[HDDS-4569] Add pre append gate and marker file to OM prepare state

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Component/s: OM, Ozone Manager
• Labels: pull-request-available
• Target Version/s: 1.2.0
• Assignee: Ethan Rose
• Reporter: Ethan Rose
• Created: 09/Dec/20 18:12
• Updated: 25/Jan/21 17:14
• Resolved: 04/Jan/21 19:23

Description

Add a gate to the pre append step of OzoneManagerStateMachine to block further write requests from coming in when an ozone manager is prepared. Also add a marker file that is written when the OM is prepared so that if it is restarted without a special flag, it automatically enters prepare mode.

Issue Links

• requires: RATIS-1216 State machine preAppend callback can throw exception without having leader to step down.
• links to: GitHub Pull Request #1705