Nova Nuke: Forcefully removes an instance from the Nova database. Useful for cleaning up instances stuck in an 'error' or 'deleting' state.

nova_nuke.py

#!/usr/bin/env python

#
# nova_nuke.py
#   usage: nova_nuke.py <uuid>
#
# Forcefully removes an instance from the Nova database.
# Useful for destroying instances stuck in an 'error' or 'deleting' state.
#
# Completes the following actions:
#   * Marks the instance as deleted in nova.instances
#   * Disassociates any fixed IPs assigned to the instance (nova-network)
#   * Updates tenant quotas associated with the instance
#
# Because this script relies on Nova calls which are not exposed by the
# public API in order to access the database, this script must be run from
# a Controller or Compute node.
#
# Use with caution.
#

import sys

from nova.db.sqlalchemy import api
from oslo.config import cfg

class FakeAdminContext(object):
    def __init__(self):
        self.is_admin = True
        self.read_deleted = 'no'


def usage():
    print "usage: %s <uuid>" % sys.argv[0]

def delete_instance(context, uuid):
    return api.instance_destroy(context, uuid)

def disassociate_ips(context, instance):
    ips = api.fixed_ip_get_by_instance(context, instance.uuid)

    for ip in ips:
        api.fixed_ip_disassociate(context, ip.address)

    return ips

def update_quotas(context, instance, ips):
    project_id = instance.project_id
    instance_ips = len(ips)

    ram = api.quota_usage_get(context, project_id, 'ram')
    ram.update({'in_use': ram.in_use - instance.memory_mb})
    ram.save()

    cores = api.quota_usage_get(context, project_id, 'cores')
    cores.update({'in_use': cores.in_use - instance.vcpus})
    cores.save()

    fixed_ips = api.quota_usage_get(context, project_id, 'fixed_ips')
    fixed_ips.update({'in_use': fixed_ips.in_use - instance_ips})
    fixed_ips.save()

    instances = api.quota_usage_get(context, project_id, 'instances')
    instances.update({'in_use': instances.in_use - 1})
    instances.save()

def main():
    if len(sys.argv) != 2:
        usage()
        sys.exit(1)

    uuid = sys.argv.pop()

    # Trick the OpenStack APIs into thinking nova is issuing these requests
    cfg.CONF(project='nova')
    context = FakeAdminContext()

    instance = delete_instance(context, uuid)
    ips = disassociate_ips(context, instance)
    update_quotas(context, instance, ips)

    print "Successfully deleted instance %s (%s)" % (instance.hostname, uuid)

if __name__ == '__main__':
    main()