Update release document

Signed-off-by: Andrey Velichkevich <[email protected]>

docs/release/README.md

@@ -2,25 +2,104 @@
 
 ## Prerequisite
 
-1. Permissions
-   - You need write permissions on the repository to create a release tag/branch.
-1. Prepare your Github Token
+- [Write](https://docs.github.com/en/organizations/managing-access-to-your-organizations-repositories/repository-permission-levels-for-an-organization#permission-levels-for-repositories-owned-by-an-organization)
+  permission for the Training Operator repository.
+
+- Maintainer access to the [Training SDK](https://pypi.org/project/kubeflow-training/).
+
+- Create a [GitHub Token](https://docs.github.com/en/github/authenticating-to-github/keeping-your-account-and-data-secure/creating-a-personal-access-token).
+
+- Install `PyGithub` to generate the [Changelog](./../../CHANGELOG.md):
+
+  ```
+  pip install PyGithub==1.55
+  ```
+
+- Install `twine` to publish the SDK package:
+
+  ```
+  pip install twine==3.4.1
+  ```
+
+  - Create a [PyPI Token](https://pypi.org/help/#apitoken) to publish Training SDK.
+
+  - Add the following config to your `~/.pypirc` file:
+
+    ```
+    [pypi]
+       username = __token__
+       password = <PYPI_TOKEN>
+    ```
+
+## Versioning policy
+
+Training Operator version format follows [Semantic Versioning](https://semver.org/).
+Training Operator versions are in the format of `vX.Y.Z`, where `X` is the major version, `Y` is
+the minor version, and `Z` is the patch version.
+The patch version contains only bug fixes.
+
+Additionally, Training Operator does pre-releases in this format: `vX.Y.Z-rc.N` where `N` is a number
+of the `Nth` release candidate (RC) before an upcoming public release named `vX.Y.Z`.
+
+## Release branches and tags
+
+Training Operator releases are tagged with tags like `vX.Y.Z`, for example `v0.11.0`.
+
+Release branches are in the format of `vX.Y-branch`, where `X.Y` stands for
+the minor release.
+
+`vX.Y.Z` releases are released from the `vX.Y-branch` branch. For example,
+`v1.8.0` release should be on `v1.8-branch` branch.
+
+If you want to push changes to the `vX.Y-branch` release branch, you have to
+cherry pick your changes from the `master` branch and submit a PR.
+
+## Create a new Training Operator release
+
+### Create release branch
+
+1. Depends on what version you want to release,
+
+   - Major or Minor version - Use the GitHub UI to create a release branch from `master` and name
+     the release branch `vX.Y-branch`
+   - Patch version - You don't need to create a new release branch.
+
+1. Fetch the upstream changes into your local directory:
 
-1. Install Github python dependencies to generate changlog
    ```
-   pip install PyGithub==1.55
+   git fetch upstream
    ```
 
-### Release Process
+1. Checkout into the release branch:
 
-1. Make sure the last commit you want to release past `kubeflow-training-operator-postsubmit` testing.
+   ```
+   git checkout vX.Y-branch
+   ```
 
-1. Check out that commit (in this example, we'll use `6214e560`).
+### Release Training SDK
 
-1. Depends on what version you want to release,
+1. Update the [VERSION in `gen-sdk.sh` script](../../hack/python-sdk/gen-sdk.sh#L27) with this
+   semantic: `X.Y.ZRC.N` for the RC or `X.Y.Z` for the public release.
+
+   For example:
+
+   ```
+   VERSION=1.8.0rc1
+   ```
+
+1. Generate Training SDK:
+
+   ```
+   make generate
+   ```
 
-   - Major or Minor version - Use the GitHub UI to cut a release branch and name the release branch `v{MAJOR}.${MINOR}-branch`
-   - Patch version - You don't need to cut release branch.
+1. Submit PR
+
+#### Release Training Operator Image
+
+1. Make sure the last commit you want to release past `kubeflow-training-operator-postsubmit` testing.
+
+1. Check out that commit (in this example, we'll use `6214e560`).
 
 1. Create a new PR against the release branch to change container image in manifest to point to that commit hash.