Open Stack

I have some questions at the html which as follows:
	http://docs.openstack.org/admin-guide-cloud/content/section_telemetry-cetral-compute-agent-ha.html
At this html, is "Without the backend_url option being set only one instance of both the central and compute agent service is able to run and function correctly." right?

There are two node at my openstack environment: 
	Compute node: installed ceilometer-agent-compute and ceilometer-agent-central
	Controller node: installed ceilometer-agent-compute 、ceilometer-agent-central and other services.
Without the backend_url option being set, running ceilometer-agent-central at compute node and controller node, they can work correctly.
___________________________________________________
[root at controller ceilometer(keystone_admin)]# ceilometer sample-list -m storage.containers.objects | head -19
+------------------------------------------------+----------------------------+-------+--------+--------+---------------------+
| Resource ID                                    | Name                       | Type  | Volume | Unit   | Timestamp          |
+------------------------------------------------+----------------------------+-------+--------+--------+---------------------+
| ba28a506cfd344c383fcbc3540559222/jick          | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:56:34 |
| ba28a506cfd344c383fcbc3540559222/wx            | storage.containers.objects | gauge | 1.0    | object | 2015-03-18T14:56:34 |
| ba28a506cfd344c383fcbc3540559222/volumebackups | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:56:34 |
| cd84533ff083463ab18b1dc15236732b/glance        | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:56:34 |
| ba28a506cfd344c383fcbc3540559222/jick          | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:56:31 |
| ba28a506cfd344c383fcbc3540559222/wx            | storage.containers.objects | gauge | 1.0    | object | 2015-03-18T14:56:31 |
| ba28a506cfd344c383fcbc3540559222/volumebackups | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:56:31 |
| cd84533ff083463ab18b1dc15236732b/glance        | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:56:31 |
| ba28a506cfd344c383fcbc3540559222/jick          | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:46:41 |
| cd84533ff083463ab18b1dc15236732b/glance        | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:46:41 |
| ba28a506cfd344c383fcbc3540559222/wx            | storage.containers.objects | gauge | 1.0    | object | 2015-03-18T14:46:41 |
| ba28a506cfd344c383fcbc3540559222/volumebackups | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:46:41 |
| cd84533ff083463ab18b1dc15236732b/glance        | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:46:32 |
| ba28a506cfd344c383fcbc3540559222/wx            | storage.containers.objects | gauge | 1.0    | object | 2015-03-18T14:46:32 |
| ba28a506cfd344c383fcbc3540559222/volumebackups | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:46:32 |
| ba28a506cfd344c383fcbc3540559222/jick          | storage.containers.objects | gauge | 0.0    | object | 2015-03-18T14:46:32 |
_________________________________________________

There are 4 storage.containers.objects, the ceilometer-agent-central of compute node can get 4 samples,the ceilomter-agent-central of controller node can get 4 samples too.
Is it right?

-----邮件原件-----
发件人: Chris Dent [mailto:chdent at redhat.com]
发送时间: 2015年3月11日 21:08
收件人: Pan, Fengyun/潘 风云
抄送: Vijaya Bhaskar; openstack
主题: Re: 答复: [Openstack] Ceilometer high availability in active-active

On Wed, 11 Mar 2015, Pan, Fengyun wrote:

> We kown that:
> backend_url',
>               default=None,
>               help='The backend URL to use for distributed coordination. If '
>                    'left empty, per-deployment central agent and per-host '
>                    'compute agent won\'t do workload '
>                    'partitioning and will only function correctly if a '
>                    'single instance of that service is running.'), But 
> how to set the ‘backend_url’?

This appears to be an oversight in the documentation. The main starting point is here:

    http://docs.openstack.org/admin-guide-cloud/content/section_telemetry-cetral-compute-agent-ha.html

but nothing there nor what it links to actually says what should go as the value of the setting. It's entirely dependent on the backend being used and how that backend is being configured. Each of the tooz drivers has some information on some of the options, but again, it is not fully documented yet.

For reference, what I use in my own testing is redis as follows:

    redis://localhost:6379

This uses a single redis server, so introduces another single point of failure. It's possible to use sentinel to improve upon this situation:

    http://docs.openstack.org/developer/tooz/developers.html#redis

The other drivers work in similar ways with their own unique arguments.

I'm sorry I'm not able to point to more complete information but I can say that it is in the process of being improved.

--
Chris Dent tw:@anticdent freenode:cdent
https://tank.peermore.com/tanks/cdent