Join an existing cluster instead of creating a new one

[cofyc]

Feature Request

Is your feature request related to a problem? Please describe:

Describe the feature you'd like:

This is an alternative way to migrate data from an existing cluster.

pros:

• smooth
• no extra data migration or binlog sync

cons:

• slow
• need support from tidb-operator (under investigation)

Describe alternatives you've considered:

Teachability, Documentation, Adoption, Migration Strategy:

[github-actions[bot]]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 15 days