[DOC]: Clarify self-signed certs in security config

[Franz-Ritter]

What do you want to do?

• [ x] Request a change to existing documentation
• [ ] Add new documentation
• [ ] Report a technical problem with the documentation
• [ ] Other

Tell us about your request. Provide a summary of the request and all versions that are affected.

I tried to enable https by creating a self signed certificate as described in https://opensearch.org/docs/latest/security/configuration/generate-certificates/ However, after I configured by docker-compose to use the certificates and the properties described on this page, my dashboard node reponde with the errors:

{"type":"log","@timestamp":"20xx-xx-xxTxx:xx:xxZ","tags":["error","opensearch","data"],"pid":1,"message":"[ConnectionError]: self signed certificate"}

After comparing the default configuration file opensearch_dashboards.yml on the image from opensearchproject/opensearch-dashboards I realized that the confi has the property server.host: '0.0.0.0' defined, which was missing in the example on this page. Ading this information solved my problem. Therefore, I would suggest to add this property to the documentation

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.

[cwillum]

@Franz-Ritter Thanks for raising this issue. It clearly needs some attention. Could you give me a little more detail about these items:

1. Just for clarification: You found the server.host setting in opensearch_dashboards.yml from your image set to 0.0.0.0. And when you changed the setting value to match the same in the example opensearch_dashboards.yml file in the opensearchproject/opensearch-dashboards repo (which uses the value "localhost"), you got no error and were able to connect. Is that correct? (or the other way around: you changed the localhost value to 0.0.0.0 in your opensearch_dashboards.yml file?)
2. Are you certain the error is directly related to an implementation using the self-signed certificates? Did you try connect with the demo certificates (without getting an error)?
3. Is there a specific step/point in the current Generating self-signed certificates documentation where this new understanding about the server.host setting value would have helped avoid the original problem? Again, much appreciation for raising the issue.

[AntonEliatra]

@hdhalter I'll take this one

[hdhalter]

Thanks, @AntonEliatra ! @scrawfor99 - can you please sign off for technical accuracy? https://github.com/opensearch-project/documentation-website/pull/7134