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https://issues.apache.org/jira/browse/HADOOP-9640?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13844743#comment-13844743
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Chris Li commented on HADOOP-9640:
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bq. Add a new configuration in common called "hadoop.application.context" to
HDFS. Other services that want to do the same thing can either use this same
configuration and find another way to configure it. This information should be
marshalled from the client to the server. The congestion control can be built
based on that.
Just to be clear, would an example be,
1. Cluster operator specifies ipc.8020.application.context = hadoop.yarn
2. Namenode sees this, knows to load the class that generates job IDs from the
Connection/Call?
Or were you thinking of physically adding the id into the RPC call itself,
which would make the rpc call size larger, but is a cleaner solution (albeit
one that the client could spoof).
bq. Lets also make identities used for accounting configurable. They can be
either based on "context", "user", "token", or "default". That way people who
do not like the default configuration can make changes.
Sounds like a good idea.
> RPC Congestion Control with FairCallQueue
> -----------------------------------------
>
> Key: HADOOP-9640
> URL: https://issues.apache.org/jira/browse/HADOOP-9640
> Project: Hadoop Common
> Issue Type: Improvement
> Affects Versions: 3.0.0, 2.2.0
> Reporter: Xiaobo Peng
> Labels: hdfs, qos, rpc
> Attachments: MinorityMajorityPerformance.pdf,
> NN-denial-of-service-updated-plan.pdf, faircallqueue.patch,
> faircallqueue2.patch, faircallqueue3.patch, faircallqueue4.patch,
> faircallqueue5.patch, rpc-congestion-control-draft-plan.pdf
>
>
> Several production Hadoop cluster incidents occurred where the Namenode was
> overloaded and failed to respond.
> We can improve quality of service for users during namenode peak loads by
> replacing the FIFO call queue with a [Fair Call
> Queue|https://issues.apache.org/jira/secure/attachment/12616864/NN-denial-of-service-updated-plan.pdf].
> (this plan supersedes rpc-congestion-control-draft-plan).
> Excerpted from the communication of one incident, “The map task of a user was
> creating huge number of small files in the user directory. Due to the heavy
> load on NN, the JT also was unable to communicate with NN...The cluster
> became responsive only once the job was killed.”
> Excerpted from the communication of another incident, “Namenode was
> overloaded by GetBlockLocation requests (Correction: should be getFileInfo
> requests. the job had a bug that called getFileInfo for a nonexistent file in
> an endless loop). All other requests to namenode were also affected by this
> and hence all jobs slowed down. Cluster almost came to a grinding
> halt…Eventually killed jobtracker to kill all jobs that are running.”
> Excerpted from HDFS-945, “We've seen defective applications cause havoc on
> the NameNode, for e.g. by doing 100k+ 'listStatus' on very large directories
> (60k files) etc.”
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