Fleet Agent: Logstash output: Invalid version of beats protocol

Elastic Stack Beats
12

I will summarize my weekend here, let me know If I'm making any imprecision.

  1. TLS (ssl => true) is mandatory, if you set ssl to false you will receive bad protocol errors
  2. You can create one certificate and use the same in Fleet, and in Logstash. The docs suggest to create 2: one for client (Fleet), one for server (Logstash). The Logstash one must have --ip or --dns set. The client one can omit those.
  3. The logstash hostname (what you set in Fleet hosts) must match with what you configure under --dns or --ip in the certificate or you will receive "bad certificate" error <= this is the root cause of the error, I wasnt setting --dns