[jira] Commented: (HADOOP-435) Encapsulating startup scripts and jars in a single Jar file.

["Pete Wyckoff (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-435?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12617629#action_12617629 ] 

Pete Wyckoff commented on HADOOP-435:
-------------------------------------

I think we should re-do as many of the scripts as possible in Java. If possible all of them as this should get us out of the environment variable business, as all those things can now go into hadoop-site.xml/hadoop--default.xml.

I can take Ben's patch and use that as a starting point, but would propose:

1. replacing hadoop with hadoop-exe.jar which would mean checking for --confdir, figuring out the default conf dir, and grabbing things like the pidfile, logging dir,  and such from hadoop-site.xml and adding these to the main arguments before invoking the appropriate main method

2. re-implement hadoop-daemon(s).sh in java

Maybe leave start/stop-dfs/mapred/balancer as shell scripts for now.



> Encapsulating startup scripts and jars in a single Jar file.
> ------------------------------------------------------------
>
>                 Key: HADOOP-435
>                 URL: https://issues.apache.org/jira/browse/HADOOP-435
>             Project: Hadoop Core
>          Issue Type: New Feature
>    Affects Versions: 0.12.1
>            Reporter: Benjamin Reed
>             Fix For: 0.13.0
>
>         Attachments: hadoop-exe.patch, hadoop-exe.patch, hadoop-exe.patch, hadoop-exe.patch, hadoopit.patch, hadoopit.patch, hadoopit.patch, start.sh, stop.sh
>
>
> Currently, hadoop is a set of scripts, configurations, and jar files. It makes it a pain to install on compute and datanodes. It also makes it a pain to setup clients so that they can use hadoop. Everytime things are updated the pain begins again.
> I suggest that we should be able to build a single Jar file that has a Main-Class defined with the configuration built in so that we can distribute that one file to nodes and clients on updates. One nice thing that I haven't done would be to make the jarfile downloadable from the JobTracker webpage so that clients can easily submit the jobs.
> I currently use such a setup on my small cluster. To start the job tracker I used "java -jar hadoop.jar -l /tmp/log jobtracker" to submit a job I use "java -jar hadoop.jar jar wordcount.jar". I used the client on my linux and Mac OSX machines and I'll I need installed in java and the hadoop.jar file.
> hadoop.jar helps with logfiles and configurations. The default of pulling the config files from the jar file can be overridden by specifying a config directory so that you can easily have machine specific configs and still have the same hadoop.jar on all machines.
> Here are the available commands from hadoop.jar:
> USAGE: hadoop [-l logdir] command
>   User commands:
>     dfs          run a DFS admin client
>     jar          run a JAR file
>     job          manipulate MapReduce jobs
>     fsck         run a DFS filesystem check utility
>   Runtime startup commands:
>     datanode     run a DFS datanode
>     jobtracker   run the MapReduce job Tracker node
>     namenode     run the DFS namenode (namenode -format formats the FS)
>     tasktracker  run a MapReduce task Tracker node
>   HadoopLoader commands:
>     buildJar     builds the HadoopLoader jar file
>     conf         dump hadoop configuration
> Note, I don't have the classes for hadoop streaming built into this Jar file, but if I had that would also be an option (it checks for needed classes before displaying an option). It makes it very easy for users that just write scripts to use hadoop straight from their machines.
> I'm also attaching the start.sh and stop.sh scripts that I use. These are the only scripts I use to startup the daemons. They are very simple and the start.sh script uses the config file to figure out whether or not to start the jobtracker and the nameserver.
> The attached patch adds the HadoopIt patch, modifies the Configuration class to find the config files correctly, and modifies the build to make a fully contained hadoop.jar. To update the configuration in a hadoop.jar you simply use "zip hadoop.jar hadoop-site.xml".

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