Bulk Operation

HADOOP-7454 HA: RetriableCommand is using RetryPolicy incorrectly after HADOOP-7896

HADOOP-7454 HA: void methods can swallow exceptions when going through failover path

HADOOP-7454 HA: log a warning when a failover is first attempted

HADOOP-7454 HA: Add 'ipc.client.connect.max.retries.on.timeouts' entry in core-default.xml file.

HADOOP-7454 Add ZK client for leader election

HADOOP-7454 HA: the FailoverController should check the standby is ready before failing over

HADOOP-7454 HA: failover should be able to pass args to fencers

HADOOP-7454 HA: HAServiceProtocol exceptions need to be unwrapped before it can be used

HADOOP-7454 All HAServiceProtocol methods have to throw IOException since they are invoked over the network

HADOOP-7454 HA: fencing mechanism

HADOOP-7454 HA: failover should error out if either host is not specified in the configs

HADOOP-7454 HA: the FailoverController should optionally fence the active during failover

HADOOP-7454 HA : Make client connection retries on socket time outs configurable.

HADOOP-7454 HA: Client failover policy is incorrectly trying to fail over all IOExceptions

HADOOP-7454 Add interface and update CLI to query current state to HAServiceProtocol

HADOOP-7454 
FailoverController for client-based configuration

HADOOP-7454 HA: Improve some logging for client IPC failovers and StandbyExceptions

HADOOP-7454 StandbyException should extend IOException

HADOOP-7454 HA: if both NNs are in Standby mode, client needs to try failing back and forth several times with sleeps

HADOOP-7454 HA: Administrative CLI to control HA daemons

HADOOP-7454 Introduce HA Service Protocol Interface

HADOOP-7454 Add client failover functionality to o.a.h.io.(ipc|retry)