Hello Folks,
I just filed a Umbrella jira today to address current NetworkTopology
issue that binding strictly to three tier network. The motivation here is to
make hadoop more flexible for deploying topology (especially for
cloud/virtualization case) and more configurable in data locality related
policies like: replica placement, task scheduling, choosing block for DFSClient
reading, balancing.
We submit a draft proposal in this Umbrella as well as the implementation
code. As code base is large (~260K), the code is separated into 7 sub JIRA
issues which seems to be more convenient for reviewing. However, we split the
code based on functionality which cause some dependencies between patches which
way we are not sure the best. Welcome to provide comments and suggestions on
doc and code, and look forward to work with all of you to enhance hadoop in
some new situations towards perfect.
Hope this is a good start.
Cheers,
Junping
----- Original Message -----
From: "Junping Du (JIRA)" <j...@apache.org>
To: common-iss...@hadoop.apache.org
Sent: Monday, June 4, 2012 12:09:22 PM
Subject: [jira] [Created] (HADOOP-8468) Umbrella of enhancements to support
different failure and locality topologies
Junping Du created HADOOP-8468:
----------------------------------
Summary: Umbrella of enhancements to support different failure and
locality topologies
Key: HADOOP-8468
URL: https://issues.apache.org/jira/browse/HADOOP-8468
Project: Hadoop Common
Issue Type: Bug
Components: ha, io
Affects Versions: 2.0.0-alpha, 1.0.0
Reporter: Junping Du
Assignee: Junping Du
Priority: Critical
The current hadoop network topology (described in some previous issues like:
Hadoop-692) works well in classic three-tiers network when it comes out.
However, it does not take into account other failure models or changes in the
infrastructure that can affect network bandwidth efficiency like:
virtualization.
Virtualized platform has following genes that shouldn't been ignored by hadoop
topology in scheduling tasks, placing replica, do balancing or fetching block
for reading:
1. VMs on the same physical host are affected by the same hardware failure. In
order to match the reliability of a physical deployment, replication of data
across two virtual machines on the same host should be avoided.
2. The network between VMs on the same physical host has higher throughput and
lower latency and does not consume any physical switch bandwidth.
Thus, we propose to make hadoop network topology extend-able and introduce a
new level in the hierarchical topology, a node group level, which maps well
onto an infrastructure that is based on a virtualized environment.
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