIp(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a fixed IP for an instance."""
    __tablename__ = 'fixed_ips'
    __table_args__ = (
        schema.UniqueConstraint(
            "address", "deleted", name="uniq_fixed_ips0address0deleted"),
        Index('fixed_ips_virtual_interface_id_fkey', 'virtual_interface_id'),
        Index('network_id', 'network_id'),
        Index('address', 'address'),
        Index('fixed_ips_instance_uuid_fkey', 'instance_uuid'),
        Index('fixed_ips_host_idx', 'host'),
        Index('fixed_ips_network_id_host_deleted_idx', 'network_id', 'host',
              'deleted'),
        Index('fixed_ips_address_reserved_network_id_deleted_idx',
              'address', 'reserved', 'network_id', 'deleted'),
        Index('fixed_ips_deleted_allocated_idx', 'address', 'deleted',
              'allocated'),
        Index('fixed_ips_deleted_allocated_updated_at_idx', 'deleted',
              'allocated', 'updated_at')
    )
    id = Column(Integer, primary_key=True)
    address = Column(types.IPAddress())
    network_id = Column(Integer)
    virtual_interface_id = Column(Integer)
    instance_uuid = Column(String(36), ForeignKey('instances.uuid'))
    # associated means that a fixed_ip has its instance_id column set
    # allocated means that a fixed_ip has its virtual_interface_id column set
    # TODO(sshturm) add default in db
    allocated = Column(Boolean, default=False)
    # leased means dhcp bridge has leased the ip
    # TODO(sshturm) add default in db
    leased = Column(Boolean, default=False)
    # TODO(sshturm) add default in db
    reserved = Column(Boolean, default=False)
    host = Column(String(255))
    network = orm.relationship(Network,
                           backref=orm.backref('fixed_ips'),
                           foreign_keys=network_id,
                           primaryjoin='and_('
                                'FixedIp.network_id == Network.id,'
                                'FixedIp.deleted == 0,'
                                'Network.deleted == 0)')
    instance = orm.relationship(Instance,
                            foreign_keys=instance_uuid,
                            primaryjoin='and_('
                                'FixedIp.instance_uuid == Instance.uuid,'
                                'FixedIp.deleted == 0,'
                                'Instance.deleted == 0)')
    virtual_interface = orm.relationship(VirtualInterface,
                           backref=orm.backref('fixed_ips'),
                           foreign_keys=virtual_interface_id,
                           primaryjoin='and_('
                                'FixedIp.virtual_interface_id == '
                                'VirtualInterface.id,'
                                'FixedIp.deleted == 0,'
                                'VirtualInterface.deleted == 0)')


class FloatingIp(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a floating IP that dynamically forwards to a fixed IP."""
    __tablename__ = 'floating_ips'
    __table_args__ = (
        schema.UniqueConstraint("address", "deleted",
                                name="uniq_floating_ips0address0deleted"),
        Index('fixed_ip_id', 'fixed_ip_id'),
        Index('floating_ips_host_idx', 'host'),
        Index('floating_ips_project_id_idx', 'project_id'),
        Index('floating_ips_pool_deleted_fixed_ip_id_project_id_idx',
              'pool', 'deleted', 'fixed_ip_id', 'project_id')
    )
    id = Column(Integer, primary_key=True)
    address = Column(types.IPAddress())
    fixed_ip_id = Column(Integer)
    project_id = Column(String(255))
    host = Column(String(255))  # , ForeignKey('hosts.id'))
    auto_assigned = Column(Boolean, default=False)
    # TODO(sshturm) add default in db
    pool = Column(String(255))
    interface = Column(String(255))
    fixed_ip = orm.relationship(FixedIp,
                            backref=orm.backref('floating_ips'),
                            foreign_keys=fixed_ip_id,
                            primaryjoin='and_('
                                'FloatingIp.fixed_ip_id == FixedIp.id,'
                                'FloatingIp.deleted == 0,'
                                'FixedIp.deleted == 0)')


class DNSDomain(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a DNS domain with availability zone or project info."""
    __tablename__ = 'dns_domains'
    __table_args__ = (
        Index('dns_domains_project_id_idx', 'project_id'),
        Index('dns_domains_domain_deleted_idx', 'domain', 'deleted'),
    )
    deleted = Column(Boolean, default=False)
    domain = Column(String(255), primary_key=True)
    scope = Column(String(255))
    availability_zone = Column(String(255))
    project_id = Column(String(255))


