[jboss-as7-dev] Graceful Shutdown

[David M. Lloyd]

The idea is that existing permit holders (which includes already-running 
requests, already-open transactions, etc.) can still get new permits, 
but those who do not already have a transaction running or open sessions 
or whatever cannot and should be redirected to another node.

On 09/16/2011 09:12 AM, Scott Marlow wrote:
> Is this a fail-fast design? Or should all currently running user
> requests succeed? If new transactions cannot be started, I would think
> that means some running user requests will fail.
>
>
> On 09/13/2011 10:31 AM, David M. Lloyd wrote:
>> We've worked out the rough outline of how graceful shutdown will work in
>> AS7.
>>
>> The process of graceful shutdown actually is reflected by a number of
>> states:
>>
>> 1. Running - all services acting normally
>> 2. Suspending - services refuse new "permits" (see below), existing
>> permits are allowed to be retained (and threads running under such a
>> permit may still acquire new permits)
>> 3. Suspended - no permits are present and none may be issued
>> 4. Shutting Down - our existing server stop process
>>
>> The following transitions are allowed:
>>
>> 1. Running → Suspending: Transition occurs at user request (to suspend
>> or gracefully shut down).
>> 2. Suspending → Suspended: Transition occurs when all permits are
>> cleared.
>> 3. Suspending → Running: Transition occurs at user request (to exit
>> suspend mode or cancel graceful shutdown before it completes).
>> 4. Suspended → Running: Transition occurs at user request (to exit
>> suspend mode).
>> 5. Suspended → Shutting Down: Transition occurs automatically (if a
>> graceful shutdown was requested) or at user request (if a shut down
>> request of any kind is entered in the Suspended state).
>> 6. Running → Shutting Down: Transition occurs at user request (to shut
>> down the server "un-gracefully").
>>
>> These "permits" are issued by the "Shutdown Manager", whose job is to
>> manage these states. They are issued corresponding to the following
>> events:
>>
>> 1. The invocation of an EJB method
>> 2. The creation of a web session
>> 3. A creation of a transaction
>> 4. Probably some situations involving HQ and/or JCA
>>
>> When a permit cannot be issued due to the server shutting down, a
>> standard exception message should be produced so that the user can see a
>> familiar error message regardless of what mechanism is used to access
>> the server.
>>
>


-- 
- DML