AWS instances created by juju don't have an IPv6 assigned, even if "auto-assign IPv6 addresses" is enabled for the subnet

[Junien F]

Hi,

When creating AWS instances with juju, even if I have enabled auto-assignment of IPv6 addresses in all my subnets, the instances don't have an IPv6 assigned to them.

To reproduce :
 - make sure that your VPC (default or not, if it's not the default, you'll have to bootstrap with "--config vpc-id=$vpc) has an IPv6 CIDR
 - make sure that all the subnets of the VPC have an IPv6 CIDR
 - make sure that all the subnets have "auto-assign IPv6" enabled

Then, bootstrap.

Result : the instance doesn't have an IPv6 assigned, and I need to assign one from the console (or using the API/CLI), and only then will dhclient -6 do the right thing.

Expected result : the instance is at least assigned an IPv6 in the management console. For the instance to do dhcp itself, I think we'll need cloud-init / UserData to be told so.

Also, the secgroups created by juju only have IPv4 rules. And, finally, the default routing table created by Amazon doesn't have a default gateway for IPv6 (you'll want to add one for ::/0, using the same igw as IPv4).

This is with juju 2.2-beta4. I couldn't find anything related to this in the debug output of "juju bootstrap".

Thanks

[Thomas Cuthbert (tcuthbert)]

This has affected us deploying dualstack services so it would be good if it received more priority.

[John A Meinel (jameinel)]

Enabling ipv6 on AWS is not in our immediate plans. if it is a blocker for people we can look to prioritize it but it mean interrupting other work. It doesn't sound like a quick fix (knowing when the subnet has ipv6, setting start instance flags, and updating information to cloud init).
AIUI there is quite a bit of complexity from AWS side (something about doing a v4 DHCP first, then reading metadata, then triggering *another* dhcp6 request.

[Haw Loeung (hloeung)]

For this, we're working around it with the AWS CLI commands below:

| aws ec2 assign-ipv6-addresses --network-interface-id $eni --ipv6-address-count 1

Then updating /e/n/i with 'auto ethX\niface ethX inet6 dhcp'.

[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.

[Haw Loeung (hloeung)]

I feel like IPv6-related tickets should probably have an importance/priority bump.

[Haw Loeung (hloeung)]

Any chance we could take a look at this? As IPv4 IPs are exhausted, more and more VMs are provisioned with IPv6 so we'll want Juju to improve IPv6 support.

[Seth Arnold (seth-arnold)]

This is indirectly causing reputational damage to Ubuntu; among my circle of friends I've seen references to Canonical and Ubuntu being far behind the times because our archive front ends in the clouds don't have IPv6. I understand that this is on the chain of features needed to make that happen.

Thanks

[Thomas Miller (tlmiller)]

We have submitted the following PR to address this bug https://github.com/juju/juju/pull/16061