chore(doc): Update README.md (#1387)

1. Fix Slack expiration link
2. Update minimum version of kubectl
3. Add training operator installation details

README.md

@@ -1,56 +1,76 @@
-# K8s Custom Resource and Operator For TensorFlow jobs
+# Kubeflow Training Operator
 
 [![Build Status](https://travis-ci.org/kubeflow/tf-operator.svg?branch=master)](https://travis-ci.org/kubeflow/tf-operator)
 [![Coverage Status](https://coveralls.io/repos/github/kubeflow/tf-operator/badge.svg?branch=master)](https://coveralls.io/github/kubeflow/tf-operator?branch=master)
 [![Go Report Card](https://goreportcard.com/badge/github.com/kubeflow/tf-operator)](https://goreportcard.com/report/github.com/kubeflow/tf-operator)
 
 ## Overview
 
-TFJob provides a Kubernetes custom resource that makes it easy to
-run distributed or non-distributed TensorFlow jobs on Kubernetes.
-
-- For a complete reference of the custom resource definitions, please refer to the [API Definition](pkg/apis/tensorflow/v1/types.go).
-- For details on its design, please refer to the [v1alpha2 design doc](https://github.com/kubeflow/community/blob/master/proposals/tf-operator-design-v1alpha2.md).
+Before v1.2 release, tensorflow-operator can only support TFJob on Kubernetes.
+Starting from v1.3, Training Operator provides Kubernetes custom resources that makes it easy to
+run distributed or non-distributed TensorFlow/PyTorch/MXNet/XGBoost jobs on Kubernetes.
+
+- For a complete reference of the custom resource definitions, please refer to the API Definition.
+  - [Tensorflow API Definition](pkg/apis/tensorflow/v1/types.go)
+  - [PyTorch API Definition](pkg/apis/pytorch/v1/types.go)
+  - [MXNet API Definition](pkg/apis/mxnet/v1/types.go)
+  - [XGBoost API Definition](pkg/apis/xgboost/v1/types.go)
+- For details on API design, please refer to the [v1alpha2 design doc](https://github.com/kubeflow/community/blob/master/proposals/tf-operator-design-v1alpha2.md).
+- For details of all-in-one operator design, please refer to the [All-in-one Kubeflow Training Operator](https://docs.google.com/document/d/1x1JPDQfDMIbnoQRftDH1IzGU0qvHGSU4W6Jl4rJLPhI/edit#heading=h.e33ufidnl8z6)
 - For details on its obersibility, please refer to the [monitoring design doc](docs/monitoring/README.md).
 
 ## Prerequisites
 
 * Version >= 1.16 of Kubernetes
+* Version >= 3.x of Kustomize
+* Version >= 1.21.x of Kubectl
 
 ## Installation
 
 ### Master Branch
 
 ```bash
-kubectl kustomize "github.com/kubeflow/tf-operator.git/manifests/overlays/standalone?ref=master" | kubectl apply -f -
+kubectl apply -k "github.com/kubeflow/tf-operator.git/manifests/overlays/standalone?ref=master"
 ```
 
 ### Specific Release
 
 ```bash
-kubectl kustomize "github.com/kubeflow/tf-operator.git/manifests/overlays/standalone?ref=v1.1.0" | kubectl apply -f -
+kubectl apply -k "github.com/kubeflow/tf-operator.git/manifests/overlays/standalone?ref=v1.3.0"
+```
+
+### Tensorflow Release Only
+
+For users who prefer to use original tensorflow controllers, please checkout v1.2-branch, we will maintain the bug fix in this branch.
+
+```bash
+kubectl apply -k "github.com/kubeflow/tf-operator.git/manifests/overlays/standalone?ref=v1.2.0"
 ```
 
 ## Quick Start
 
-Please refer to the [quick-start-v1.md](docs/quick-start-v1.md) and [Kubeflow user guide](https://www.kubeflow.org/docs/guides/components/tftraining/) for more information.
+Please refer to the [quick-start-v1.md](docs/quick-start-v1.md) and [Kubeflow Training User Guide](https://www.kubeflow.org/docs/guides/components/tftraining/) for more information.
 
 ## API Documentation
 
-Please refer to [API Documentation](docs/api/generated.asciidoc)
+Please refer to API Documentation.
+- [Tensorflow API Documentation](docs/api/tensorflow_generated.asciidoc)
+- [PyTorch API Documentation](docs/api/pytorch_generated.asciidoc)
+- [MXNet API Documentation](docs/api/mxnet_generated.asciidoc)
+- [XGBoost API Documentation](docs/api/xgboost_generated.asciidoc)
 
 ## Community
 
 You can:
 
-- Join our [Slack](https://join.slack.com/t/kubeflow/shared_invite/zt-lhkwrmkh-JPT2g9eva1oPkS00~VHZDQ) channel.
+- Join our [Slack](https://join.slack.com/t/kubeflow/shared_invite/zt-n73pfj05-l206djXlXk5qdQKs4o1Zkg) channel.
 - Check out [who is using this operator](./docs/adopters.md).
 
 This is a part of Kubeflow, so please see [readme in kubeflow/kubeflow](https://github.com/kubeflow/kubeflow#get-involved) to get in touch with the community.
 
 ## Contributing
 
-Please refer to the [developer_guide](docs/development/developer_guide.md)
+Please refer to the [DEVELOPMENT](docs/development/developer_guide.md)
 
 
 ## Change Log
@@ -63,5 +83,8 @@ The following table lists the most recent few versions of the operator.
 
 | Operator Version | API Version | Kubernetes Version |
 | ------------- | ------------- | ------------- |
-| `latest` (master HEAD) | `v1` | 1.16+ |
 | `v1.0.x`| `v1` | 1.16+ |
+| `v1.1.x`| `v1` | 1.16+ |
+| `v1.2.x`| `v1` | 1.16+ |
+| `v1.3.x`| `v1` | 1.18+ |
+| `latest` (master HEAD) | `v1` | 1.18+ |