class ConsolePool(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents pool of consoles on the same physical node."""
    __tablename__ = 'console_pools'
    __table_args__ = (
        schema.UniqueConstraint(
            "host", "console_type", "compute_host", "deleted",
            name="uniq_console_pools0host0console_type0compute_host0deleted"),
    )
    id = Column(Integer, primary_key=True)
    address = Column(types.IPAddress())
    username = Column(String(255))
    password = Column(String(255))
    console_type = Column(String(255))
    public_hostname = Column(String(255))
    host = Column(String(255))
    compute_host = Column(String(255))


class Console(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a console session for an instance."""
    __tablename__ = 'consoles'
    __table_args__ = (
        Index('consoles_instance_uuid_idx', 'instance_uuid'),
    )
    id = Column(Integer, primary_key=True)
    instance_name = Column(String(255))
    instance_uuid = Column(String(36), ForeignKey('instances.uuid'))
    password = Column(String(255))
    port = Column(Integer)
    pool_id = Column(Integer, ForeignKey('console_pools.id'))
    pool = orm.relationship(ConsolePool, backref=orm.backref('consoles'))


class InstanceMetadata(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a user-provided metadata key/value pair for an instance."""
    __tablename__ = 'instance_metadata'
    __table_args__ = (
        Index('instance_metadata_instance_uuid_idx', 'instance_uuid'),
    )
    id = Column(Integer, primary_key=True)
    key = Column(String(255))
    value = Column(String(255))
    instance_uuid = Column(String(36), ForeignKey('instances.uuid'))
    instance = orm.relationship(Instance, backref="metadata",
                            foreign_keys=instance_uuid,
                            primaryjoin='and_('
                                'InstanceMetadata.instance_uuid == '
                                     'Instance.uuid,'
                                'InstanceMetadata.deleted == 0)')


class InstanceSystemMetadata(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a system-owned metadata key/value pair for an instance."""
    __tablename__ = 'instance_system_metadata'
    __table_args__ = (
        Index('instance_uuid', 'instance_uuid'),
    )
    id = Column(Integer, primary_key=True)
    key = Column(String(255), nullable=False)
    value = Column(String(255))
    instance_uuid = Column(String(36),
                           ForeignKey('instances.uuid'),
                           nullable=False)

    instance = orm.relationship(Instance, backref="system_metadata",
                            foreign_keys=instance_uuid)


class InstanceTypeProjects(BASE, NovaBase, models.SoftDeleteMixin):
    """Represent projects associated instance_types."""
    __tablename__ = "instance_type_projects"
    __table_args__ = (schema.UniqueConstraint(
        "instance_type_id", "project_id", "deleted",
        name="uniq_instance_type_projects0instance_type_id0project_id0deleted"
        ),
    )
    id = Column(Integer, primary_key=True)
    instance_type_id = Column(Integer, ForeignKey('instance_types.id'),
                              nullable=False)
    project_id = Column(String(255))

    instance_type = orm.relationship(InstanceTypes, backref="projects",
                 foreign_keys=instance_type_id,
                 primaryjoin='and_('
                 'InstanceTypeProjects.instance_type_id == InstanceTypes.id,'
                 'InstanceTypeProjects.deleted == 0)')


class InstanceTypeExtraSpecs(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents additional specs as key/value pairs for an instance_type."""
    __tablename__ = 'instance_type_extra_specs'
    __table_args__ = (
        Index('instance_type_extra_specs_instance_type_id_key_idx',
              'instance_type_id', 'key'),
        schema.UniqueConstraint(
              "instance_type_id", "key", "deleted",
              name=("uniq_instance_type_extra_specs0"
                    "instance_type_id0key0deleted")
        ),
        {'mysql_collate': 'utf8_bin'},
    )
    id = Column(Integer, primary_key=True)
    key = Column(String(255))
    value = Column(String(255))
    instance_type_id = Column(Integer, ForeignKey('instance_types.id'),
                              nullable=False)
    instance_type = orm.relationship(InstanceTypes, backref="extra_specs",
                 foreign_keys=instance_type_id,
                 primaryjoin='and_('
                 'InstanceTypeExtraSpecs.instance_type_id == InstanceTypes.id,'
                 'InstanceTypeExtraSpecs.deleted == 0)')


