juju/utils/GetAddressesForInterface only returns IPv4 addresses

[John A Meinel]

LXD cannot be configured to support IPv6 addresses at the moment.

'juju bootstrap ... lxd' uses functionality to pass an address to the containers for what IP address they should contact. It uses github.com/juju/utils GetAddressForInterface("lxdbr0")
However that function calls GetIPv4Addresses() thus will only return an IPv4 address.

[John A Meinel (jameinel)]

This may not affect LXD containers but it definitely impacts the LXD provider.

[Anastasia (anastasia-macmood)]

Removing 2.1 milestone as we will not be addressing this issue in 2.1.

[Anastasia (anastasia-macmood)]

@John A Meinel (jameinel) ,

So what is the correct solution here?

1. To get lxd provider (provider/lxd/server.go) to call juju/utils/network.go.GetV4orV6AddressForInterface()

or

2. To change GetAddressForInterface() to try to get IPv4 but if not there to return IPv6? i.e. making the call to support IPv6 as well?

[Joseph Phillips (manadart)]

I think part of the eventual solution would be to use `GetV4orV6AddressForInterface`.

But container networking (see container/lxd/network.go) is set up to ensure that the LXD bridge only uses IPv4, so a controller inside a container could not access the service via IPv6 anyway.

[John A Meinel (jameinel)]

So the goal with this bug is to denote that we shouldn't *need* to disallow IPv6. Probably we need to watch out for Dual Stack (both V4 and V6 at the same time would probably confuse us, but there isn't any reason to think that we couldn't handle v6 everywhere.)
Having GetAddressForInterface handle 4 or 6 would be the best, and getting rid of the "must not have v6" in the container networking code.

[Canonical Juju QA Bot (juju-qa-bot)]

This bug has not been updated in 2 years, so we're marking it Low importance. If you believe this is incorrect, please update the importance.

[Federico Bosi (rhxto)]

I'm having this issue in an ipv6 only environment. I agree with @jameinel, there's no reason for any code to exclude ipv6 forcibly like this. Though it would require some extra work when ensuring consistency in dual stack environments.