Ayush Saxena commented on HDFS-14998:

[~ferhui] you need to exactly copy paste the words, if you have understood what 
[~csun] meant to say, you can write in your words, what you feel shall convey 
the meaning to all.
Let me clear it once more, Earlier ZKFC was not allowed to run, on the node 
running Observer Namenode, since ZKFC wasn't aware what about ONN, it used to 
transition it to Standby, so it was mandatory to turn the ZKFC off on Observer 
Namenode, if you want to use the feature.
In the present scenario, ZKFC is aware about Observer Namenode, it doesn't 
bother the Observer Namenode, so you can have ZKFC running on the Observer 
Node, it is now not compulsory to turn it off. But it is not required for a 
person to turn it on for normal working of Observer since Observer can not 
participate in failover, But if a user has a usecase where he keeps on changing 
the state of Observer to Standby back and forth depending on load or some 
condition (Either manually or through scripts), he can keep the ZKFC running so 
as when the Namenode is moved to Standby State it can participate in Automatic 
Failover, With ZKFC being aware of the ONN, this will shed the need of turning 
on and off the ZKFC when the namenode transitions states.

We are just being suggestive, not forcing any user to choose any way, whatever 
his use case may be he can go ahead, What Chao mentioned is one use case where 
ZKFC can be kept running on ONN. If someone doesn't have such a use case, he is 
free to turn the ZKFC off.

You can frame it in your own words, Whatever way you think you can convey the 
user correctly in less words, shall be fine for both of us.
[~csun] correct me, if I have gone wrong in the concept somewhere.

> Update Observer Namenode doc for ZKFC after HDFS-14130
> ------------------------------------------------------
>                 Key: HDFS-14998
>                 URL: https://issues.apache.org/jira/browse/HDFS-14998
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: documentation
>    Affects Versions: 3.3.0
>            Reporter: Fei Hui
>            Assignee: Fei Hui
>            Priority: Minor
>         Attachments: HDFS-14998.001.patch, HDFS-14998.002.patch, 
> HDFS-14998.003.patch
> After HDFS-14130, we should update observer namenode doc, observer namenode 
> can run with ZKFC running

This message was sent by Atlassian Jira

To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org

Reply via email to