Synnefo

#!/usr/bin/env python

#

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

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"""Ganeti hooks for Synnefo

These are the individual Ganeti hooks for Synnefo.

"""

import sys

import os

import subprocess

import time

import json

import socket

import logging

from amqplib import client_0_8 as amqp

try:

    conf_dir = os.environ["SYNNEFO_CONFIG_DIR"]

    import config

    settings = config.load(conf_dir)

except KeyError:

    import synnefo.settings as settings

def mac2eui64(mac, prefixstr):

    process = subprocess.Popen(["mac2eui64", mac, prefixstr],

                                stdout=subprocess.PIPE)

    return process.stdout.read().rstrip()

def ganeti_net_status(logger, environ):

    """Produce notifications of type 'Ganeti-net-status'

    Process all GANETI_INSTANCE_NICx_y environment variables,

    where x is the NIC index, starting at 0,

    and y is one of "MAC", "IP", "BRIDGE".

    The result is returned as a single notification message

    of type 'ganeti-net-status', detailing the NIC configuration

    of a Ganeti instance.

    """

    nics = {}

    key_to_attr = { 'IP': 'ip', 'MAC': 'mac', 'BRIDGE': 'link' }

    for env in environ.keys():

        if env.startswith("GANETI_INSTANCE_NIC"):

            s = env.replace("GANETI_INSTANCE_NIC", "").split('_', 1)

            if len(s) == 2 and s[0].isdigit() and s[1] in ('MAC', 'IP', 'BRIDGE'):

                index = int(s[0])

                key = key_to_attr[s[1]]

                if nics.has_key(index):

                    nics[index][key] = environ[env]

                else:

                    nics[index] = { key: environ[env] }

                # IPv6 support:

                #

                # The IPv6 of NIC with index 0 [the public NIC]

                # is derived using an EUI64 scheme.

                if index == 0 and key == 'mac':

                    nics[0]['ipv6'] = mac2eui64(nics[0]['mac'],

                                                settings.PUBLIC_IPV6_PREFIX)

    # Amend notification with firewall settings

    tags = environ.get('GANETI_INSTANCE_TAGS', '')

    for tag in tags.split(' '):

        t = tag.split(':')

        if t[0:2] == ['synnefo', 'network']:

            if len(t) != 4:

                logger.error("Malformed synnefo tag %s", tag)

                continue

            try:

                index = int(t[2])

                nics[index]['firewall'] = t[3]

            except ValueError:

                logger.error("Malformed synnefo tag %s", tag)

            except KeyError:

                logger.error("Found tag %s for non-existent NIC %d",

                             tag, index)

    # Verify our findings are consistent with the Ganeti environment

    indexes = list(nics.keys())

    ganeti_nic_count = int(environ['GANETI_INSTANCE_NIC_COUNT'])

    if len(indexes) != ganeti_nic_count:

        logger.error("I have %d NICs, Ganeti says number of NICs is %d",

            len(indexes), ganeti_nic_count)

        raise Exception("Inconsistent number of NICs in Ganeti environment")

    if indexes != range(0, len(indexes)):

        logger.error("Ganeti NIC indexes are not consecutive starting at zero.");

        logger.error("NIC indexes are: %s. Environment is: %s", indexes, environ)

        raise Exception("Unexpected inconsistency in the Ganeti environment")

    # Construct the notification

    instance = environ['GANETI_INSTANCE_NAME']

    nics_list = []

    for i in indexes:

        nics_list.append(nics[i])

    msg = {

        "type": "ganeti-net-status",

        "instance": instance,

        "nics": nics_list

    }

    return msg

class GanetiHook():

    def __init__(self, logger, environ, instance, prefix):

        self.logger = logger

        self.environ = environ

        self.instance = instance

        self.prefix = prefix

    def on_master(self):

