SKIPCI: Datastore api

[yyongycy]

What changes are proposed in this pull request?

Please outline the changes and how this PR fixes the issue.

Why are the changes needed?

Please clarify why the changes are needed. For instance,

1. If you propose a new API, clarify the use case for a new API.
2. If you fix a bug, describe the bug.

Does this PR introduce any user facing changes?

Please list the user-facing changes introduced by your change, including

1. change in user-facing APIs
2. addition or removal of property keys
3. webui

[alluxio-bot]

Automated checks report:

• PR title follows the conventions: FAIL
  • The title of the PR does not pass all the checks. Please fix the following issues:
    • First word of title ("SKIPCI:") is not an imperative verb. Please use one of the valid words
• Commits associated with Github account: PASS

Some checks failed. Please fix the reported issues and reply 'alluxio-bot, check this please' to re-run checks.