Is there a DNS AAAA record for 2620:52:0:2e39::20 from which to obtain a name? Is there a DHCPv6 provided hostname?

(In reply to Antoni Segura Puimedon from comment #1)
> Is there a DNS AAAA record for 2620:52:0:2e39::20 from which to obtain a
> name? Is there a DHCPv6 provided hostname?

Yes, there's a PTR record:

dig -x 2620:52:0:2e39::20  +short
openshift-master-0.ocp-edge1.lab.eng.tlv2.redhat.com.

DHCPv6 also provides the hostname, pasting below the dnsmasq config:

cat /etc/dnsmasq.d/baremetal.conf 

strict-order
local=/ocp-edge1.lab.eng.tlv2.redhat.com/
domain=ocp-edge1.lab.eng.tlv2.redhat.com
expand-hosts
pid-file=/var/run/dnsmasq.pid
except-interface=lo
bind-dynamic
interface=baremetal
dhcp-option=option6:dns-server,[2620:52:0:aa0::dead:beef]
dhcp-range=2620:52:0:2e39::d1,2620:52:0:2e39::f4,64
dhcp-lease-max=81
dhcp-hostsfile=/var/lib/dnsmasq/baremetal.hostsfile
log-dhcp

cat /var/lib/dnsmasq/baremetal.hostsfile
id:00:03:00:01:48:df:37:c7:75:d8,openshift-master-0.ocp-edge1.lab.eng.tlv2.redhat.com,[2620:52:0:2e39::20]
id:00:03:00:01:48:df:37:c7:76:48,openshift-master-1.ocp-edge1.lab.eng.tlv2.redhat.com,[2620:52:0:2e39::21]
id:00:03:00:01:48:df:37:c7:76:18,openshift-master-2.ocp-edge1.lab.eng.tlv2.redhat.com,[2620:52:0:2e39::22]
id:00:03:00:01:48:df:37:c6:39:f8,openshift-worker-0.ocp-edge1.lab.eng.tlv2.redhat.com,[2620:52:0:2e39::23]
id:00:03:00:01:48:df:37:c7:76:b8,openshift-worker-1.ocp-edge1.lab.eng.tlv2.redhat.com,[2620:52:0:2e39::24]
id:00:03:00:01:BC:97:E1:69:DA:81,openshift-worker-2.ocp-edge1.lab.eng.tlv2.redhat.com,[2620:52:0:2e39::25]
id:00:03:00:01:BC:97:E1:29:9C:81,openshift-worker-3.ocp-edge1.lab.eng.tlv2.redhat.com,[2620:52:0:2e39::26]

RAs providing SLAAC address were originating from radvd:

interface baremetal
{
AdvManagedFlag on;
AdvOtherConfigFlag on;
AdvSendAdvert on;
MinRtrAdvInterval 30;
MaxRtrAdvInterval 100;
AdvDefaultLifetime 100;
prefix 2620:52:0:2e39::/64
{
AdvOnLink on;
AdvAutonomous on;
AdvRouterAddr off;
};
route ::/0 {
AdvRoutePreference medium;
RemoveRoute off;
};
};

I think the SLAAC aspect is a red herring. I am able to deploy with both DHCPv6 and SLAAC addresses locally.

Looking through the logs I see a couple of issues. First, the hostname is not in the dhcp6 options reported by NM. I thought that was fixed for 4.6, but I could be mistaken. Maybe it wasn't fixed yet in 4.6.3? It should definitely be fixed in 4.7.

Second, the resolv-prepender script is failing. Possibly related to https://bugzilla.redhat.com/show_bug.cgi?id=1905233 since the subnets overlap? I think we'd need to see the output from the resolv-prepender in order to figure out what's going on there.

I should note that I've done several deployments with SLAAC addresses in my dev environment and haven't been able to reproduce this problem. Even using overlapping subnets has not been an issue. Tomorrow I might try deploying 4.6.3 specifically just to see if this is something that was accidentally fixed since then.

I was able to reproduce this bug in 4.6.3 but not in 4.6.9, so I believe this was fixed since the bug was opened.

Verified on OCP 4.7.0-fc.1

[core@master-0-0 ~]$ hostname
master-0-0.ocp-edge-cluster-0.qe.lab.redhat.com

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: OpenShift Container Platform 4.7.0 security, bug fix, and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2020:5633