Affects Version/s: sprint-1
Fix Version/s: None
Currently in Ignite we have setup-hadoop script + java class to replace configs and create symlinks to Ignite libraries.
This setup script and Ignite launcher script have many dependencies on the Hadoop distribution layout (files, configs, etc.)
I suggest to simplify this:
1) It seems to me that no symlink and/or library copying needed at all. Instead, to make hadoop client work via Ignite, we can use the following wrapper around the default hadoop client launcher script:
file "hadoop-ignited" :
is folder inside IGNITE distribution where the 2 custom configs are located: core-site.xml, mapred-site.xml .
(If the user wants only Ignite MapRed engine, but does not need Ignite filesystem, he symlinks the default mapred-site.xml in this directory.)
This way, in order to use fully pre-configured Hadoop cluster the user only needs to add "hadoop-ignited" script into PATH.
After that instead of running hadoop jar examples.jar pi 10 10 , use can run hadoop-ignited jar examples.jar pi 10 10 to run the sample on fully ignited Hadoop.
2) The only thing that is still needs attention is how the Ignite node should find the Hadoop libraries. My suggestion is to provide 3 versions of config scripts depending on the supported layouts, like "layout-apache", "layout-cloudera", and "layout-bigtop-hortonworks" (I suppose, the latter 2 are identical) . After that ask use after Ignite archive unzipping write 1 line into startup script, like LAYOUT=cloudera, and that's it – the corresponding env script will be picked up to set up env variables needed by the user's Hadoop distribution.
(Earlier attempt to solve this problem described in https://issues.apache.org/jira/browse/IGNITE-372 .)
This approach works with Hive as well.