[ACCUMULO-1049] Master does not need to get tserver lock

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.4.0
• Fix Version/s: 1.4.3, 1.5.0
• Component/s: master
• Assignee: Keith Turner
• Reporter: Keith Turner
• Created: 07/Feb/13 21:14
• Updated: 02/Mar/13 09:48
• Resolved: 01/Mar/13 20:19

Description

Every tserver has a lock in zookeeper. The master tries to get this lock and when it does it assumes the tserver is dead. It seems like this may no longer be necessary since changes made in 1.3. The master used to only keep track of ip and port to identify a tablet server. It needed to know when it got the lock to detect the difference between two tablet server instances at the same ip and port.

Since 1.3 the master keeps distinctive info about a tablet server now and can detect the difference between tablet server instances. Making the master just monitor the current tablet server locks instead of trying to get the lock would simplify the master code.

Issue Links

• supercedes: ACCUMULO-799 ZooLock should not set a watch in its constructor
• supercedes: ACCUMULO-1050 Master assumes tserver lost lock when it fails to get lock

Sub-Tasks

• MAster is not seeing tablet server go away: Resolved