[HBASE-6567] make memory locking configuration of regioservers more flexible

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.95.2
• Fix Version/s: 0.95.0
• Component/s: scripts
• Hadoop Flags: Incompatible change, Reviewed

Release Note

Removes --mlock start flag. Adds the below instead:

HBASE_REGIONSERVER_MLOCK binary: empty/not set – disabled, non empty – enabled
HBASE_REGIONSERVER_UID string: a target user for the running process regardless of any other feature that is enabled

• Assignee: Matteo Bertozzi
• Reporter: Roman Shaposhnik
• Created: 13/Aug/12 16:54
• Updated: 24/Apr/14 15:56
• Resolved: 18/Aug/12 21:48

Description

The current implementation of the memory locking feature of regisoservers has a downside of not being flexible to configure for permanent use. Sure there is a --mlock flag but that needs to be explicitly passed on every invocation and thus require extra steps to be configured for permanent use (IOW, there's not a single env variable I can set to have a desired effect). The only other alternative – the explicit setting of HBASE_REGIONSERVER_OPTS – has a downside of being pretty cryptic to the novice user and has a killer problem of not explicitly telling higher level scripts (like init.d or upstart ones) which user the initial hbase process should be executed as.

I propose a very simple solution (which is essentially making --mlock setting into an env. variable): add a variable called HBASE_REGIONSERVER_MLOCK that can be set in hbase-env.sh and has the following semantics:

• [default] not set: mlocking feature is disabled
• set but empty: mlocking feature is enabled and the target user is hbase
• set and not empty: mlocking feature is enabled and the target user is the value of the variable

Thoughts?

Issue Links

• supercedes: HBASE-4391 Add ability to start RS as root and call mlockall