Fluentd does not die sometimes (stuck on shutdown).
I dumped the ruby backtrace using sigdump. The result is attached at gistfile2.txt. Below is a part of it.
Thread #<Thread:0x00000001df50d8> status=sleep priority=0
/usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.43/lib/fluent/plugin/out_forward.rb:118:in `shutdown'
/usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluent-plugin-keep-forward-0.1.2/lib/fluent/plugin/out_keep_forward.rb:34:in `shutdown'
/usr/lib64/fluent/ruby/lib/ruby/gems/1.9.1/gems/fluentd-0.10.43/lib/fluent/plugin/out_copy.rb:56:in `block in shutdown'