PXEboot interface is left with IPv6 autoconf turned on after initial install, before ansible playbook execution

[Andre Kantek]

Brief Description

During tests of B&R it was observed that the system was keeping IPv6 autoconf turned on in controller-0 after the PXEboot installation

This happened because the kickstart script is setting the loopback instead of the interface

root@yow-cgcs-wildcat-71:/var/home/sysadmin# cat /etc/network/interfaces.d/ifcfg-eno1
auto eno1
iface eno1 inet dhcp
post-up echo 0 > /proc/sys/net/ipv6/conf/lo/autoconf; echo 0 > /proc/sys/net/ipv6/conf/lo/accept_ra; echo 0 > /proc/sys/net/ipv6/conf/lo/accept_redirects

Severity

<Minor: System/Feature is usable with minor issue>

Steps to Reproduce

Install the system without this correction and observe if an IPv6 address is not added to the system. E.g.

root@yow-cgcs-wildcat-71:/var/home/sysadmin# ipb a
lo UNKNOWN 127.0.0.1/8 ::1/128
eno1 UP 128.224.151.215/23 2620:10a:a001:a103:a6bf:1ff:fe00:186/64 2620:10a:a001:a103::1215/64

Observe that the autoconfigured IPv6 (2620:10a:a001:a103:a6bf:1ff:fe00:186/64) is composed of the interface MAC address, in a similar way to a link-local address.

Expected Behavior

There should not be autoconfigured addresses in the PXE boot after installation

Actual Behavior

There are autoconfigured addresses in the PXE boot after installation

Reproducibility

Reproducible, if the switch connected to the pxe interface is replying the autoconf data

System Configuration

AIO-DX or AIO-SX

Load info (eg: 2022-03-10_20-00-07)

Latest StarlingX

Test Activity

Regression Testing

Workaround

1) Remove the offending IPv6 address and
2) set the desired interface with autoconf OFF
echo 0 > /proc/sys/net/ipv6/conf/${ifname}/autoconf; echo 0 > /proc/sys/net/ipv6/conf/${ifname}/accept_ra; echo 0 > /proc/sys/net/ipv6/conf/${ifname}/accept_redirects
3) proceed with the ansible playbook restore configuration

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/starlingx/metal/+/900937

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/starlingx/metal/+/900937
Committed: https://opendev.org/starlingx/metal/commit/97052df958d845108349f7bc9d40833bc3efe446
Submitter: "Zuul (22348)"
Branch: master

commit 97052df958d845108349f7bc9d40833bc3efe446
Author: Andre Kantek <email address hidden>
Date: Tue Nov 14 15:45:14 2023 -0300

    After executing PXE boot install, turn off IPv6 autoconf

    It was detected that the PXE boot the IPv6 autoconf is turned on
    due to an error in the network config file for the PXE interface.
    Instead of applying the config to the interface it is configuring
    the loopback.

    By leaving autoconf turned on the interface it can receive unwanted
    address configuration that can create errors during the ansible
    playbook execution that will follow.

    Closes-Bug: 2043509

    Change-Id: I48584dc6b92fca02205c4774c4624410b6a29ba8
    Signed-off-by: Andre Kantek <email address hidden>