[
https://issues.apache.org/jira/browse/S4-24?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13152111#comment-13152111
]
Matthieu Morel commented on S4-24:
----------------------------------
Yes, that's a possible case, that's why we'll have to synchronize among
multiple nodes.
The idea would be that:
1. when a new app is available, all nodes must first load this app
2. then when all nodes have loaded the app, (and that it has been verified in
some way) , init and start routines can proceed. If all nodes cannot load the
app after a given timeout, we should rollback and unload the app.
3. during runtime, if a node fails, the failover procedure should bring a warm
node to the cluster, without the need to re-fetch the application. This implies
that standby nodes must also load the apps. And that the synchronization among
nodes and apps should also include those standby nodes, somehow.
> Dynamic deployment of S4 applications from a remote repository
> --------------------------------------------------------------
>
> Key: S4-24
> URL: https://issues.apache.org/jira/browse/S4-24
> Project: Apache S4
> Issue Type: Sub-task
> Affects Versions: 0.5
> Reporter: Matthieu Morel
> Assignee: Matthieu Morel
> Fix For: 0.5
>
>
> Use case:
> - at startup or during runtime, s4 nodes are notified of new applications
> available. The code for these applications is fetched from a remote
> repository, installed on S4 nodes, and the applications are started
> automatically.
> How does it work?
> - Zookeeper is used for coordination: when a new app is available, it creates
> a new znode under /s4-cluster-name/apps/app1
> - S4 nodes are notified of this new znode, which contains the s4r URI as
> metadata
> - S4 nodes can then fetch the s4r, copy it to a local directory and start it
> - we also need a facility to create the app into Zookeeper, along with
> required metadata
> For a first milestone, I suggest:
> - a simple file system based repository (can be a distributed file system)
> - deployment only, no unloading
> Later we can add extensions:
> - We could provide various repository clients, depending on the protocol
> specified, and on the level of trust of the repository (although for a first
> version, we would just provide a simple mechanism and assume a trustworthy
> environment).
> - more metada in the application znode, in order to control the state of the
> app, a time to start / stop, a number of nodes, nodes requirements etc...
> I'll start working on a first implementation, and I'm eager to receive
> suggestions.
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators:
https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira
