gianny DAMOUR wrote:
[Sorry for this delay.]
Greg Wilkins wrote:
The HTTP protocol extensions, which are pretty straight forward extensions to the HTTP RFC, something that can be implemented simply in a servlet. This should be able to be written (or borrowed) without being dependant on any particular HTTP server.
I agree.
A configuration control mechanism that allows content to be reliably updated on the server and version controlled. I think that this should probably be a very Geronimo specific service. We have to work out what it means to use WEBDAV to put content on a geroninmo node - does that mean that we are deploying to that node or that we are deploying to that geronimo cluster? Will we delay any WEBDAV acks to the client until we know the content has been replicated?
I think that deployments should be transactional. For instance, when deploying an EAR to a given cluster, this enterprise archive should be running on each node of the cluster. If the deployment is not possible on a given node, then it seems to be safe to also fail the deployment on the other nodes.
homogeneous
It means that the distribution phase should also be transactional at the cluster level. Furthermore, if one wants to allow pinned-deployments, deployment on a specific node of a cluster, then it means that one should be able to distribute only to a given set of nodes.
heterogeneous
In a heterogeneous situation, I would like to see the cluster itself being responsible for where nodes, or even whole tiers (given that services are just another type of deployable) are actually running.
I guess we should be able to give hints as to where an app might be deployed...
Imagine a cluster with decent monitoring and introspective abilities, a rules engine and the knowledge to tune and reorganise itself on the fly. It might choose to move a very heavily loaded app onto one side and partition it separately from a host of smaller less demanding applications etc... The possibilities are limitless.
Based on these ideas, I think that when distributing a component, one should allow the end-user to choose the target nodes and also provide some convenience methods to choose all the nodes of a cluster.
I think we need a number of pluggable policies - the most simple being e.g. homogeneous/all and heterogeneous/manual, then the really crazy people can start thinking about heterogeneous/automatic :-)
Jules
So the architecture that I had in my mind for WEBDAV, was a geronimo service that provided a distributed transactional file system type semantics. We would then adapt an existing WEBDAV servlet to talk to this service.
I think that I understand what you had in mind.
I will attempt a second try.
Thanks for the inputs, Gianny
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