docs: Add note about v1.0 addr behaviour

[charlieegan3]

Fixes #7360

Also https://github.com/orgs/open-policy-agent/discussions/662#discussioncomment-12338962

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[anderseknert]

Perhaps worth explicitly calling out that this is likely necessary when running OPA in Docker?

[charlieegan3]

Thanks, I've added an info block for that now

[srenatus]

nitpick aside, lgtm

[srenatus]

[nit] Should this be a relevant....no, a relative link? Or can't we do that with # anchors? 🤔

[charlieegan3]

Yeah that's fair, I have updated.

[liqiongbu]

@charlieegan3 I am having issue when migrating to v1 #7735
My guess is that the -addr behavior changed from v0 to v1 since we used to always set -addr to localhost:8181
Could you help me confirm on this? Should we update the config to -addr 0.0.0:8181 to make v1 migration work? Thanks!

[anderseknert]

@liqiongbu yeah, a pretty common issue people run into when bumping OPA to 1.0+ is that from 1.0 and onwards, OPA's server now only binds to the localhost interface by default, where it precvously would bind to all interfaces. Docker doesn't seem too happy about exposing localhost to the outside, which typically manifests in the way you describe.

What I don't understand why there is a difference if you start both versions with localhost explicitly set as the netwokr interface. That should break the same way in any version. We only changed the default when nothing is provided.

[liqiongbu]

This is also where I get confusions from, since we always explicitly set addr, I should expect I don't have to overwrite this in v1 migration
Some context to note:
1, we use nomad deployment
2, opa is set as sidecar
3,I'd love to provide more config info if that helps with this issue

[liqiongbu]

I think I linked the wrong issue, here is the one: #7735

[charlieegan3]

Hey @liqiongbu - let's continue the chat on the new issue! 🙂