[Openstack] Running code on instance start/terminate

Leander Bessa leanderbb at gmail.com
Fri Mar 30 09:20:24 UTC 2012


Here's my code, i'm using pika library instead of amqplib.

import pika
>
> connection = pika.BlockingConnection(pika.ConnectionParameters(host=
> 'localhost',credentials=pika.PlainCredentials(username='guest',password=
> 'nova')))
>
> channel = connection.channel()
>
> print ' [*] Waiting for messages. To exit press CTRL+C'
>
>
> def callback(ch, method, properties, body):
>
>   print " [x] Method:",method
>
>   print "     Properties:", properties
>
>   print "     Received %r" % (body,)
>
>
>
> result = channel.queue_declare(exclusive=True)
>
> queue_name = result.method.queue
>
>
> channel.exchange_declare(exchange='nova',type='topic')
>
> channel.queue_bind(exchange='nova',queue=queue_name, routing_key =
> 'notifications.#')
>
> channel.queue_bind(exchange='nova',queue=queue_name, routing_key =
> 'compute.#')
>
> channel.basic_consume(callback,
>
>                       queue=queue_name,
>
>                       no_ack=True)
>
>
> channel.start_consuming()
>

On Thu, Mar 29, 2012 at 6:50 PM, Rogério Vinhal Nunes
<rogervn at dcc.ufmg.br>wrote:

