[openstack-dev] [nova] Bug in documentation for host aggregates and availability zones?

Chris Friesen chris.friesen at windriver.com
Wed Mar 18 14:54:38 UTC 2015


I think I've found some bugs around host aggregates in the documentation, 
curious what people think.

The docs at 
contain this:

nova aggregate-create <name> <availability-zone>

     Create a new aggregate named <name> in availability zone 
<availability-zone>. Returns the ID of the newly created aggregate. Hosts can be 
made available to multiple availability zones, but administrators should be 
careful when adding the host to a different host aggregate within the same 
availability zone and pay attention when using the aggregate-set-metadata and 
aggregate-update commands to avoid user confusion when they boot instances in 
different availability zones. An error occurs if you cannot add a particular 
host to an aggregate zone for which it is not intended.

I'm pretty sure that there are multiple errors in there:

1) This command creates a new aggregate that is *exposed as* an availability 
zone.  It doesn't create a new aggregate within an availability zone. [1] 
Because of that the idea of a "different host aggregate within the same 
availability zone" doesn't make any sense.

2) Hosts can be part of multiple host aggregates, they cannot be part of 
multiple availability zones. [2]



[2] See the check in nova.compute.api.AggregateAPI._check_az_for_host()

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