class Cell(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents parent and child cells of this cell.  Cells can
    have multiple parents and children, so there could be any number
    of entries with is_parent=True or False
    """
    __tablename__ = 'cells'
    __table_args__ = (schema.UniqueConstraint(
        "name", "deleted", name="uniq_cells0name0deleted"
        ),
    )
    id = Column(Integer, primary_key=True)
    # Name here is the 'short name' of a cell.  For instance: 'child1'
    name = Column(String(255))
    api_url = Column(String(255))

    transport_url = Column(String(255), nullable=False)

    weight_offset = Column(Float(), default=0.0)
    weight_scale = Column(Float(), default=1.0)
    is_parent = Column(Boolean())


class AggregateHost(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a host that is member of an aggregate."""
    __tablename__ = 'aggregate_hosts'
    __table_args__ = (schema.UniqueConstraint(
        "host", "aggregate_id", "deleted",
         name="uniq_aggregate_hosts0host0aggregate_id0deleted"
        ),
    )
    id = Column(Integer, primary_key=True, autoincrement=True)
    host = Column(String(255))
    aggregate_id = Column(Integer, ForeignKey('aggregates.id'), nullable=False)


class AggregateMetadata(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a metadata key/value pair for an aggregate."""
    __tablename__ = 'aggregate_metadata'
    __table_args__ = (
        schema.UniqueConstraint("aggregate_id", "key", "deleted",
            name="uniq_aggregate_metadata0aggregate_id0key0deleted"
            ),
        Index('aggregate_metadata_key_idx', 'key'),
    )
    id = Column(Integer, primary_key=True)
    key = Column(String(255), nullable=False)
    value = Column(String(255), nullable=False)
    aggregate_id = Column(Integer, ForeignKey('aggregates.id'), nullable=False)


class Aggregate(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a cluster of hosts that exists in this zone."""
    __tablename__ = 'aggregates'
    __table_args__ = (Index('aggregate_uuid_idx', 'uuid'),)
    id = Column(Integer, primary_key=True, autoincrement=True)
    uuid = Column(String(36))
    name = Column(String(255))
    _hosts = orm.relationship(AggregateHost,
                          primaryjoin='and_('
                          'Aggregate.id == AggregateHost.aggregate_id,'
                          'AggregateHost.deleted == 0,'
                          'Aggregate.deleted == 0)')

    _metadata = orm.relationship(AggregateMetadata,
                             primaryjoin='and_('
                             'Aggregate.id == AggregateMetadata.aggregate_id,'
                             'AggregateMetadata.deleted == 0,'
                             'Aggregate.deleted == 0)')

    @property
    def _extra_keys(self):
        return ['hosts', 'metadetails', 'availability_zone']

    @property
    def hosts(self):
        return [h.host for h in self._hosts]

    @property
    def metadetails(self):
        return {m.key: m.value for m in self._metadata}

    @property
    def availability_zone(self):
        if 'availability_zone' not in self.metadetails:
            return None
        return self.metadetails['availability_zone']


class AgentBuild(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents an agent build."""
    __tablename__ = 'agent_builds'
    __table_args__ = (
        Index('agent_builds_hypervisor_os_arch_idx', 'hypervisor', 'os',
              'architecture'),
        schema.UniqueConstraint("hypervisor", "os", "architecture", "deleted",
                name="uniq_agent_builds0hypervisor0os0architecture0deleted"),
    )
    id = Column(Integer, primary_key=True)
    hypervisor = Column(String(255))
    os = Column(String(255))
    architecture = Column(String(255))
    version = Column(String(255))
    url = Column(String(255))
    md5hash = Column(String(255))


class BandwidthUsage(BASE, NovaBase, models.SoftDeleteMixin):
    """Cache for instance bandwidth usage data pulled from the hypervisor."""
    __tablename__ = 'bw_usage_cache'
    __table_args__ = (
        Index('bw_usage_cache_uuid_start_period_idx', 'uuid',
              'start_period'),
    )
    id = Column(Integer, primary_key=True, nullable=False)
    uuid = Column(String(36))
    mac = Column(String(255))
    start_period = Column(DateTime, nullable=False)
    last_refreshed = Column(DateTime)
    bw_in = Column(BigInteger)
    bw_out = Column(BigInteger)
    last_ctr_in = Column(BigInteger)
    last_ctr_out = Column(BigInteger)


