fleet-server username/password authentication must be removed in 8.0

[jlind23]

Describe the enhancement:
Write access to Elasticsearch using username/password must be totally removed.

Describe a specific use case for the enhancement or feature:

[elasticmachine]

Pinging @elastic/elastic-agent-control-plane (Team:Elastic-Agent-Control-Plane)

[ruflin]

It needs to be made sure also all the related code in Elastic Agent is removed too.

[michel-laterman]

username/password has been removed from the fleet-server and elastic-agent in 8.1 and backported to 8.0.
The docs pr for this is: elastic/observability-docs#1423

[dikshachauhan-qasource]

Hi @jlind23

We have validated this ticket on 8.0 rc1 BC1 build self managed environment and found it working fine there.

Steps included:

• Set up a self managed env on 8.0 rc1 bc1 build.
• Access Kibana and install Fleet server agent under Default fleet server policy.
• Wait agent to be available on Fleet and running as Healthy.
• Now access location: C:\Program Files\Elastic\Agent and open Fleet.yml file
• Scroll down to outputs section.

Observation:

• No username and password key were available in Fleet.yml under output section.
• Service token value was available.

output:
      elasticsearch:
        protocol: https
        hosts:
        - 10.0.7.38:9200
        service_token: AAEAAWVsYXN0aWMvZmxlZXQtc2VydmVyL3Rva2VuLTE2NDE5MDAzNTk1NjA6SXZ4d29zSnZTY0M5a3kxbVFoalItQQ

Screenshot:

Build details:

BUILD 48917
COMMIT 51f4ded427abb6fd96c7d65e179fb367d450448c
Artifact link: https://staging.elastic.co/8.0.0-rc1-da1f5893/summary-8.0.0-rc1.html

Thanks
QAS