Affects Version/s: 0.5.0
Fix Version/s: 0.5.0
- 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.