Synnefo

#!/usr/bin/env python

# -*- coding: utf-8 -*-

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"""Business logic for reconciliation

Reconcile the contents of the DB with the actual state of the

Ganeti backend.

Let D be the set of VMs in the DB, G the set of VMs in Ganeti.

RULES:

    R1. Stale servers in DB:

            For any v in D but not in G:

            Set deleted=True.

    R2. Orphan instances in Ganet:

            For any v in G with deleted=True in D:

            Issue OP_INSTANCE_DESTROY.

    R3. Unsynced operstate:

            For any v whose operating state differs between G and V:

            Set the operating state in D based on the state in G.

In the code, D, G are Python dicts mapping instance ids to operating state.

For D, the operating state is chosen from VirtualMachine.OPER_STATES.

For G, the operating state is True if the machine is up, False otherwise.

"""

import logging

import sys

from django.core.management import setup_environ

try:

    from synnefo import settings

except ImportError:

    raise Exception("Cannot import settings, make sure PYTHONPATH contains "

                    "the parent directory of the Synnefo Django project.")

setup_environ(settings)

from synnefo.db.models import VirtualMachine

from synnefo.util.dictconfig import dictConfig

from synnefo.util.rapi import GanetiRapiClient

log = logging.getLogger()

def stale_servers_in_db(D, G):

    idD = set(D.keys())

    idG = set(G.keys())

    return idD - idG

def orphan_instances_in_ganeti(D, G):

    idD = set(D.keys())

    idG = set(G.keys())

    return idG - idD

def unsynced_operstate(D, G):

    unsynced = set()

    idD = set(D.keys())

    idG = set(G.keys())

    for i in idD & idG:

        if (G[i] and D[i] != 'STARTED' or

            not G[i] and D[i] not in ('BUILD', 'ERROR', 'STOPPED')):

            unsynced.add((i, D[i], G[i]))

    return unsynced

def get_servers_from_db():

    vms = VirtualMachine.objects.filter(deleted=False)

    return dict(map(lambda x: (x.id, x.operstate), vms))

def get_instances_from_ganeti():

    rapi = GanetiRapiClient(*settings.GANETI_CLUSTER_INFO)

    ganeti_instances = rapi.GetInstances(bulk=True)

    snf_instances = {}

    prefix = settings.BACKEND_PREFIX_ID

    for i in ganeti_instances:

        if i['name'].startswith(prefix):

            try:

                id = int(i['name'].split(prefix)[1])

            except Exception:

                log.error("Ignoring instance with malformed name %s",

                              i['name'])

                continue

            if id in snf_instances:

                log.error("Ignoring instance with duplicate Synnefo id %s",

                    i['name'])

                continue

            snf_instances[id] = i['oper_state']

    return snf_instances

# Only for testing this module individually

def main():

    print get_instances_from_ganeti()

if __name__ == "__main__":

    sys.exit(main())