> Actually, I'm having problems in a much simpler layer. I've done the
> following code thinking that I would start from there to find info:
>
> ---------------------
> conn = amqp.Connection(host="localhost:5672", userid="guest",
> password="guest", virtual_host="/", insist=False)
> chan = conn.channel()
> chan.queue_bind(queue="compute", exchange="nova", routing_key="
> notifications.info")
>
> def recv_callback(msg):
>     print 'Received: ' + msg.body + ' from channel #' +
> str(msg.channel.channel_id)
>
> chan.basic_consume(queue='compute', no_ack=True, callback=recv_callback,
> consumer_tag="testtag")
> while True:
>     chan.wait()
> chan.basic_cancel("testtag")
>
>
> chan.close()
> conn.close()
> ---------------------
>
> But I get no messages at all. The script just stays still. I've added
> "--notification_driver=nova.notifier.rabbit_notifier" to nova.conf also.
>
> Em 28 de março de 2012 18:46, Sandy Walsh <sandy.walsh at rackspace.com>escreveu:
>
> Look at
>> https://github.com/rackspace/stacktach/blob/master/worker.py
>> (ignore the _process() call, just look at how the queue listeners are
>> set up)
>>
>> my worker_conf.py looks something like
>> DEPLOYMENTS = [
>>    dict(
>>        tenant_id=1,
>>        url='http://stacktach.example.com',
>>        rabbit_host="10.0.0.1",
>>        rabbit_port=5672,
>>        rabbit_userid="nova-staging",
>>        rabbit_password="password",
>>        rabbit_virtual_host="staging"),
>>    dict(
>>        tenant_id=2,
>>        url='http://stacktach.example.com',
>>        rabbit_host="10.99.0.1",
>>        rabbit_port=5672,
>>        rabbit_userid="nova",
>>        rabbit_password="password",
>>        rabbit_virtual_host="production"),
>>   ]
>>
>>
>> Or the queue listeners in
>> https://github.com/Cerberus98/yagi
>>
>> Hope it helps!
>> -Sandy
>>
>>
>> On 03/28/2012 05:27 PM, Leander Bessa wrote:
>> >>From what i have figured out so far, the exchange queue is "nova" and
>> > the routing key in your case is "notifications.info
>> > <http://notifications.info>".
>> >
>> > On Wed, Mar 28, 2012 at 9:05 PM, Rogério Vinhal Nunes
>> > <rogervn at dcc.ufmg.br <mailto:rogervn at dcc.ufmg.br>> wrote:
>> >
>> >     I'm trying to find out information to make an application that
>> >     consumes the compute info, but I'm having some trouble. Is there a
>> >     better documentation I could follow and the precise details of the
>> >     queue/exchange/routing_key needed to take information at the end of
>> >     each run-instance and terminate-instance?
>> >
>> >     Also, I'm using amqplib and I saw that Openstack uses an internal
>> >     library named Carrot that uses amqplib. Would it be better to use it
>> >     instead?
>> >
>> >     Em 27 de março de 2012 12:42, Sandy Walsh <
>> sandy.walsh at rackspace.com
>> >     <mailto:sandy.walsh at rackspace.com>> escreveu:
>> >
>> >         I believe '.exists' is sent via a periodic update in
>> >         compute.manager.
>> >
>> >
>> >
>> >         On 03/27/2012 12:08 PM, Leander Bessa wrote:
>> >         > Hello,
>> >         >
>> >         > I've been following this topic and i've been trying to
>> receive the
>> >         > notifications directly from rabbitmq with python+pika. So i
>> far
>> >         > i've managed to receive the start/terminate events and
>> >         everything in
>> >         > between. What i am unable to find though is the topic
>> regarding
>> >         > _compute.instance.exists_
>> >         > from http://wiki.openstack.org/SystemUsageData. Does this
>> even
>> >         exist, or
>> >         > is there some extra configuration required with nova?
>> >         >
>> >         > Regards,
>> >         >
>> >         > Leander
>> >         >
>> >         > On Mon, Mar 26, 2012 at 4:54 PM, Russell Bryant
>> >         <rbryant at redhat.com <mailto:rbryant at redhat.com>
>> >         > <mailto:rbryant at redhat.com <mailto:rbryant at redhat.com>>>
>> wrote:
>> >         >
>> >         >     -----BEGIN PGP SIGNED MESSAGE-----
>> >         >     Hash: SHA1
>> >         >
>> >         >     On 03/26/2012 11:48 AM, Russell Bryant wrote:
>> >         >     > On 03/26/2012 10:15 AM, Rogério Vinhal Nunes wrote:
>> >         >     >> Hello,
>> >         >     >>
>> >         >     >> I'm developing a application to work along with
>> >         openstack. My
>> >         >     >> application needs to keep track of all instances being
>> >         started
>> >         >     >> or terminated such as feeding it information about the
>> >         location,
>> >         >     >> status and other information about launched and
>> terminated
>> >         >     >> instances. The current version makes timed queries to
>> >         OpenStack
>> >         >     >> database, but this is showing to be a little consuming
>> and
>> >         >     >> inefficient, so I would like to add a portion of code
>> >         to make
>> >         >     >> OpenStack actively feed my application information
>> >         whenever an
>> >         >     >> instance changes its status or location.
>> >         >     >>
>> >         >     >> What is the least intrusive way to do that? It would be
>> >         very nice
>> >         >     >> if OpenStack provided a way to run code on these
>> situations
>> >         >     >> without actually changing any code, such as defining a
>> >         directory
>> >         >     >> of scripts to run in every instance status change.
>> >         >     >
>> >         >     > Check out the notifications system:
>> >         >     >
>> >         >     > http://wiki.openstack.org/NotificationSystem
>> >         >     >
>> >         >
>> >         >     That wasn't the page I thought it was ... I meant:
>> >         >
>> >         >        http://wiki.openstack.org/SystemUsageData
>> >         >
>> >         >     You can consume these events via AMQP if you configure
>> >         nova to use the
>> >         >     rabbit notifier.
>> >         >
>> >         >     - --
>> >         >     Russell Bryant
>> >         >     -----BEGIN PGP SIGNATURE-----
>> >         >     Version: GnuPG v1.4.12 (GNU/Linux)
>> >         >     Comment: Using GnuPG with Mozilla -
>> >         http://enigmail.mozdev.org/
>> >         >
>> >         >
>> >         iEYEARECAAYFAk9wkSgACgkQFg9ft4s9SAYFuACfUu23qtxiH6WLCJNyd9gBf8i1
>> >         >     FwQAnifjwWkFHYxo+KhYt8TAWEzTaMYZ
>> >         >     =UWlH
>> >         >     -----END PGP SIGNATURE-----
>> >         >
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