[HBASE-21073] "Maintenance mode" master

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0-alpha-1, 2.2.0, 2.1.1, 2.0.3
• Component/s: amv2, hbck2, master

Release Note

    Instead of being an ephemeral state set by hbck, maintenance mode is now
    an explicit toggle set by either configuration property or environment
    variable. In maintenance mode, master will host system tables and not
    assign any user-space tables to RSs. This gives operators the ability to
    affect repairs to meta table with fewer moving parts.

• Assignee: Mike Drob
• Reporter: Michael Stack
• Created: 19/Aug/18 11:00
• Updated: 25/Jul/19 22:24
• Resolved: 23/Oct/18 15:00

Description

Make it so we can bring up a Master in "maintenance mode". This is parse of master wal procs but not taking on regionservers. It would be in a state where "repair" Procedures could run; e.g. a Procedure that could recover meta by looking for meta WALs, splitting them, dropping recovered.edits, and even making it so meta is readable. See parent issue for why needed (disaster recovery).

Issue Links

• links to: Review Board (master)