`block in converge_state' when setting up output to gelf host

Hi,

Im getting this error:

[2022-09-21T11:32:55,738][FATAL][logstash.runner ] An unexpected error occurred! {:error=>#<LogStash::Error: Don't know how to handle Java::JavaLang::IllegalStateExceptionforPipelineAction::Create>, :backtrace=>["org/logstash/execution/ConvergeResultExt.java:129:in create'", "org/logstash/execution/ConvergeResultExt.java:57:in add'", "/usr/share/logstash/logstash-core/lib/logstash/agent.rb:378:in block in converge_state'"]}`

Running logstash 7.1.0 on Docker

logstash.conf

input {
  beats {
    port => 5044
  }
}
output {
   gelf {
      host => ["host.internal.domain"]
   }
}

The resources and topics i've found were about a missing "}" but as far i can see is not the case. The error seems to be in the last block of the output. Without it i wount get this error. Tried also "hostname" since the doc states a string.

Some help much appreciated.

Thanks!

I will close this issue. The output plugins are extra packages that also needs to be installed. I will try to implement this in my docker image/container and try again.