        """Return True if running on the Ganeti master"""

        return socket.getfqdn() == self.environ['GANETI_MASTER']

    def publish_msgs(self, msgs):

        for (msgtype, msg) in msgs:

            routekey = "ganeti.%s.event.%s" % (self.prefix, msgtype)

            self.logger.debug("Pushing message to RabbitMQ: %s (key = %s)",

                json.dumps(msg), routekey)

            msg = amqp.Message(json.dumps(msg))

            msg.properties["delivery_mode"] = 2  # Persistent

            # Retry up to five times to open a channel to RabbitMQ.

            # The hook needs to abort if this count is exceeded, because it

            # runs synchronously with VM creation inside Ganeti, and may only

            # run for a finite amount of time.

            #

            # FIXME: We need a reconciliation mechanism between the DB and

            #        Ganeti, for cases exactly like this.

            conn = None

            sent = False

            retry = 0

            while not sent and retry < 5:

                self.logger.debug("Attempting to publish to RabbitMQ at %s",

                    settings.RABBIT_HOST)

                try:

                    if not conn:

                        conn = amqp.Connection(host=settings.RABBIT_HOST,

                            userid=settings.RABBIT_USERNAME,

                            password=settings.RABBIT_PASSWORD,

                            virtual_host=settings.RABBIT_VHOST)

                        chann = conn.channel()

                        self.logger.debug("Successfully connected to RabbitMQ at %s",

                            settings.RABBIT_HOST)

                    chann.basic_publish(msg,

                        exchange=settings.EXCHANGE_GANETI,

                        routing_key=routekey)

                    sent = True

                    self.logger.debug("Successfully sent message to RabbitMQ")

                except socket.error:

                    conn = False

                    retry += 1

                    self.logger.exception("Publish to RabbitMQ failed, retry=%d in 1s",

                        retry)

                    time.sleep(1)

            if not sent:

                raise Exception("Publish to RabbitMQ failed after %d tries, aborting" % retry)

class PostStartHook(GanetiHook):

    """Post-instance-startup Ganeti Hook.

    Produce notifications to the rest of the Synnefo

    infrastructure in the post-instance-start phase of Ganeti.

    Currently, this list only contains a single message,

    detailing the net configuration of an instance.

    This hook only runs on the Ganeti master.

    """

    def run(self):

        if self.on_master():

            notifs = []

            notifs.append(("net", ganeti_net_status(self.logger, self.environ)))

            self.publish_msgs(notifs)

        return 0

class PostStopHook(GanetiHook):

    def run(self):

        return 0

def main():

    logging.basicConfig(level=logging.DEBUG)

    logger = logging.getLogger("synnefo.ganeti")

    try:

        instance = os.environ['GANETI_INSTANCE_NAME']

        op = os.environ['GANETI_HOOKS_PATH']

        phase = os.environ['GANETI_HOOKS_PHASE']

    except KeyError:

        raise Exception("Environment missing one of: " \

            "GANETI_INSTANCE_NAME, GANETI_HOOKS_PATH, GANETI_HOOKS_PHASE")

    prefix = instance.split('-')[0]

    # FIXME: The hooks should only run for Synnefo instances.

    # Uncomment the following lines for a shared Ganeti deployment.

    # Currently, the following code is commented out because multiple

    # backend prefixes are used in the same Ganeti installation during development.

    #if not instance.startswith(settings.BACKEND_PREFIX_ID):

    #    logger.warning("Ignoring non-Synnefo instance %s", instance)

    #    return 0

    hooks = {

        ("instance-add", "post"): PostStartHook,

        ("instance-start", "post"): PostStartHook,

        ("instance-reboot", "post"): PostStartHook,

        ("instance-stop", "post"): PostStopHook,

        ("instance-modify", "post"): PostStartHook

    }

    try:

        hook = hooks[(op, phase)](logger, os.environ, instance, prefix)

    except KeyError:

        raise Exception("No hook found for operation = '%s', phase = '%s'" % (op, phase))

    return hook.run()

if __name__ == "__main__":

    sys.exit(main())