class VolumeUsage(BASE, NovaBase, models.SoftDeleteMixin):
    """Cache for volume usage data pulled from the hypervisor."""
    __tablename__ = 'volume_usage_cache'
    __table_args__ = ()
    id = Column(Integer, primary_key=True, nullable=False)
    volume_id = Column(String(36), nullable=False)
    instance_uuid = Column(String(36))
    project_id = Column(String(36))
    user_id = Column(String(64))
    availability_zone = Column(String(255))
    tot_last_refreshed = Column(DateTime)
    tot_reads = Column(BigInteger, default=0)
    tot_read_bytes = Column(BigInteger, default=0)
    tot_writes = Column(BigInteger, default=0)
    tot_write_bytes = Column(BigInteger, default=0)
    curr_last_refreshed = Column(DateTime)
    curr_reads = Column(BigInteger, default=0)
    curr_read_bytes = Column(BigInteger, default=0)
    curr_writes = Column(BigInteger, default=0)
    curr_write_bytes = Column(BigInteger, default=0)


class S3Image(BASE, NovaBase, models.SoftDeleteMixin):
    """Compatibility layer for the S3 image service talking to Glance."""
    __tablename__ = 's3_images'
    __table_args__ = ()
    id = Column(Integer, primary_key=True, nullable=False, autoincrement=True)
    uuid = Column(String(36), nullable=False)


class VolumeIdMapping(BASE, NovaBase, models.SoftDeleteMixin):
    """Compatibility layer for the EC2 volume service."""
    __tablename__ = 'volume_id_mappings'
    __table_args__ = ()
    id = Column(Integer, primary_key=True, nullable=False, autoincrement=True)
    uuid = Column(String(36), nullable=False)


class SnapshotIdMapping(BASE, NovaBase, models.SoftDeleteMixin):
    """Compatibility layer for the EC2 snapshot service."""
    __tablename__ = 'snapshot_id_mappings'
    __table_args__ = ()
    id = Column(Integer, primary_key=True, nullable=False, autoincrement=True)
    uuid = Column(String(36), nullable=False)


class InstanceFault(BASE, NovaBase, models.SoftDeleteMixin):
    __tablename__ = 'instance_faults'
    __table_args__ = (
        Index('instance_faults_host_idx', 'host'),
        Index('instance_faults_instance_uuid_deleted_created_at_idx',
              'instance_uuid', 'deleted', 'created_at')
    )

    id = Column(Integer, primary_key=True, nullable=False)
    instance_uuid = Column(String(36),
                           ForeignKey('instances.uuid'))
    code = Column(Integer(), nullable=False)
    message = Column(String(255))
    details = Column(MediumText())
    host = Column(String(255))


class InstanceAction(BASE, NovaBase, models.SoftDeleteMixin):
    """Track client actions on an instance.

    The intention is that there will only be one of these per user request.  A
    lookup by (instance_uuid, request_id) should always return a single result.
    """
    __tablename__ = 'instance_actions'
    __table_args__ = (
        Index('instance_uuid_idx', 'instance_uuid'),
        Index('request_id_idx', 'request_id')
    )

    id = Column(Integer, primary_key=True, nullable=False, autoincrement=True)
    action = Column(String(255))
    instance_uuid = Column(String(36),
                           ForeignKey('instances.uuid'))
    request_id = Column(String(255))
    user_id = Column(String(255))
    project_id = Column(String(255))
    start_time = Column(DateTime, default=timeutils.utcnow)
    finish_time = Column(DateTime)
    message = Column(String(255))


class InstanceActionEvent(BASE, NovaBase, models.SoftDeleteMixin):
    """Track events that occur during an InstanceAction."""
    __tablename__ = 'instance_actions_events'
    __table_args__ = ()

    id = Column(Integer, primary_key=True, nullable=False, autoincrement=True)
    event = Column(String(255))
    action_id = Column(Integer, ForeignKey('instance_actions.id'))
    start_time = Column(DateTime, default=timeutils.utcnow)
    finish_time = Column(DateTime)
    result = Column(String(255))
    traceback = Column(Text)
    host = Column(String(255))
    details = Column(Text)


class InstanceIdMapping(BASE, NovaBase, models.SoftDeleteMixin):
    """Compatibility layer for the EC2 instance service."""
    __tablename__ = 'instance_id_mappings'
    __table_args__ = (
        Index('ix_instance_id_mappings_uuid', 'uuid'),
    )
    id = Column(Integer, primary_key=True, nullable=False, autoincrement=True)
    uuid = Column(String(36), nullable=False)


