[
https://issues.apache.org/jira/browse/HADOOP-10641?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14057265#comment-14057265
]
Aaron T. Myers commented on HADOOP-10641:
-----------------------------------------
Konst, you are overreacting here. As I said previously, I'm fine with you
proceeding with this on a development branch. That will give you an opportunity
to commit the coordination engine interface and start making progress on
HDFS-6469. If and when that materializes as a stable system that the community
wants to adopt into Hadoop, then we'll merge it back to trunk just like we've
done with many large features that are better accomplished via multiple JIRAs
and doing the work piecemeal. In particular, this comment doesn't make any
sense:
{quote}
Committing this to a development branch wouldn't make sense without you being
convinced or comfortable to have it merged to trunk once the work is done.
{quote}
The work on HDFS-6469 is not done, so how can I possibly know whether or not
I'll be convinced and comfortable to have it merged to trunk, when it is time
to merge the feature branch? My skepticism of this feature at this point is not
a good reason to commit it to trunk first without a development branch. I think
the exact opposite is the case: doing this on a feature branch is a way for you
to be able to demonstrate the benefits and prove out how low-risk the NN
changes are that are required for this work. I do not understand at all your
resistance to doing this work on a branch.
bq. Not sure which 3rd party system dependencies you see here. There are non
mentioned in the CNode design. And ZK is already a dependency for Hadoop HA.
Please give me a little more credit than this. Even though it may not be
mentioned in the design doc, it's fairly transparent that the primary goal of
this work is to introduce a plugin point for WANdisco's coordination engine
implementation into Hadoop.
I will try to make the meeting next week but at the moment my schedule does not
allow it. I will try to move things around, though. San Ramon is also a very
inconvenient location for me. Will there be a dial-in provided for those who
cannot attend in-person?
> Introduce Coordination Engine
> -----------------------------
>
> Key: HADOOP-10641
> URL: https://issues.apache.org/jira/browse/HADOOP-10641
> Project: Hadoop Common
> Issue Type: New Feature
> Affects Versions: 3.0.0
> Reporter: Konstantin Shvachko
> Assignee: Plamen Jeliazkov
> Attachments: HADOOP-10641.patch, HADOOP-10641.patch,
> HADOOP-10641.patch, hadoop-coordination.patch
>
>
> Coordination Engine (CE) is a system, which allows to agree on a sequence of
> events in a distributed system. In order to be reliable CE should be
> distributed by itself.
> Coordination Engine can be based on different algorithms (paxos, raft, 2PC,
> zab) and have different implementations, depending on use cases, reliability,
> availability, and performance requirements.
> CE should have a common API, so that it could serve as a pluggable component
> in different projects. The immediate beneficiaries are HDFS (HDFS-6469) and
> HBase (HBASE-10909).
> First implementation is proposed to be based on ZooKeeper.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
