[Engine-devel] Reloadable Configuration - Wiki Page

[Itamar Heim]

On 03/29/2012 11:59 AM, Doron Fediuck wrote:
> On 29/03/12 10:54, Itamar Heim wrote:
>> On 03/29/2012 10:05 AM, Muli Salem wrote:
>>> Thanks for the comments, I updated the wiki page accordingly:
>>> http://www.ovirt.org/wiki/Features/ReloadableConfiguration
>>>
>>> 1. Instead of the new DB column is_reloadable -->   Annotation to ConfigValues.
>>> 2. Found a way to update the Quartz jobs, at least basic issues such as interval size.
>>> 3. The values will be reloaded upon admin's decision to do so - with a new command in the engine-config CLI, since that is where admins make the changes.
>>
>> just wondering - how will the CLI do this at the technical level (via REST API? signal to service, etc.)?
>
> Basically we need a script using the REST sdk to trigger re-configuration
> This script will need the engine's IP so it'll know where to find it.
> The thing is, REST also needs the admin's user and password to run...
>
> We can get it in 2 options:
>
> 1. Store Admin's user+pass in the engine's conf file.
> 2. Use engine-config to fetch the credentials.
>
> Once we have credentials, we can use it with a new script to trigger configuration reload.
> We can also incorporate this script into engine-config so admin won't need to know another
> script, and simply use a 'reload' verb.
>
> I'm not keen on storing the credentials in a conf' file, but (unfortunately) it wouldn't
> be a first time. Any better alternative is welcome (just as patches ;-).

true.

>
> A simple alternative to the whole credentials and IP need,
> is a simple periodic reload, as suggested initially.



>
> /d

isn't there some way to send a process signal or something like that 
(not allowing remote access, but i think it uses the db crednetials from 
a local file anyway, and i don't think running config remotely is a must)

other options:
1. require user to provide user/password (kind of funny for running 
manage-domains utility, but possible
2. use a way on the host to send a signal (change a file, process 
signal, etc.)