class TaskLog(BASE, NovaBase, models.SoftDeleteMixin):
    """Audit log for background periodic tasks."""
    __tablename__ = 'task_log'
    __table_args__ = (
        schema.UniqueConstraint(
            'task_name', 'host', 'period_beginning', 'period_ending',
            name="uniq_task_log0task_name0host0period_beginning0period_ending"
        ),
        Index('ix_task_log_period_beginning', 'period_beginning'),
        Index('ix_task_log_host', 'host'),
        Index('ix_task_log_period_ending', 'period_ending'),
    )
    id = Column(Integer, primary_key=True, nullable=False, autoincrement=True)
    task_name = Column(String(255), nullable=False)
    state = Column(String(255), nullable=False)
    host = Column(String(255), nullable=False)
    period_beginning = Column(DateTime, default=timeutils.utcnow,
                              nullable=False)
    period_ending = Column(DateTime, default=timeutils.utcnow,
                           nullable=False)
    message = Column(String(255), nullable=False)
    task_items = Column(Integer(), default=0)
    errors = Column(Integer(), default=0)


class InstanceGroupMember(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents the members for an instance group."""
    __tablename__ = 'instance_group_member'
    __table_args__ = (
        Index('instance_group_member_instance_idx', 'instance_id'),
    )
    id = Column(Integer, primary_key=True, nullable=False)
    instance_id = Column(String(255))
    group_id = Column(Integer, ForeignKey('instance_groups.id'),
                      nullable=False)


class InstanceGroupPolicy(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents the policy type for an instance group."""
    __tablename__ = 'instance_group_policy'
    __table_args__ = (
        Index('instance_group_policy_policy_idx', 'policy'),
    )
    id = Column(Integer, primary_key=True, nullable=False)
    policy = Column(String(255))
    group_id = Column(Integer, ForeignKey('instance_groups.id'),
                      nullable=False)


class InstanceGroup(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents an instance group.

    A group will maintain a collection of instances and the relationship
    between them.
    """

    __tablename__ = 'instance_groups'
    __table_args__ = (
        schema.UniqueConstraint("uuid", "deleted",
                                 name="uniq_instance_groups0uuid0deleted"),
    )

    id = Column(Integer, primary_key=True, autoincrement=True)
    user_id = Column(String(255))
    project_id = Column(String(255))
    uuid = Column(String(36), nullable=False)
    name = Column(String(255))
    _policies = orm.relationship(InstanceGroupPolicy, primaryjoin='and_('
        'InstanceGroup.id == InstanceGroupPolicy.group_id,'
        'InstanceGroupPolicy.deleted == 0,'
        'InstanceGroup.deleted == 0)')
    _members = orm.relationship(InstanceGroupMember, primaryjoin='and_('
        'InstanceGroup.id == InstanceGroupMember.group_id,'
        'InstanceGroupMember.deleted == 0,'
        'InstanceGroup.deleted == 0)')

    @property
    def policies(self):
        return [p.policy for p in self._policies]

    @property
    def members(self):
        return [m.instance_id for m in self._members]


class PciDevice(BASE, NovaBase, models.SoftDeleteMixin):
    """Represents a PCI host device that can be passed through to instances.
    """
    __tablename__ = 'pci_devices'
    __table_args__ = (
        Index('ix_pci_devices_compute_node_id_deleted',
              'compute_node_id', 'deleted'),
        Index('ix_pci_devices_instance_uuid_deleted',
              'instance_uuid', 'deleted'),
        Index('ix_pci_devices_compute_node_id_parent_addr_deleted',
              'compute_node_id', 'parent_addr', 'deleted'),
        schema.UniqueConstraint(
            "compute_node_id", "address", "deleted",
            name="uniq_pci_devices0compute_node_id0address0deleted")
    )
    id = Column(Integer, primary_key=True)

    compute_node_id = Column(Integer, ForeignKey('compute_nodes.id'),
                             nullable=False)

    # physical address of device domain:bus:slot.func (0000:09:01.1)
    address = Column(String(12), nullable=False)

    vendor_id = Column(String(4), nullable=False)
    product_id = Column(String(4), nullable=False)
    dev_type = Column(String(8), nullable=False)
    dev_id = Column(String(255))

