Query on on-prem habitat to github/bitbucket

Does on-prem habitat builder will support only OAUTH functionality to authenticate to github ? or any other functionality can also support ?

Yes. To be precise, on-prem habitat builder supports only OAUTH2 from these vendors:

  • Chef Automate v2
  • Azure AD
  • GitHub
  • GitHub Enterprise
  • GitLab
  • Okta
  • Bitbucket (cloud)
  • additional providers may be added on request

ref: https://github.com/habitat-sh/on-prem-builder#requirements