Details
-
Bug
-
Status: Open
-
Major
-
Resolution: Unresolved
-
0.24.0
-
None
-
None
Description
As discussed in HADOOP-8206, the current design for automatic failover has the following race:
- ZKFC1 gets active lock
- ZKFC1 is about to send transitionToActive() and machine freezes (eg GC pause + swapping)
- ZKFC1 loses its ZK lock, ZKFC2 gets ZK lock
- ZKFC2 calls transitionToStandby on NN1, and transitions NN2 to active
- ZKFC1 wakes up from pause, calls transitionToActive(), now we have a bad situation
This is rare, since it requires ZKFC1 to freeze longer than its ZK session timeout, but worth fixing, since the results can be disastrous.
Attachments
Attachments
Issue Links
- is related to
-
HADOOP-13515 Redundant transitionToActive call can cause a NameNode to crash
- Open
- relates to
-
HADOOP-8206 Common portion of ZK-based failover controller
- Closed
-
HDFS-3042 Automatic failover support for NN HA
- Closed