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https://issues.apache.org/jira/browse/KNOX-2054?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kevin Risden resolved KNOX-2054.
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Resolution: Duplicate
I'm looking at KNOX-843 and this jira is a duplicate of KNOX-843. It will
accomplish what was described here.
> Accomodate APIs with multiple endpoints
> ---------------------------------------
>
> Key: KNOX-2054
> URL: https://issues.apache.org/jira/browse/KNOX-2054
> Project: Apache Knox
> Issue Type: Improvement
> Reporter: Thomas Tauber-Marshall
> Priority: Major
>
> A service definition was recently added to support accessing Impala via
> Hiveserver2.
> One issue here is that Impala has historically generally used multiple
> "coordinators", nodes that can accept queries (originally, all nodes acted as
> both a coordinator and executor, though Impala has moved away from that to
> dedicated coordinators/executors recently for scalability reasons)
> In Knox, when you create a topology you can specify multiple urls for a
> single service, but my understanding is that Knox will only ever direct
> requests to one of those urls, unless it becomes unavailable and then another
> url will be choosen to direct all requests to.
> This poses a problem for Impala, as it makes it difficult to support multiple
> coordinators. Hive also has a similar problem.
> There are at least two ways to work around this currently in Knox with only
> configuration changes:
> - Users can set up multiple topologies, one for each Impala coordinator.
> - The Impala service definition can be modified to allow specifying a
> hostname to direct requests to, the way many UI service definitions allow
> "?host=..." parameter.
> Both of these are ugly hacks and a better solution is needed.
> One potential solution would be to add some sort of load balancing
> functionality to Knox. Then, if a service has multiple urls specified in the
> topology requests could be directed to any one of those urls transparently.
> One complication is that Impala clients would need to have sticky connections
> - session and query state is not shared between coordinators in Impala, so a
> client that connects to a particular coordinator would need to have all of
> their requests be directed to that same coordinator for the duration of their
> session.
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