chore: add local development with SDK backends guide

[Raakshass]

Closes #259

Summary

This PR adds a Local Development with SDK Backends guide to help users understand and switch between available training backends.

Content Covered

• Backend comparison table (LocalProcess, Container, Kubernetes)
• When to use each backend - quick prototyping vs distributed training vs production
• Code examples for each backend configuration
• Switching between backends - same trainer code works across all backends
• Common operations (list jobs, view logs, wait, delete)
• Troubleshooting tips for each backend

Changes Based on Feedback

Revised from contributor dev setup to user-facing backends guide per @Fiona-Waters feedback.

Checklist

• Follows existing documentation style (RST format)
• Aligned with kubeflow.org Trainer docs structure
• Includes comparison table as requested in Document Local Development #259

[google-oss-prow]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by:
Once this PR has been reviewed and has the lgtm label, please assign andreyvelich for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Details

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[github-actions]

🎉 Welcome to the Kubeflow SDK! 🎉

Thanks for opening your first PR! We're happy to have you as part of our community 🚀

Here's what happens next:

• If you haven't already, please check out our Contributing Guide for repo-specific guidelines and the Kubeflow Contributor Guide for general community standards
• Our team will review your PR soon! cc @kubeflow/kubeflow-sdk-team

Join the community:

• Slack: Join our #kubeflow-ml-experience and #kubeflow-trainer Slack channels
• Meetings: Attend the Kubeflow SDK and ML Experience bi-weekly meetings

Feel free to ask questions in the comments if you need any help or clarification!
Thanks again for contributing to Kubeflow! 🙏

[Fiona-Waters]

@Raakshass Thank you for your interest in contributing. The aim of this issue is to add a guide for customers that would like to use our local and container backends. We would like to show them how to easily switch between available backends, when to use each of them etc. Please re-read the issue description and let me know if you have any questions.

[Raakshass]

Thanks @Fiona-Waters for the clarification! I misunderstood the scope - I'll revise my PR to focus on the user-facing local and container backends guide instead of contributor dev setup.

I'll update it to cover:

• Backend comparison (LocalProcess vs Container vs Kubernetes)
• When to use each backend
• Code examples for switching between backends
• Common operations and troubleshooting

Will push the updated content shortly!

[Raakshass]

@Fiona-Waters I updated the PR content described above. I'm unable to edit the PR title to "docs: add local development with SDK backends guide" - could you please update it? Thanks!

[Raakshass]

@Fiona-Waters I've updated the PR content as you suggested - it now covers the user-facing backends guide with comparison table, switching examples, and troubleshooting tips. Ready for re-review when you have time!

[Fiona-Waters]

Thanks @Raakshass I think this is great. Could we add something around differing container_host for use on mac for example? This could be tricky if the user doesn't know about it.

[Fiona-Waters]

Thanks @Raakshass
You also need to add to https://github.com/kubeflow/sdk/blob/main/docs/source/index.rst?plain=1 so that the new section will show on the website.

[Raakshass]

@Fiona-Waters — addressed both asks:

Container host info for Mac — added Container Host Configuration section with OS-specific socket paths table and macOS code example
Updated grid-item-card + main index.rst — better description + added to toctree
Ready for re-review. Thanks!

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

[coveralls]

Pull Request Test Coverage Report for Build 22003433482

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 72.824%

---

Totals
Change from base Build 21955571005:	0.0%
Covered Lines:	4092
Relevant Lines:	5619

---

💛 - Coveralls

[Raakshass]

@Fiona-Waters Rebased onto latest main to fix the coveralls base-commit drift. Both your review items are addressed:

1. Container host config for macOS — added Container Host Configuration section with OS-specific socket paths table and macOS code example
2. Updated index.rst — added to toctree and grid-item-card in getting-started page

All CI checks passing. Ready for re-review when you get a chance. Thanks!