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https://issues.apache.org/jira/browse/HADOOP-10641?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14068857#comment-14068857
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Andrew Purtell commented on HADOOP-10641:
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bq. I want a formal specification of the API, and what we have in the current
PDF design document is not it. I will also need evidence that the reference ZK
implementation is consistent with that specification, both by any maths that
can be provided, and the test cases derived from the specification.
This is a good idea in the abstract, but the notion of applying Amazon's
process to a volunteer open source project is problematic. In terms of the
Hadoop contribution process, this is a novel requirement. It is up to the
Hadoop committership to determine commit criteria of course, but I humbly
suggest that the intersection of contributors able to mathematically prove the
correctness of a large code change while simultaneously being able to implement
production quality systems code is vanishingly small. In this case, the
contributors might be able to meet the challenge but going forward if
significant changes to Hadoop will require a team of engineers and
mathematicians, probably this marks the end of external contributions to the
project. Also, I looked at HADOOP-9361. The documentation updates there are
fantastic but I did not find any mathematical proofs of correctness.
> 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.
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