[Openstack-operators] Small openstack (part 2), distributed glance

Michael Dorman mdorman at godaddy.com
Wed Jan 21 17:20:26 UTC 2015

This is great info, George.

Could you explain the 3x snapshot transport under the traditional Glance 
setup, please?

I understand that you have compute —> glance, and glance —> swift.  But 
what’s the third transfer?


On 1/21/15, 10:36 AM, "George Shuklin" <george.shuklin at gmail.com> wrote:

>Ok, news so far:
>It works like a magic. Nova have option
>And I do not need to cheat with endpoint resolving (my initial plan was 
>to resolve glance endpoint to with /etc/hosts magic). Normal 
>glance-api reply to external clients requests 
>(image-create/download/list/etc), and local glance-apis (per compute) 
>are used to connect to swift.
>Glance registry works in normal mode (only on 'official' api servers).
>I don't see any reason why we should centralize all traffic to swift 
>through special dedicated servers, investing in fast CPU and 10G links.
>With that solution CPU load on glance-api is distributed evenly on all 
>compute nodes, and overall snapshot traffic (on ports) was cut down 3 
>Why I didn't thought about this earlier?
>On 01/16/2015 12:20 AM, George Shuklin wrote:
>> Hello everyone.
>> One more thing in the light of small openstack.
>> I really dislike tripple network load caused by current glance 
>> snapshot operations. When compute do snapshot, it playing with files 
>> locally, than it sends them to glance-api, and (if glance API is 
>> linked to swift), glance sends them to swift. Basically, for each 
>> 100Gb disk there is 300Gb on network operations. It is specially 
>> painful for glance-api, which need to get more CPU and network 
>> bandwidth than we want to spend on it.
>> So idea: put glance-api on each compute node without cache.
>> To help compute to go to the proper glance, endpoint points to fqdn, 
>> and on each compute that fqdn is pointing to localhost (where 
>> glance-api is live). Plus normal glance-api on API/controller node to 
>> serve dashboard/api clients.
>> I didn't test it yet.
>> Any ideas on possible problems/bottlenecks? And how many 
>> glance-registry I need for this?
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