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On 7/26/2017 11:34 AM, Matt Riedemann wrote:
> On 7/26/2017 11:23 AM, Matt Riedemann wrote:
>>
>> Given this, what else do you need? Please be clear about what your use 
>> case is and how it is not solved using the 2.53 microversion. There 
>> may need to be changes to the CLI but let's separate that concern from 
>> the REST API changes.
> 
> I think your issue might be with these commands which use the 
> hypervisors.search python API binding in novaclient:
> 
> 1. nova host-meta # Set or Delete metadata on all instances of a host.
> 2. nova host-evacuate # Evacuate all instances from failed host
> 3. nova host-evacuate-live # Live migrate all instances of the specified 
> host (we should really rename this command since it doesn't 'evacuate' 
> it live migrates)
> 4. nova host-servers-migrate # Cold migrate all instances off the 
> specified host
> 
> The risk with any of these is on the hostname match hitting more 
> hypervisors than you wanted or expected. So if I have 10 computes in a 
> London region in data center 1 named something like 
> london.dc1.compute1.foo.bar, london.dc1.compute2.foo.bar, etc, and I do:
> 
> nova host-evacuate london.dc1
> 
> It's going to match all of those and evacuate instances from all of 
> those dc1 computes in my london region at once, obviously probably not 
> something you want, unless dc1 is being attacked by Harry Potter fans 
> and you need to get those instances to another data center.
> 
> The solution here is you specify the fully qualified domain name for the 
> host you want to evacuate:
> 
> nova host-evacuate london.dc1.compute1.foo.bar
> 
> Right? What am I missing here?
> 
> If you wanted to change the CLI to be more strict, we could do that by 
> just adding a --strict_hostname option or something and fail if we get 
> back more than one host, as a way to guard the operator from making a 
> mistake.
> 
> But none of this sounds like changes that need to be done in the REST 
> API, and arguably isn't a bug in the CLI either.
> 

Also, FYI in case you haven't read this:

http://www.danplanet.com/blog/2016/03/03/evacuate-in-nova-one-command-to-confuse-us-all/

-- 

Thanks,

Matt