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https://issues.apache.org/jira/browse/SPARK-632?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14206158#comment-14206158
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Andrew Ash commented on SPARK-632:
----------------------------------

// link moved to 
http://doc.akka.io/docs/akka/current/additional/faq.html#what-is-the-name-of-a-remote-actor

I believe having the hostname change case will still break Spark.  But after a 
search of the dev and user mailing lists over the past year I haven't seen any 
other users with this issue.

A potential fix could be to call .toLower on the hostname in the Akka string 
across the cluster, but it's a little dirty to make this assumption everywhere.

Technically [hostnames ARE case 
insensitive|http://serverfault.com/questions/261341/is-the-hostname-case-sensitive]
 so Spark's behavior is wrong, but the issue is in the underlying Akka library. 
 This is the same underlying behavior where Akka requires that hostnames 
exactly match as well -- you can't use an IP address to refer to a Akka 
listening on a hostname -- SPARK-625.

Until Akka handles differently-cased hostnames I think can only be done with an 
ugly workaround.

Possibly relevant Akka issues:
- https://github.com/akka/akka/issues/15990
- https://github.com/akka/akka/issues/15007

My preference would be to close this as "Won't Fix" until it's raised again as 
a problem from the community.

cc [~rxin]

> Akka system names need to be normalized (since they are case-sensitive)
> -----------------------------------------------------------------------
>
>                 Key: SPARK-632
>                 URL: https://issues.apache.org/jira/browse/SPARK-632
>             Project: Spark
>          Issue Type: Bug
>            Reporter: Matt Massie
>
> The "system" name of the Akka full path is case-sensitive (see 
> http://akka.io/faq/#what_is_the_name_of_a_remote_actor).
> Since DNS names are case-insensitive and we're using them in the "system" 
> name, we need to normalize them (e.g. make them all lowercase).  Otherwise, 
> users will find the "workers" will not be able to connect with the "master" 
> even though the URI appears to be correct.
> For example, Berkeley DNS occasionally uses names e.g. foo.Berkley.EDU. If I 
> used foo.berkeley.edu as the master adddress, the workers would write to 
> their logs that they are connecting to foo.berkeley.edu but failed to. They 
> never show up in the master UI.  If use the foo.Berkeley.EDU address, 
> everything works as it should. 



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