[GitHub] [incubator-openwhisk] tysonnorris opened a new pull request #4326: Invoker backpressure

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tysonnorris opened a new pull request #4326: Invoker backpressure
URL: https://github.com/apache/incubator-openwhisk/pull/4326
 
 
   <!--- Provide a concise summary of your changes in the Title -->
   Invoker use of cluster managed resources should allow dynamic cluster resizing.
   
   ## Description
   <!--- Provide a detailed description of your changes. -->
   <!--- Include details of what problem you are solving and how your changes are tested. -->
   Currently, invoker has a static config `whisk.container-pool.user-memory` that affects:
   * controller sharding across invokers
   * invoker's concept of ability to launch containers
   
   This does not work well in an environment that may scale up in hosts to accommodate the ability to launch more containers. Making that config "dynamic" is also not the best solution since the invoker really has no say in ability to launch a container (in this case of cluster managed action containers, at least), and therefore relying on it at either controller or invoker layer is problematic.
   
   This PR introduces:
   * config flag to enable cluster managed resources - this is separate from ContainerFactory, and introduces some addition logic to ContainerPool
   * NodeStats - collected at ContainerPool from akka system event stream, and used to determine (which respect to latest snapshot of data) whether a container is launchable
   * Reservations - tracked at ContainerPool to accommodate timing delays between cluster manager container starts/stops, and updates to NodeStats
   
   See proposal on apache wiki here: 
   https://cwiki.apache.org/confluence/display/OPENWHISK/Cluster+Manager+Resources+in+Invoker  
   
   
   
   ## Related issue and scope
   <!--- Please include a link to a related issue if there is one. -->
   - [ ] I opened an issue to propose and discuss this change (#????)
   
   ## My changes affect the following components
   <!--- Select below all system components are affected by your change. -->
   <!--- Enter an `x` in all applicable boxes. -->
   - [ ] API
   - [ ] Controller
   - [ ] Message Bus (e.g., Kafka)
   - [ ] Loadbalancer
   - [x] Invoker
   - [ ] Intrinsic actions (e.g., sequences, conductors)
   - [ ] Data stores (e.g., CouchDB)
   - [ ] Tests
   - [ ] Deployment
   - [ ] CLI
   - [ ] General tooling
   - [ ] Documentation
   
   ## Types of changes
   <!--- What types of changes does your code introduce? Use `x` in all the boxes that apply: -->
   - [ ] Bug fix (generally a non-breaking change which closes an issue).
   - [x] Enhancement or new feature (adds new functionality).
   - [ ] Breaking change (a bug fix or enhancement which changes existing behavior).
   
   ## Checklist:
   <!--- Please review the points below which help you make sure you've covered all aspects of the change you're making. -->
   
   - [x] I signed an [Apache CLA](https://github.com/apache/incubator-openwhisk/blob/master/CONTRIBUTING.md).
   - [x] I reviewed the [style guides](https://github.com/apache/incubator-openwhisk/wiki/Contributing:-Git-guidelines#code-readiness) and followed the recommendations (Travis CI will check :).
   - [ ] I added tests to cover my changes.
   - [ ] My changes require further changes to the documentation.
   - [ ] I updated the documentation where necessary.
   
   

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