When you configure X-Pack to monitor multiple Logstash instances make sure each instance has a unique uuid.
We copied AMIs in AWS to create multiple Logstash instances and all of the instances had the same uuid which confused the X-Pack monitoring server.
Change the uuid of a Logstash server:
- $ sudo -i
- # uuidgen > /var/lib/logstash/uuid
- # tr -d "\n\r" < /var/lib/logstash/uuid > tempo ; mv tempo /var/lib/logstash/uuid
- # service logstash restart