    # label is abstract device name, that is used to unify devices with the
    # same functionality with different addresses or host.
    label = Column(String(255), nullable=False)

    status = Column(String(36), nullable=False)
    # the request_id is used to identify a device that is allocated for a
    # particular request
    request_id = Column(String(36), nullable=True)

    extra_info = Column(Text)

    instance_uuid = Column(String(36))

    numa_node = Column(Integer, nullable=True)

    parent_addr = Column(String(12), nullable=True)
    instance = orm.relationship(Instance, backref="pci_devices",
                            foreign_keys=instance_uuid,
                            primaryjoin='and_('
                            'PciDevice.instance_uuid == Instance.uuid,'
                            'PciDevice.deleted == 0)')


class Tag(BASE, models.ModelBase):
    """Represents the tag for a resource."""

    __tablename__ = "tags"
    __table_args__ = (
        Index('tags_tag_idx', 'tag'),
    )
    resource_id = Column(String(36), primary_key=True, nullable=False)
    tag = Column(Unicode(80), primary_key=True, nullable=False)

    instance = orm.relationship(
        "Instance",
        backref='tags',
        primaryjoin='and_(Tag.resource_id == Instance.uuid,'
                    'Instance.deleted == 0)',
        foreign_keys=resource_id
    )


class ResourceProvider(BASE, models.ModelBase):
    """Represents a mapping to a providers of resources."""

    __tablename__ = "resource_providers"
    __table_args__ = (
        Index('resource_providers_uuid_idx', 'uuid'),
        schema.UniqueConstraint('uuid',
            name='uniq_resource_providers0uuid'),
        Index('resource_providers_name_idx', 'name'),
        schema.UniqueConstraint('name',
            name='uniq_resource_providers0name')
    )

    id = Column(Integer, primary_key=True, nullable=False)
    uuid = Column(String(36), nullable=False)
    name = Column(Unicode(200), nullable=True)
    generation = Column(Integer, default=0)
    can_host = Column(Integer, default=0)


class Inventory(BASE, models.ModelBase):
    """Represents a quantity of available resource."""

    __tablename__ = "inventories"
    __table_args__ = (
        Index('inventories_resource_provider_id_idx',
              'resource_provider_id'),
        Index('inventories_resource_class_id_idx',
              'resource_class_id'),
        Index('inventories_resource_provider_resource_class_idx',
              'resource_provider_id', 'resource_class_id'),
        schema.UniqueConstraint('resource_provider_id', 'resource_class_id',
            name='uniq_inventories0resource_provider_resource_class')
    )

    id = Column(Integer, primary_key=True, nullable=False)
    resource_provider_id = Column(Integer, nullable=False)
    resource_class_id = Column(Integer, nullable=False)
    total = Column(Integer, nullable=False)
    reserved = Column(Integer, nullable=False)
    min_unit = Column(Integer, nullable=False)
    max_unit = Column(Integer, nullable=False)
    step_size = Column(Integer, nullable=False)
    allocation_ratio = Column(Float, nullable=False)
    resource_provider = orm.relationship(
        "ResourceProvider",
        primaryjoin=('and_(Inventory.resource_provider_id == '
                     'ResourceProvider.id)'),
        foreign_keys=resource_provider_id)


class Allocation(BASE, models.ModelBase):
    """A use of inventory."""

    __tablename__ = "allocations"
    __table_args__ = (
        Index('allocations_resource_provider_class_used_idx',
              'resource_provider_id', 'resource_class_id',
              'used'),
        Index('allocations_resource_class_id_idx',
              'resource_class_id'),
        Index('allocations_consumer_id_idx', 'consumer_id')
    )

    id = Column(Integer, primary_key=True, nullable=False)
    resource_provider_id = Column(Integer, nullable=False)
    consumer_id = Column(String(36), nullable=False)
    resource_class_id = Column(Integer, nullable=False)
    used = Column(Integer, nullable=False)


class ResourceProviderAggregate(BASE, models.ModelBase):
    """Assocate a resource provider with an aggregate."""

    __tablename__ = 'resource_provider_aggregates'
    __table_args__ = (
        Index('resource_provider_aggregates_aggregate_id_idx',
              'aggregate_id'),
    )

    resource_provider_id = Column(Integer, primary_key=True, nullable=False)
    aggregate_id = Column(Integer, primary_key=True, nullable=False)