Description of problem:

# katello-remove -y

Starting removal

Stopping services

Removing RPMs

Cleaning up configuration files

Cleaning up log files

Cleaning up certs

Cleaning up content
/usr/share/ruby/fileutils.rb:1433:in `rmdir': Device or resource busy - /var/cache/pulp (Errno::EBUSY)
        from /usr/share/ruby/fileutils.rb:1433:in `block in remove_dir1'
        from /usr/share/ruby/fileutils.rb:1444:in `platform_support'
        from /usr/share/ruby/fileutils.rb:1432:in `remove_dir1'
        from /usr/share/ruby/fileutils.rb:1425:in `remove'
        from /usr/share/ruby/fileutils.rb:770:in `block in remove_entry'
        from /usr/share/ruby/fileutils.rb:1477:in `block (2 levels) in postorder_traverse'
        from /usr/share/ruby/fileutils.rb:1481:in `postorder_traverse'
        from /usr/share/ruby/fileutils.rb:1476:in `block in postorder_traverse'
        from /usr/share/ruby/fileutils.rb:1475:in `each'
        from /usr/share/ruby/fileutils.rb:1475:in `postorder_traverse'
        from /usr/share/ruby/fileutils.rb:768:in `remove_entry'
        from /usr/share/ruby/fileutils.rb:626:in `block in rm_r'
        from /usr/share/ruby/fileutils.rb:622:in `each'
        from /usr/share/ruby/fileutils.rb:622:in `rm_r'
        from /sbin/katello-remove:188:in `remove'
        from /sbin/katello-remove:231:in `<main>'


This following bugzilla doesn't fix the issue completely.

# katello-remove does not completely remove data on mounted filesystems
https://bugzilla.redhat.com/show_bug.cgi?id=1574257


I think the issue is in the codes below. It only checks whether "/var/cache" is a mounted directory or not, but it doesn't take the sub directories of "/var/cache/" into consideration.

# katello-remove
------------------------------
<snip>

CONTENT.map! do |dir|
  if File.readlines('/proc/mounts').any? { |line| line.split(' ')[1] =~ /#{dir}$/ }
    dir + '/*'
  else
    dir
  end
end

<snip>
-----------------------------

I think what it should do are:
1) Loop into the subdirectories of "/var/cache".
2) If any sub directory is a mounted directory then append it to the MOUNTS array.
3) If no mounted sub directories found in it then simply rm "/var/cache/*"