Comment 0 for bug 2043509

Brief Description

During tests of B&R done in wildcat-71-75 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
This can add an extra IPv6 address in the interface that is contributing to the bug
https://jira.wrs.com/browse/CGTS-54117 (although it is not the main cause of that bug)

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