3.5.7 now binds to localhost-only by default

[tianon]

We need to figure out a good way to handle https://jira.mongodb.org/browse/SERVER-28229 -- MongoDB as of 3.5.7 now binds to localhost-only (see also mongodb/mongo@60636b4).

There is a new --bind_ip_all flag, but it does pose complications similar to what we've got with our new initdb behavior around configuration files. 😞

[tianon]

It might be that we simply add --bind_ip_all to CMD, and leave this choice up to our users to make?

[yosifkit]

CMD seems fine, but gets annoying if I just want to add a flag:

$ docker run -d --name mongo mongo:3.5 --newflag
$ # can't connect :'(

Though it should be in the logs:

If no explicit bind_ip has been provided, print a startup warning indicating that the server is not responding to external connections, which describes how to fix the problem.

2017-05-18T21:07:13.857+0000 I CONTROL  [initandlisten] ** ATTENTION: The server is bound to localhost.
2017-05-18T21:07:13.857+0000 I CONTROL  [initandlisten] **          Remote systems will be unable to connect to this server. 
2017-05-18T21:07:13.857+0000 I CONTROL  [initandlisten] **          Start the server with --bind_ip <address> to specify which IP addresses it
2017-05-18T21:07:13.857+0000 I CONTROL  [initandlisten] **          should serve responses from, or with --bind_ip_all to bind to all interfaces.

[tianon]

Yeah, I guess the best we can do there is to update our docs once 3.6 officially drops to explicitly include --bind_ip_all in the couple places we add flags?

IMO it'll be easier for us to handle users doing that if we decide to push this logic into the docker-entrypoint.sh, since we'll have to handle that case regardless (given that users tend to do things we don't expect 😄).