fluentd does not restart children if they die

[dmnfortytwo]

2018-04-06 13:13:00 +0000 [warn]: #0 failed to write data into buffer by buffer overflow action=:throw_exception
2018-04-06 13:13:00 +0000 [warn]: #0 emit transaction failed: error_class=Fluent::Plugin::Buffer::BufferOverflowError error="can't create buffer metadata for /var/lib/td-agent/buffers/output_elasticsearch-7/buff$
r.*.log. Stop creating buffer files: error = Too many open files @ rb_sysopen - /var/lib/td-agent/buffers/output_elasticsearch-7/buffer.b5692dd0baff981007f92e2649ebfdbc3.log.meta" location="/opt/td-agent/embedde$
/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer/file_chunk.rb:294:in `rescue in create_new_chunk'" tag="fluent.info"
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer/file_chunk.rb:294:in `rescue in create_new_chunk'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer/file_chunk.rb:283:in `create_new_chunk'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer/file_chunk.rb:50:in `initialize'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buf_file.rb:163:in `new'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buf_file.rb:163:in `generate_chunk'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer.rb:530:in `block in write_once'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/2.4.0/monitor.rb:214:in `mon_synchronize'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer.rb:530:in `write_once'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer.rb:277:in `block in write'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer.rb:275:in `each'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer.rb:275:in `write'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/output.rb:967:in `block in handle_stream_simple'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/output.rb:851:in `write_guard'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/output.rb:966:in `handle_stream_simple'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/output.rb:841:in `execute_chunking'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/output.rb:771:in `emit_buffered'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/out_copy.rb:58:in `block in process'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/out_copy.rb:56:in `each'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/out_copy.rb:56:in `each_with_index'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/out_copy.rb:56:in `process'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/multi_output.rb:148:in `emit_sync'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/event_router.rb:159:in `emit_events'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/event_router.rb:96:in `emit_stream'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/event_router.rb:87:in `emit'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/engine.rb:207:in `block in log_event_loop'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/engine.rb:205:in `each'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/engine.rb:205:in `log_event_loop'
2018-04-06 13:13:00 +0000 [error]: #0 failed to emit fluentd's log event tag="fluent.info" event={"worker"=>0, "message"=>"fluentd worker is now running worker=0"} error_class=Fluent::Plugin::Buffer::BufferOverf$
owError error="can't create buffer metadata for /var/lib/td-agent/buffers/output_elasticsearch-7/buffer.*.log. Stop creating buffer files: error = Too many open files @ rb_sysopen - /var/lib/td-agent/buffers/out$
ut_elasticsearch-7/buffer.b5692dd0baff981007f92e2649ebfdbc3.log.meta"
2018-04-06 13:13:00 +0000 [warn]: #0 failed to flush the buffer. retry_time=0 next_retry_seconds=2018-04-06 13:13:10 +0000 chunk="5691a86c7266329a125a8f2f4a31216d" error_class=NoMethodError error="undefined meth$
d `downcase' for #<Array:0x00007f53f1562a10>"
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluent-plugin-elasticsearch-2.4.0/lib/fluent/plugin/out_elasticsearch.rb:379:in `block in write'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/event.rb:323:in `each'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/event.rb:323:in `block in each'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer/file_chunk.rb:170:in `open'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/event.rb:322:in `each'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluent-plugin-elasticsearch-2.4.0/lib/fluent/plugin/out_elasticsearch.rb:340:in `write'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/output.rb:1093:in `try_flush'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/output.rb:1318:in `flush_thread_run'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/output.rb:439:in `block (2 levels) in start'
