[jboss-as7-dev] problems with deployment overlays and linking

Alexey Loubyansky alexey.loubyansky at redhat.com
Tue Sep 4 10:15:30 EDT 2012 

What would great, if we could specify references a la foreign keys and 
cascade delete at the resource definition level in the model.
That would be tricky in the domain mode across server groups and 
servers. But it has to be done anyway: by a tool or by the controller.

On 09/04/2012 04:04 PM, Brian Stansberry wrote:
> Can you file a JIRA for the kind of cascading behavior you're thinking
> about? I don't see it happening in 7.2, but perhaps 7.3, if it can be
> done in a compatible way. If not, AS 8.
>
> I believe I already filed a JIRA for adding metadata to better describe
> the reference relationships in the model. Cascading behavior would
> depend on that.
>
> On 9/4/12 8:20 AM, Alexey Loubyansky wrote:
>> Another issue in the domain mode is when I need to remove an overlay I
>> should go across all the server groups and check where it is referenced
>> from and clean-up. But again, it's not specific to overlays, when I
>> undeploy an app in the domain mode (depending on the arguments) I have
>> to do the same thing.
>>
>> On 09/04/2012 02:27 PM, Alexey Loubyansky wrote:
>>> That'll help, thanks.
>>>
>>> There is one other issue I can mention (which is not as critical as the
>>> original) which makes linking a bit more complicated in the domain mode.
>>> Standalone works fine.
>>>
>>> The linking in the domain mode is done as
>>>
>>> server-group=sg_name/deployment-overlay=overlay_name/deployment=app.war
>>>
>>> deployment-overlay=overlay_name has to be created explicitly with its
>>> own 'add' (since we don't implicitly create non-existing parent nodes).
>>> So, every time a link is added, we have to perform a check whether the
>>> server-group=sg_name/deployment-overlay=overlay_name part exists. If
>>> not, create it. Then proceed with the actual linking.
>>>
>>> It's doable, of course. But from the tools' side, to compose the final
>>> composite op, it will need to perform some intermediary ops. Of course,
>>> adding the non existing parent can and should be put into the same final
>>> composite op for efficiency.
>>>
>>> This is not the only command which behaves this way. For these commands,
>>> it means:
>>> - the final composite request may differ from one execution to another
>>> depending on the state of the model (not only argument values but actual
>>> requested actions);
>>> - the model checks (or other necessary intermediate ops) are performed
>>> not at the same time with the actual final request (i.e. kind of in a
>>> different transaction) which doesn't guarantee the same state when the
>>> actual request is executed;
>>> - the previous one may affect run-time batches, since every command
>>> added to a batch is translated into a DMR request immediately, not right
>>> before the batch is actually run (which would be safer and which I
>>> should do actually).
>>>
>>> Alexey
>>>
>>>
>>> On 09/04/2012 12:40 AM, Stuart Douglas wrote:
>>>> I will fix this to make it work like the deploy operation. Not sure if I
>>>> will have time to get to it today.
>>>>
>>>> Stuart
>>>>> Alexey Loubyansky <mailto:alexey.loubyansky at redhat.com>
>>>>> 3 September 2012 10:39 PM
>>>>> Sorry for the late reply, I'll cherry-pick it, ok.
>>>>>
>>>>> One issue that I mentioned and still there is that you can't add a new
>>>>> overlay with content in a single composite operation (first the content
>>>>> should be uploaded then its references can be used in the overlay). So,
>>>>> this command still can't be executed as part of a batch.
>>>>>
>>>>> Alexey
>>>>> _______________________________________________
>>>>> jboss-as7-dev mailing list
>>>>> jboss-as7-dev at lists.jboss.org
>>>>> https://lists.jboss.org/mailman/listinfo/jboss-as7-dev
>>>>> Brian Stansberry <mailto:brian.stansberry at redhat.com>
>>>>> 1 September 2012 2:28 AM
>>>>> Do you see value in cherry-picking his patch and adjusting the command
>>>>> first?  The issues you find implementing the command are what led to
>>>>> these changes, so it'd be nice to know your commands work before
>>>>> merging his stuff.
