On Thu, Jun 12, 2014 at 11:33 AM, Tiago Sousa <tiagu....@gmail.com> wrote:
> Hi, does anyone have documentation on how the extra_specs work? > > There's a bit of a worked example in the Operations Guide. >From http://docs.openstack.org/trunk/openstack-ops/content/scaling.html An advanced use of this general concept allows different instance types to run with different CPU and RAM allocation rations so that high-intensity computing loads and low-intensity development and testing systems can share the same cloud without either starving the high-use systems or wasting resources on low-utilization systems. This works by setting metadata in your host aggregates and matching extra_specs in your instance types. The first step is setting the aggregate metadata keys cpu_allocation_ratio and ram_allocation_ration to a floating-point value. The filter schedulers AggregateCoreFilter and AggregateRamFilter will use those values rather than the global defaults in nova.conf when scheduling to hosts in the aggregate. It is important to be cautious when using this feature, since each host can be in multiple aggregates but should have only one allocation ratio for each resources. It is up to you to avoid putting a host in multiple aggregates that define different values for the same resource. This is the first half of the equation. To get instance types that are guaranteed a particular ratio, you must set theextra_specs in the instance type to the key-value pair you want to match in the aggregate. For example, if you defineextra specs cpu_allocation_ratio to "1.0", then instances of that type will run in aggregates only where the metadata key cpu_allocation_ratio is also defined as "1.0." In practice, it is better to define an additional key-value pair in the aggregate metadata to match on rather than match directly on cpu_allocation_ratio or core_allocation_ratio. This allows better abstraction. For example, by defining a key overcommit and setting a value of "high," "medium," or "low," you could then tune the numeric allocation ratios in the aggregates without also needing to change all instance types relating to them. > I would like to add a serial port to a flavor, and my research pointed me > to the extra_specs but got stuck there. > > > Cheers, > Tiago > > _______________________________________________ > Mailing list: > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > Post to : openstack@lists.openstack.org > Unsubscribe : > http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack > >
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