After upgrading logstash 6.3.2 to 6.8.13 it doesn´t start. Looking into the log file shows:
[2021-01-09T11:24:12,770][DEBUG][logstash.modules.scaffold] Found module {:module_name=>"fb_apache", :directory=>"/products/elk/logstash/modules/fb_apache/configuration"}
[2021-01-09T11:24:12,770][DEBUG][logstash.plugins.registry] Adding plugin to the registry {:name=>"fb_apache", :type=>:modules, :class=>#<LogStash::Modules::Scaffold:0x62ae5180 @directory="/products/elk/logstash/modules/fb_apache/configuration", @module_name="fb_apache", @kibana_version_parts=["6", "0", "0"]>}
[2021-01-09T11:24:12,800][FATAL][logstash.runner ] An unexpected error occurred! {:error=>#<NameError: uninitialized constant LibC::FFI>, :backtrace=>["org/jruby/RubyModule.java:3742:in `const_missing'", "/products/elk/logstash-6.8.13/logstash-core/lib/logstash/util/prctl.rb:4:in `<module:LibC>'", "/products/elk/logstash-6.8.13/logstash-core/lib/logstash/util/prctl.rb:2:in `<main>'", "org/jruby/RubyKernel.java:987:in `require'", "/products/elk/logstash-6.8.13/vendor/bundle/jruby/2.5.0/gems/polyglot-0.3.5/lib/polyglot.rb:65:in `require'", "/products/elk/logstash-6.8.13/logstash-core/lib/logstash/util.rb:1:in `(root)'", "/products/elk/logstash-6.8.13/logstash-core/lib/logstash/util.rb:21:in `set_thread_name'", "/products/elk/logstash-6.8.13/logstash-core/lib/logstash/runner.rb:306:in `execute'", "/products/elk/logstash-6.8.13/vendor/bundle/jruby/2.5.0/gems/clamp-0.6.5/lib/clamp/command.rb:67:in `run'", "/products/elk/logstash-6.8.13/logstash-core/lib/logstash/runner.rb:237:in `run'", "/products/elk/logstash/lib/bootstrap/environment.rb:73:in `<main>'"]}
[2021-01-09T11:24:12,802][ERROR][org.logstash.Logstash ] java.lang.IllegalStateException: Logstash stopped processing because of an error: (SystemExit) exit
I copied the configuration from the 6.3.2 version to 6.8.13 version and changed the key words according the 6.8.13. guide...
I thougth upgrading minor versions should be an easy task.. 