sedna/docs/proposals/lifelong-learning/structured-lifelong-learning.md

• Lifelong Learning
• • Goals
  • Proposal
  • • Use Cases
  • Design Details
  • • CRD API Group and Version
    • Lifelong learning CRD
    • Lifelong learning job type definition
    • • Validation
    • Lifelong learning job sample
  • Controller Design
  • • Lifelong Learning Controller
    • Downstream Controller
    • Upstream Controller
    • Details of api between GM(cloud) and LC(edge)
    • The flows of lifelong learning job
  • Workers Communication

• Lifelong Learning
  • Goals
  • Proposal
    • Use Cases
  • Design Details
    • CRD API Group and Version
    • Lifelong learning CRD
    • Lifelong learning type definition
    • Lifelong learning sample
    • Validation
  • Controller Design
    • Lifelong Learning Controller
    • Downstream Controller
    • Upstream Controller
    • Details of api between GM(cloud) and LC(edge)
  • Workers Communication

Lifelong Learning

Goals

In this version of Sedna lifelong learning framework, we realize the following features:

• edge-cloud collaborative continuous learning.
• Knowledge sharing across the edge of the cloud.
• Automatic discovery and transfer learning of new knowledge.

Proposal

We propose using Kubernetes Custom Resource Definitions (CRDs) to describe
the lifelong learning specification/status and a controller to synchronize these updates between edge and cloud.

Use Cases

• Users can create the lifelong learning jobs, by providing training scripts, configuring training hyperparameters, providing training datasets, configuring training and deployment triggers.

Design Details

There are three stages in a lifelong learning job: train/eval/deploy.

Each stage contains these below states:

1. Waiting: wait to trigger satisfied, i.e. wait to train/eval/deploy
2. Ready: the corresponding trigger satisfied, now ready to train/eval/deploy
3. Starting: the corresponding stage is starting
4. Running: the corresponding stage is running
5. Failed: the corresponding stage failed
6. Completed: the corresponding stage completed

CRD API Group and Version

The LifelongLearningJob CRD will be namespace-scoped.
The tables below summarize the group, kind and API version details for the CRD.

• LifelongLearningJob

Field	Description
Group	sedna.io
APIVersion	v1alpha1
Kind	LifelongLearningJob

Lifelong learning CRD

See the crd source for details.

Lifelong learning job type definition

See the golang source for details.

Validation

Open API v3 Schema based validation can be used to guard against bad requests.
Invalid values for fields (example string value for a boolean field etc) can be validated using this.

Here is a list of validations we need to support :

1. The dataset specified in the crd should exist in k8s.
2. The edgenode name specified in the crd should exist in k8s.

Lifelong learning job sample

See the source for an example.

Controller Design

The Lifelong learning controller starts three separate goroutines called upstream, downstream and Lifelonglearningjobcontroller.

These are not separate controllers as such but named here for clarity.

• Lifelong learning: watch the updates of lifelong-learning job crds, and create the workers depending on the state machine.
• downstream: synchronize the lifelong-learning-job updates from the cloud to the edge node.
• upstream: synchronize the lifelong-learning-job updates from the edge to the cloud node.

Lifelong Learning Controller

The lifelong-learning controller watches for the updates of lifelong-learning jobs and the corresponding pods against the K8S API server.

Updates are categorized below along with the possible actions:

Update Type	Action
New lifelong-learning-job Created	Wait to train trigger satisfied
lifelong-learning-job Deleted	NA. These workers will be deleted by k8s gc.
The Status of lifelong-learning-job Updated	Create the train/eval worker if it's ready.
The corresponding pod created/running/completed/failed	Update the status of lifelong-learning job.

Downstream Controller

The downstream controller watches for the lifelong-learning job updates against the K8S API server.

Updates are categorized below along with the possible actions that the downstream controller can take:

Update Type	Action
New Lifelong-learning-job Created	Sends the job information to LCs.
Lifelong-learning-job Deleted	The controller sends the delete event to LCs.

Upstream Controller

The upstream controller watches for the lifelong-learning job updates from the edge node and applies these updates against the API server in the cloud.

Updates are categorized below along with the possible actions that the upstream controller can take:

Update Type	Action
Lifelong-learning-job Reported State Updated	The controller appends the reported status of the job by LC in the cloud.

Details of api between GM(cloud) and LC(edge)

Reference

The flows of lifelong learning job

• Flow of the job creation:

• Flow of the train stage:

• Flow of the eval stage:

• Flow of the deploy stage:

Workers Communication

No need to communicate between workers.