[jira] [Commented] (HADOOP-7455) Introduce HA Service Protocol Interface

["Justin Joseph (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-7455?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13076208#comment-13076208 ] 

Justin Joseph commented on HADOOP-7455:
---------------------------------------

Will it be good idea to bring all the following life cycle management APIs under this interface?
{noformat}startInActive()
startInStandby()
stop()
{noformat} 

In our implementation (solution document attached in HDFS-2124) we handle network partitions (& split brain case) by introducing a new state for Namenode, termed as *_Neutral_*. In neutral mode, Namenode is neither Active nor Standby; it is just idle. Neutral state represents the situation where Namenode is alive, but is not able to contact the Zookeeper server (either because the Namenode is network partitioned or Zookeeper quorum is not satisfied). Handling network partitions in this manner is very effective for certain HA approaches, such as ZK based failover + Data Synchronization using Backup Node. Considering this, can we provide the following APIs also under this HA Service interface?
{noformat}activeToNeutral()
neutralToActive()
standByToNuetral()
neutralToStandBy(){noformat}

> Introduce HA Service Protocol Interface
> ---------------------------------------
>
>                 Key: HADOOP-7455
>                 URL: https://issues.apache.org/jira/browse/HADOOP-7455
>             Project: Hadoop Common
>          Issue Type: Sub-task
>          Components: util
>            Reporter: Suresh Srinivas
>            Assignee: Suresh Srinivas
>         Attachments: HADOOP-7455.1.patch, HADOOP-7455.2.patch, HADOOP-7455.3.patch, HADOOP-7455.4.patch, HDFS-7454.patch
>
>
> This jira introduces a protocol interface to be implemented by services that provide HA functionality.

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