Change default APM server_url to 'http://127.0.0.1:8200' to avoid IPv6 ambiguity

[trentm]

Description

The current default APM server URL -- 'http://localhost:8200/' -- is ambiguous. "localhost" can resolve to a '127.0.0.1' (IPv4) or '[::1]' (IPv6), or possibly other custom-added IP addresses. The spec has been changed to require http://127.0.0.1:8200 be the default server_url.

Agent Issues

• [x] https://github.com/elastic/apm-agent-nodejs/pull/3049
• [ ] https://github.com/elastic/apm-agent-java/issues/2925
• [ ] https://github.com/elastic/apm-agent-dotnet/issues/1951
• [ ] https://github.com/elastic/apm-agent-python/issues/1712
• [ ] https://github.com/elastic/apm-agent-go/issues/1362
• [ ] https://github.com/elastic/apm-agent-php/issues/838
• [ ] https://github.com/elastic/apm-agent-ruby/issues/1332

Other places to update

(Not sure if I should make separate issues for each of these.)

• [ ] Kibana: https://github.com/search?q=repo%3Aelastic%2Fkibana+%22localhost%3A8200%22&type=code
• [ ] Hits for 'localhost:8200' in these repos:

  1 apm
  1 apm-contrib
  1 hey-apm
  1 kibana-load-testing
  1 observability-test-environments
  2 apm-dev
  2 elasticsearch-py
  2 opbeans-dotnet
  3 apm-aws-lambda
  3 observability-dev
  4 apm-integration-testing
  4 opbeans-node
  8 observability-docs

[SylvainJuge]

Is that required to change all occurrences of localhost:8200 to 127.0.0.1 in agent documentation also ? Or does just changing the default in agent configuration should be enough ?

[trentm]

Is that required to change all occurrences of localhost:8200 to 127.0.0.1 in agent documentation also ?

I think changing the docs would be good (at least where the server_url config var is documented) to be clear and avoid possible confusion, but I don't think it is likely to cause a problem. Is changing that a large amount of work in some areas? I don't want to create a make-work project.

[SylvainJuge]

Thanks, I'll update the java agent docs for consistency then, a simple sed s/localhost:8200/127.0.0.1:8200/g should be enough in most cases.

[SylvainJuge]

I forgot to mention that there are also a few references in Kibana (at least for the agent setup instructions) : https://github.com/search?q=repo%3Aelastic%2Fkibana+%22localhost%3A8200%22&type=code

[trentm]

I forgot to mention that there are also a few references in Kibana

@SylvainJuge Thanks! I've added some checkboxes to the description to look into update those (and some other hits I found).