Bug 2092459

Summary:	IPv6-enabled EC2 subnets always have dhcp enabled
Product:	[Fedora] Fedora	Reporter:	Major Hayden 🤠 <mhayden>
Component:	cloud-init	Assignee:	Major Hayden 🤠 <mhayden>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	rawhide	CC:	adimania, apevec, dustymabe, eterrell, gholms, lars, rominf, shardy, s
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
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Fixed In Version:	cloud-init-23.1.2-7.fc39	Doc Type:	If docs needed, set a value
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Clone Of:		Environment:
Last Closed:	2023-05-17 13:36:11 UTC	Type:	Bug
Regression:	---	Mount Type:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Major Hayden 🤠 2022-06-01 15:28:42 UTC

A Fedora user opened an issue[0] about an issue with cloud-init on EC2. When they launch an instance on a IPv6-enabled subnet, cloud-init sets the `ipv6.method` to `dhcp` in NetworkManager.

However, AWS uses router advertisements to let instances know about the nearest router. Using the `ipv6.method: dhcp` setting prevents router advertisements from working. The instance ends up with an IPv6 address assigned, but it cannot route traffic.

A workaround is to run NetworkManager commands to fix the issue:

```
nmcli con edit CONNECTION_UUID
nmcli> set ipv6.method auto
nmcli> save
nmcli> activate
```

The instance immediately routes IPv6 traffic after making that change. The dhcp setting appears to be applied automatically for EC2 subnets with IPv6 addresses assigned[1].

I would expect `ipv6.method` to be `auto` in these situations.

Thank you!

[0] https://pagure.io/cloud-sig/issue/382
[1] https://github.com/canonical/cloud-init/blob/53a995e2f852d043d51ad25c1b9afbbe1edafd57/cloudinit/sources/DataSourceEc2.py#L861-L863

Comment 1 Ben Cotton 2022-08-09 13:17:10 UTC

This bug appears to have been reported against 'rawhide' during the Fedora Linux 37 development cycle.
Changing version to 37.

Comment 2 Major Hayden 🤠 2023-03-28 21:15:28 UTC

Still waiting on upstream to fix this here: https://bugs.launchpad.net/cloud-init/+bug/1976526

Comment 3 Major Hayden 🤠 2023-03-28 22:25:37 UTC

PR made to patch cloud-init: https://src.fedoraproject.org/rpms/cloud-init/pull-request/29

Comment 4 Fedora Update System 2023-05-17 13:34:30 UTC

FEDORA-2023-8d4d62dfd2 has been submitted as an update to Fedora 39. https://bodhi.fedoraproject.org/updates/FEDORA-2023-8d4d62dfd2

Comment 5 Fedora Update System 2023-05-17 13:36:11 UTC

FEDORA-2023-8d4d62dfd2 has been pushed to the Fedora 39 stable repository.
If problem still persists, please make note of it in this bug report.