Open Stack

> One part of the documentation set that we were missing was a guide to how to migrate from ceilometer to a ceilometer/gnocchi combination (which I understand is the ultimate architecture). We would like to migrate the historical data we have stored in ceilometer.
>
> The main line documentation (such as http://docs.openstack.org/liberty/config-reference/content/) does not yet contain details on the Gnocchi configuration so some people may miss this option when following the docs. The gnocchi.xyz has good content but it is not the standard configuration guides. I guess once Gnocchi is into the Big Tent then this sort of integration can occur.
>
> It’s early days yet so we don’t yet have the feeling for running Gnocchi at scale.
>
> Tim

hi,

there isn't an active migration path between Ceilometer's legacy 
database to Gnocchi. it was discussed but given the limited resources we 
have (contributors are welcomed) we just do not have the bandwidth 
currently to build a tool to help port data over.

Gnocchi is not a 1:1 replacement of Ceilometer's old API, it does not 
capture full-fidelity of data and requires defined archive policy rules, 
which makes a migration tool necessary. it is mainly intended to replace 
the 'ceilometer statistics' use case of the old API.

we were hoping to get a reference architecture this cycle but were 
delayed due to resources being pulled to other tasks. currently, the 
best option is to take a look at the devstack plugins for Gnocchi[1] and 
Ceilometer[2] (requires bash knowledge) to get an idea of how they're 
set up to work together in the gate.

as with all new things, it's recommended you test this out first, to 
learn new API[3] and find potential bugs. you can configure the 
Ceilometer collector to write to both existing db and Gnocchi so your 
current usage is not interrupted.

[1] https://github.com/openstack/gnocchi/blob/master/devstack/plugin.sh
[2] https://github.com/openstack/ceilometer/blob/master/devstack/plugin.sh
[3] http://gnocchi.xyz/rest.html

cheers,
-- 
gord