[Gluster-devel] Feature page on Volume lifecycle extensions (aka Hooks)

[krish]

On 08/27/2012 01:42 PM, Deepak C Shetty wrote:
> On 08/24/2012 11:56 AM, Krishnan Parthasarathi wrote:
>> Hi list,
>>
>> The following wiki page provides detailed information on "Volume life 
>> cycle extensions"
>> or more fondly referred to as Hooks. Hooks are scripts/executables 
>> that would
>> be run on the trigger of events like volume-start, volume-stop, etc. 
>> This allows admin
>> to customise her volume 'deployment' work-flow. Of course it is not 
>> arbitrarily expressive/powerful
>> yet.
>>
>> http://www.gluster.org/community/documentation/index.php/Features/Hooks
>
> This (conceptually) is similar to hooks provided by oVirt/VDSM. I have 
> a naive Q tho'
> How to enable/disable a hook for a particular volume  ? Is it that if 
> i don't set any key=value for a particular volume, the hook won't come 
> into action. In other words hooks will use key=value to determine what 
> they need to do ?
Scripts whose name begin with 'S' are enabled and anything else would be 
disabled
I have updated the wiki with the answer to your question. Thanks for asking!
(See 
http://www.gluster.org/community/documentation/index.php/Features/Hooks#Detailed_Description)

>> Hope to hear comments on how we should take this feature forward. I 
>> am thinking we
>> should someday have a community repository of custom workflows built 
>> around Hooks
>> that we can recommend each other.
>
> Could you provide some real world examples where using hook in gluster 
> env would help ?
One example I can think of is to expose certain volumes (identified by 
the storage admin) via CIFS/FTP/HTTP,
by just "letting the respective services know" about the new started 
volume (say exposed via a fuse mount).

In short, any system wide action that is outside of the scope of 
glusterd that one can associate closely with the
events defined in the Hooks system is an example.

thanks,
krish