LFX: Enhance flag support across Vitess components (Tracking Issue)

[rohit-nayak-ps]

Notes for Potential LFX Mentees:

This project is part of the LFX program. More information at https://github.com/cncf/mentoring/tree/main/lfx-mentorship. For mentees, details on how to apply are at https://github.com/cncf/mentoring/tree/main/lfx-mentorship#how-to-apply.
For those thinking of applying, the contribution guide has information on learning both golang and Vitess concepts for someone new to Vitess.

⚠️ If you're thinking about opening PRs to the project before the application period begins, please read the initial sections regarding contribution guidelines and advice from a previous gsoc project!

Also, please do not DM the mentors or other Vitess maintainers on this issue, Slack or elsewhere in this regard: your LFX application should speak for itself. 🙏🏽

Feature Description

As part of a major Vitess Flag Restructure Vitess v17 introduced viper, a library to provide unified configuration management, to the project.

This also supports dynamic flag configuration . While some parts of Vitess has been modified to take advantage of this feature, there are several components that are either yet to adopt it or have only partially adopted it.

In addition we have been deprecating flags with underscores in preference to ones with dashes. We will be completely removing the deprecated flags in v24 and hence need to make the required changes asap.

This is an umbrella issue for adding dynamic flag support and the flag renaming.

Previous PRs related to this:

• [RFC] Standardized viper framework for vitess configuration parameters #11456
• Improve VTOrc config handling to support dynamic variables #17218
• Allow for dynamic configuration of DDL settings #17328
• Make transaction mode a dynamic configuration #17419
• Change keys of the discovery flags such that they conform to the convention #17430

Action items

This is an initial set which will be updated before the project starts.

Dynamic Flags

• Feature Request: Support dynamically adjusting the number of transaction connection pools and read-only connection pools #17046
• Make required changes for vttablet
  • Re-work and complete begin viperizing tabletserver - max/warn result size, cache memory #14548
  • Replace existing yaml config support with standard viper implementation
  • Identify remaining config that can be made dynamic and implement
• Make required changes for vtgate
• Make required changes for vtctld
• Review and update Documentation on vitess.io
• Review and update Examples

Flag Renaming

• Review codebase and make required changes. It is highly recommended to use scripting to make all the edits at once versus doing them by hand.
• Review and update Documentation on vitess.io
• Review and update Examples