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Alexey Loubyansky <mailto:olubyans at redhat.com>
>>>>> 31 August 2012 8:03 PM
>>>>> Great. Once it's merged I'll adjust the deployment-overlay command and
>>>>> submit a pull request.
>>>>>
>>>>> Thanks,
>>>>> Alexey
>>>>>
>>>>>
>>>>> Stuart Douglas <mailto:stuart.w.douglas at gmail.com>
>>>>> 31 August 2012 1:29 PM
>>>>>
>>>>> I have done up an initial implementation of this here
>>>>> https://github.com/jbossas/jboss-as/pull/2989 .
>>>>>
>>>>>
>>>>> Stuart
>>>>>
>>>>>
>>>>>
>>>>> Brian Stansberry <mailto:brian.stansberry at redhat.com>
>>>>> 24 August 2012 2:08 AM
>>>>> On 8/23/12 3:39 AM, Emanuel Muckenhuber wrote:
>>>>>> On 08/23/2012 01:11 AM, Brian Stansberry wrote:
>>>>>>> Sorry for the slow responses on this thread.
>>>>>>>
>>>>>>> I think we should go with Stuart's approach, particularly if Alexey is
>>>>>>> comfortable that the CLI can support high level commands associated with it.
>>>>>>>
>>>>>> Yeah, i am fine then as well - nevertheless some comments inline :)
>>>>>>
>>>>>
>>>>> Me too. ;)
>>>>>
>>>>>>> On 8/22/12 8:22 AM, Emanuel Muckenhuber wrote:
>>>>>>>> My main concern is regarding the domain mode, since the additional
>>>>>>>> linking does not seem to be necessary to me and just additional steps
>>>>>>>> mgmt clients have to take care of.
>>>>>>>>
>>>>>>>> Whereas the deployment-scanner is a single client for standalone, which
>>>>>>>> is under our control. So i wanted to see if we there is a way we can
>>>>>>>> make this work which also satisfies your use cases.
>>>>>>>>
>>>>>>>> I have two things in mind which i'll try to explain quickly:
>>>>>>>>
>>>>>>>> 1) you still link the overlays as part of the <deployment />, however
>>>>>>>> the deploment-scanner is aware of that and won't remove deployments with
>>>>>>>> overlays until you use a specific invalidation marker.
>>>>>>>>
>>>>>>> This requires that the overlays be controlled by the scanner as well.
>>>>>>> Why? Because we don't persist the model resource for scanner-controlled
>>>>>>> deployments. So if a user linked a non-scanner-controlled overlay to a
>>>>>>> scanner controlled deployment (which seems quite rational if the overlay
>>>>>>> involves some environmental settings that never change), the link
>>>>>>> information will be lost on server reboot.
>>>>>>>
>>>>>> I know, but that's an ancient limitation. I guess we could just start to
>>>>>> persist stuff.
>>>>>>
>>>>>
>>>>> We'd have to persist some association between a deployment and a scanner
>>>>> (e.g. scanner="default" on the deployment element) and then use that to
>>>>> indicate that the server should not auto-deploy on boot but should defer
>>>>> to the scanner to tell it what to do. And then alter the scanner to add
>>>>> logic for it to reconcile the state it sees in the scan directory vs
>>>>> what the model shows.
>>>>>
>>>>> Doable, but a fair bit of work.
>>>>>
>>>>> I considered this before going with the "don't persist" approach. I
>>>>> don't recall though if there was some fundamental problem with it that
>>>>> I'm not remembering, or if it was solely that "don't persist" was doable
>>>>> within the time constraints.
>>>>>
>>>>>>>> 2) use overlay directories - this is more the file based approach, Where
>>>>>>>> we just pick the "deployment.name + suffix" for the overlay. So there
>>>>>>>> would be an automatic overlay/linking done by the deployment-scanner.
>>>>>>>>
>>>>>>> Same issue as 1).
>>>>>>>
>>>>>> Not really. It can automatically recreate the overlays therefore it does
>>>>>> not require persistent information.
>>>>>>
>>>>>
>>>>> It can only recreate the association for overlays that it scans, not
>>>>> ones that were added via CLI/console.
