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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