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https://issues.apache.org/jira/browse/HADOOP-8198?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13251617#comment-13251617
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Daryn Sharp commented on HADOOP-8198:
-------------------------------------
As Eli alluded to, I have been trying to formulate a more sustainable model for
mapping tokens to their host. The current token service model is rapidly
breaking with the advent of features like HA and multi-interface hosts. The
use of ip service (ip:port) provides no portability of tokens. Using
host-based tokens (host:port) provides portability when a host's ip changes.
HA and multi-interface hosts create a larger challenge that host-based tokens
do not address. HA currently rewrites the service of a fetched token to an
abstract identifier. The token is later duplicated and the service is
rewritten to each of the HA NN's services. This approach only works if all
clients are identically configured. Cross-colo access requires all grids to
share configurations which becomes a difficult maintenance issue.
Multi-interface hosts would require the same concept of HA - an abstract
identifier - but the client cannot chose the identifier w/o further complicated
config settings. What I'd like to propose is the client no longer manages the
service of a token. The server will set the service to an abstract id for
itself. The id will be presented in the SASL challenge. The client will chose
the token based on the id. This approach would neatly solve the dichotomy
between ips/hosts/HA/multi-interface.
Whether multi-interface support is added, I think the token service model needs
to be evolved because it's becoming fragile and relying too much on the client
to manage the service correctly. I'll create another jira and write up a
design proposal as soon as I get a chance.
> Support multiple network interfaces
> -----------------------------------
>
> Key: HADOOP-8198
> URL: https://issues.apache.org/jira/browse/HADOOP-8198
> Project: Hadoop Common
> Issue Type: New Feature
> Components: io, performance
> Reporter: Eli Collins
> Assignee: Eli Collins
> Attachments: MultipleNifsv1.pdf, MultipleNifsv2.pdf,
> MultipleNifsv3.pdf
>
>
> Hadoop does not currently utilize multiple network interfaces, which is a
> common user request, and important in enterprise environments. This jira
> covers a proposal for enhancements to Hadoop so it better utilizes multiple
> network interfaces. The primary motivation being improved performance,
> performance isolation, resource utilization and fault tolerance. The attached
> design doc covers the high-level use cases, requirements, a proposal for
> trunk/0.23, discussion on related features, and a proposal for Hadoop 1.x
> that covers a subset of the functionality of the trunk/0.23 proposal.
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