  2018-04-06 13:13:00 +0000 [warn]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin_helper/thread.rb:78:in `block in thread_create'
2018-04-06 13:13:01 +0000 [warn]: #0 failed to write data into buffer by buffer overflow action=:throw_exception
2018-04-06 13:13:01 +0000 [warn]: #0 emit transaction failed: error_class=Fluent::Plugin::Buffer::BufferOverflowError error="can't create buffer metadata for /var/lib/td-agent/buffers/output_elasticsearch-7/buffe
r.*.log. Stop creating buffer files: error = Too many open files @ rb_sysopen - /var/lib/td-agent/buffers/output_elasticsearch-7/buffer.b5692dd0c882c3b11f2a767066ba06050.log.meta" location="/opt/td-agent/embedded
/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/buffer/file_chunk.rb:294:in `rescue in create_new_chunk'" tag="fluent.warn"
  2018-04-06 13:13:01 +0000 [warn]: #0 suppressed same stacktrace
2018-04-06 13:13:01 +0000 [error]: #0 failed to emit fluentd's log event tag="fluent.warn" event={"retry_time"=>0, "next_retry_seconds"=>"2018-04-06 13:13:10 +0000", "chunk"=>"5691a86c7266329a125a8f2f4a31216d", "
error"=>"#<NoMethodError: undefined method `downcase' for #<Array:0x00007f53f1562a10>>", "message"=>"failed to flush the buffer. retry_time=0 next_retry_seconds=2018-04-06 13:13:10 +0000 chunk=\"5691a86c7266329a1
25a8f2f4a31216d\" error_class=NoMethodError error=\"undefined method `downcase' for #<Array:0x00007f53f1562a10>\""} error_class=Fluent::Plugin::Buffer::BufferOverflowError error="can't create buffer metadata for 
/var/lib/td-agent/buffers/output_elasticsearch-7/buffer.*.log. Stop creating buffer files: error = Too many open files @ rb_sysopen - /var/lib/td-agent/buffers/output_elasticsearch-7/buffer.b5692dd0c882c3b11f2a76
7066ba06050.log.meta"
2018-04-06 13:13:01 +0000 [warn]: #0 thread exited by unexpected error plugin=Fluent::Plugin::ForwardInput title=:event_loop error_class=LoadError error="library not found for class Digest::SHA512 -- digest/sha2.
so"
2018-04-06 13:13:01 +0000 [error]: #0 unexpected error error_class=LoadError error="library not found for class Digest::SHA512 -- digest/sha2.so"
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/2.4.0/digest.rb:16:in `const_missing'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/in_forward.rb:422:in `check_ping'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/in_forward.rb:200:in `block in handle_connection'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/in_forward.rb:248:in `block (3 levels) in read_messages'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/in_forward.rb:247:in `feed_each'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/in_forward.rb:247:in `block (2 levels) in read_messages'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin/in_forward.rb:256:in `block in read_messages'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin_helper/server.rb:739:in `on_read_without_connection'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/cool.io-1.5.3/lib/cool.io/io.rb:123:in `on_readable'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin_helper/server.rb:711:in `on_readable'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/cool.io-1.5.3/lib/cool.io/io.rb:186:in `on_readable'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/cool.io-1.5.3/lib/cool.io/loop.rb:88:in `run_once'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/cool.io-1.5.3/lib/cool.io/loop.rb:88:in `run'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin_helper/event_loop.rb:84:in `block in start'
  2018-04-06 13:13:01 +0000 [error]: #0 /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/plugin_helper/thread.rb:78:in `block in thread_create'
2018-04-06 13:13:01 +0000 [error]: #0 library not found for class Digest::SHA512 -- digest/sha2.so path=nil error_class=LoadError error="library not found for class Digest::SHA512 -- digest/sha2.so"
  2018-04-06 13:13:01 +0000 [error]: #0 suppressed same stacktrace
2018-04-06 13:13:01 +0000 [info]: Worker 0 finished unexpectedly with status 2
2018-04-06 13:13:01 +0000 [info]: Received graceful stop