>>>>>
>>>>>>>> 2.1) the overlay directory could be just a link to a virtual file (a
>>>>>>>> shared <deployment-overlay />) [1] - so in this case the overlays are
>>>>>>>> managed by the model and are not linked to the deployment lifecycle.
>>>>>>>>
>>>>>>> I confess I don't understand this. In particular, how does it
>>>>>>> fundamentally differ from what Stuart proposes in terms of how to
>>>>>>> organize the data?
>>>>>>>
>>>>>> Well that is the point. It's basically the same, just that it removes
>>>>>> the requirement for the additional linking in the domain.
>>>>>>
>>>>>
>>>>> Ok, then I still don't understand it. If it solves a problem I'd like to
>>>>> understand. Can you explain further?
>>>>>
>>>>>>>> On 08/22/2012 01:03 AM, Stuart Douglas wrote:
>>>>>>>>> So what are we going to do here? Personally I much prefer the idea of having this stored in the model and linking it to a deployment, so the overlay lifecycle is not tied to that of the deployment.
>>>>>>>>>
>>>>>>>>> Another idea I had is that we could do something like define the overlays at domain level, but then define the links at server group or server level using the same name. basically something like:
>>>>>>>>>
>>>>>>>>> /deployment-overlay=myOverlay/content=WEB-INF/web.xml
>>>>>>>>> /deployment-overlay=myOverlay/content=WEB-INF/ejb-jar.xml
>>>>>>>>>
>>>>>>>>> /server-group=server-group1/deployment-overlay=myOverlay/deployment=test.war
>>>>>>>>> /server-group=server-group1/deployment-overlay=myOverlay/deployment=*.war
>>>>>>>>>
>>>>>>>>> For standalone they would just be combined, similar to what I had below:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> /deployment-overlay=myOverlay/content=WEB-INF/web.xml
>>>>>>>>> /deployment-overlay=myOverlay/content=WEB-INF/ejb-jar.xml
>>>>>>>>> /deployment-overlay=myOverlay/deployment=test.war
>>>>>>>>> /deployment-overlay=myOverlay/deployment=*.war
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Stuart
>>>>>>>>>
>>>>>>>>> On 17/08/2012, at 11:03 PM, Emanuel Muckenhuber<emuckenh at redhat.com>  wrote:
>>>>>>>>>
>>>>>>>>>> On 08/17/2012 02:52 AM, Stuart Douglas wrote:
>>>>>>>>>>> The big problem with this is that it does not work with the deployment scanner.
>>>>>>>>>>>
>>>>>>>>>> Yeah, the deployment-scanner is always a story for itself. However i think we could actually make it persist information and be aware of overlays.
>>>>>>>>>>
>>>>>>>>>> Having overlays as part of the deployment means the lifecycle is managed together, so the deployment-scanner could define it's own invalidation policy. May it be based on whether the content got removed or we have a specific marker for that.
>>>>>>>>>>
>>>>>>>>>> We could also think of providing a file-based overlay solution, managed by the deployment scanner only. In the end people use the deployment-scanner for a reason, so perhaps not having to worry about the model or "content" folder could be interesting. This would not even need to access persistent information though. Anyway just some ideas on the side.
>>>>>>>>>>
>>>>>>>>>>> It also has to be specified on every re-deploy.
>>>>>>>>>> When you do a "remove" and "add" then yes. We do have specific operations to replace the content and redeploy the deployment without removing the information from the model.
>>>>>>>>>>
>>>>>>>>>>> I think the simplest solution here
>>>>>>>>>>> is to just move the links under the deployment-overlays element and loose the
>>>>>>>>>>> flexibility to link at different levels. e.g:
>>>>>>>>>>>
>>>>>>>>>>> /deployment-overlay=myOverlay/deployment=test.war
>>>>>>>>>>> /deployment-overlay=myOverlay/deployment=*.jar
>>>>>>>>>>>
>>>>>>>>>> Yes, i was not really going for the simplest solution for now - this would most likely would be it :)
>>>>>>>> _______________________________________________
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>>>>>>>> jboss-as7-dev at lists.jboss.org
>>>>>>>> https://lists.jboss.org/mailman/listinfo/jboss-as7-dev
>>>>>>>>
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>>>>>>
>>>>>
>>>>>
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