Add bach web portal page

[leochen4891]

The page is designed to provide:

1. Services and their port, e.g. namenode on 50070 and hbase on 16010
2. Useful links, e.g. namenode web UI page.
3. Files, e.g. conf page tool blacklist file.

Needs review, please don't merge.

also added a json end point "/json"

[http-418]

If you delete the entry entirely, the default is 80.

[leochen4891]

Updated and tested. Ready to review and merge.

[cbaenziger]

Hi @leochen4891, do you have any documentation the structure of the Apache file layout after this change?

My attempt to build Chef-BACH seems to be breaking due to an empty node['bach_web']['links']. In trying to fix it up I am not grokking why there is a second bach-web virtual host and bach.html.erb rather than overriding the default index.html.erb in the default virtual host with what we need?

Also, it seems links and files share the same structure; what do you see the difference in the two structures being used for?

[leochen4891]

The Apache files layout after this change is to keep bach_bach related files under /var/www/bach/, which contains a sub-dir "files" to expose files.

The reason I didn't override the existing index.html.erb and virtual host is that I was thinking of adding bach_web as a new set of pages, but not necessarily at the top level directory. I would have no objection if you suggest overriding existing index.html.erb and virtual host is a better way.

links and files are all jumps from user's point of view, but conceptually files has physical files sitting in /var/www/bach/files/ while a link can be anything jump-able. I think it should be fine to combine them into links if that would reduce some unneeded complexity.

[cbaenziger]

The next issue I hit was:

Recipe: bcpc-hadoop::hdfs_web
  * directory[/var/www/bach/files/hdfs] action create
    * Parent directory /var/www/bach/files does not exist, cannot create /var/www/bach/files/hdfs
    ================================================================================
    Error executing action `create` on resource 'directory[/var/www/bach/files/hdfs]'
    ================================================================================

    Chef::Exceptions::EnclosingDirectoryDoesNotExist
    ------------------------------------------------
    Parent directory /var/www/bach/files does not exist, cannot create /var/www/bach/files/hdfs

[leochen4891]

The dir /var/www/bach/files is created in bcpc::apache2 and should be prior to bcpc-hadoop::hdfs_web in the run_list.
Can you please take a look at the expanded run_list and check if bcpc-hadoop::hdfs_web is in front of bcpc::apache2 for some reason?

[leochen4891]

The cause of the missing directory is worker nodes doesn't need the xxxx_web recipes , and should be fixed by #1276