Other children are working, this is still a zombie. (Actually, there are two more zombies)

root@harvester-gce-eu-1:/var/log/td-agent# ps auxww | fgrep td-agent
root      1406  0.0  0.0   6536   728 pts/0    S+   09:26   0:00 fgrep --color=auto td-agent
td-agent  2470  0.0  0.0 130136 33972 ?        Sl   Apr05   1:27 /opt/td-agent/embedded/bin/ruby /usr/sbin/td-agent --log /var/log/td-agent/td-agent.log --daemon /var/run/td-agent/td-agent.pid
td-agent  2476  0.0  0.0 132184 35540 ?        Sl   Apr05   1:26 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /usr/sbin/td-agent --log /var/log/td-agent/td-agent.log --daemon /var/run/td-agent/td-agent.pid --under-supervisor
td-agent  2517  0.0  0.0 138848 41836 ?        Sl   Apr05   1:28 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_12.conf --log /var/log/td-agent/child_12.log
td-agent  2521 15.1  0.1 1652472 120748 ?      Sl   Apr05 852:08 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_12.conf --log /var/log/td-agent/child_12.log --under-supervisor
td-agent  2523  0.0  0.0 140896 42676 ?        Sl   Apr05   1:33 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_11.conf --log /var/log/td-agent/child_11.log
td-agent  2531 15.3  0.4 1734392 258952 ?      Sl   Apr05 860:07 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_11.conf --log /var/log/td-agent/child_11.log --under-supervisor
td-agent  2533  0.0  0.0      0     0 ?        Z    Apr05   0:25 [ruby] <defunct>
td-agent  2549  0.0  0.0      0     0 ?        Z    Apr05   0:28 [ruby] <defunct>
td-agent  2559  0.0  0.0 138848 41808 ?        Sl   Apr05   1:30 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_8.conf --log /var/log/td-agent/child_8.log
td-agent  2566 15.4  0.3 1687288 190764 ?      Sl   Apr05 865:19 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_8.conf --log /var/log/td-agent/child_8.log --under-supervisor
td-agent  2570  0.0  0.0      0     0 ?        Z    Apr05   0:25 [ruby] <defunct>
td-agent  2582  0.0  0.0 140896 36216 ?        Sl   Apr05   1:32 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_6.conf --log /var/log/td-agent/child_6.log
td-agent  2590 15.5  0.3 2739960 226796 ?      Sl   Apr05 873:34 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_6.conf --log /var/log/td-agent/child_6.log --under-supervisor
td-agent  2592  0.0  0.0 138848 35712 ?        Sl   Apr05   1:32 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_5.conf --log /var/log/td-agent/child_5.log
td-agent  2600 15.8  0.2 8972024 127700 ?      Sl   Apr05 888:41 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_5.conf --log /var/log/td-agent/child_5.log --under-supervisor
td-agent  2602  0.0  0.0 138848 32352 ?        Sl   Apr05   1:38 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_4.conf --log /var/log/td-agent/child_4.log
td-agent  2625 15.5  0.2 1699576 166152 ?      Sl   Apr05 876:07 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_4.conf --log /var/log/td-agent/child_4.log --under-supervisor
td-agent  2627  0.0  0.0      0     0 ?        Z    Apr05   0:24 [ruby] <defunct>
td-agent  2653  0.0  0.0 138848 29928 ?        Sl   Apr05   1:38 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_2.conf --log /var/log/td-agent/child_2.log
td-agent  2660 15.5  0.4 5836536 278052 ?      Sl   Apr05 875:39 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_2.conf --log /var/log/td-agent/child_2.log --under-supervisor
td-agent  2664  0.0  0.0 138848 29908 ?        Sl   Apr05   1:39 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_1.conf --log /var/log/td-agent/child_1.log
td-agent  2672 15.6  0.4 3825400 260256 ?      Sl   Apr05 877:34 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_1.conf --log /var/log/td-agent/child_1.log --under-supervisor
td-agent  2680  0.0  0.0 146020 32984 ?        Sl   Apr05   1:40 /opt/td-agent/embedded/bin/ruby /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_0.conf --log /var/log/td-agent/child_0.log
td-agent  2687  0.5  0.1 280240 74048 ?        Sl   Apr05  32:54 /opt/td-agent/embedded/bin/ruby -Eascii-8bit:ascii-8bit /opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb -c /etc/td-agent/child_0.conf --log /var/log/td-agent/child_0.log --under-supervisor

My master config:

<source>
  @type multiprocess
  <process>
    cmdline -c /etc/td-agent/child_0.conf --log /var/log/td-agent/child_0.log
    sleep_before_start 1s
    sleep_before_shutdown 5s
  </process>
  <process>
    cmdline -c /etc/td-agent/child_1.conf --log /var/log/td-agent/child_1.log
    sleep_before_start 1s
    sleep_before_shutdown 5s
  </process>
...
  <process>
    cmdline -c /etc/td-agent/child_12.conf --log /var/log/td-agent/child_12.log
    sleep_before_start 1s
    sleep_before_shutdown 5s
  </process>
</source>

My versions:

2018-03-28 19:46:33 +0000 [info]: starting fluentd-1.0.2 pid=22210 ruby="2.4.2"
2018-03-28 19:46:33 +0000 [info]: spawn command to main:  cmdline=["/opt/td-agent/embedded/bin/ruby", "-Eascii-8bit:ascii-8bit", "/opt/td-agent/embedded/lib/ruby/gems/2.4.0/gems/fluentd-1.0.2/lib/fluent/command/fluentd.rb", "-c", "/etc/td-agent/child_7.conf", "--log", "/var/log/td-agent/child_7.log", "--under-supervisor"]
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-elasticsearch' version '2.4.0'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-flowcounter' version '1.3.0'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-kafka' version '0.6.5'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-multiprocess' version '0.2.2'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-prometheus' version '1.0.1'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-rewrite-tag-filter' version '2.0.1'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-s3' version '1.1.0'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-td' version '1.0.0'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-td-monitoring' version '0.2.3'
2018-03-28 19:46:34 +0000 [info]: gem 'fluent-plugin-webhdfs' version '1.2.2'
2018-03-28 19:46:34 +0000 [info]: gem 'fluentd' version '1.0.2'