[jira] [Commented] (HADOOP-8232) Provide a command line entry point to view/test topology options

["Steve Loughran (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-8232?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13893797#comment-13893797 ] 

Steve Loughran commented on HADOOP-8232:
----------------------------------------

we should be able to emit .dot files for graphviz rendering

> Provide a command line entry point to view/test topology options
> ----------------------------------------------------------------
>
>                 Key: HADOOP-8232
>                 URL: https://issues.apache.org/jira/browse/HADOOP-8232
>             Project: Hadoop Common
>          Issue Type: Sub-task
>          Components: util
>    Affects Versions: 0.23.1
>            Reporter: Steve Loughran
>            Assignee: Steve Loughran
>            Priority: Minor
>         Attachments: HADOOP-8232.patch, HADOOP-8232.patch
>
>
> Add a new command line entry point "topo" with commands for preflight checking of a clusters topology setup. 
> The initial operations would be to list the implementation class of the mapper, and attempt to load it, resolve a set of supplied hostnames, then dump the topology map after the resolution process.
> Target audience: 
> # ops teams trying to get a new/changed script working before deploying it on a cluster.
> # someone trying to write their first script.
> Resolve and list the rack mappings of the given host
> {code}
> hadoop topo test [host1] [host2] ... 
> {code}
> This would load the hostnames from a given file, resolve all of them and list the results:
> {code}
> hadoop topo testfile filename
> {code}
>  This version is intended for the ops team who have a list of hostnames, IP addresses. 
> * Rather than just list them, the ops team may want to mandate that there were no /default-rack mappings found, as that is invariably a sign that the script isn't handling a hostname properly.
> * No attempt to be clever and do IP address resolution, FQDN to hostname mapping, etc.



--
This message was sent by Atlassian JIRA
(v6.1.5#6160)