Bug 2123478
| Summary: | dns-nameservers settings appears to be broken in train 16.2.3 | ||
|---|---|---|---|
| Product: | Red Hat OpenStack | Reporter: | David Hill <dhill> |
| Component: | openstack-neutron | Assignee: | Elvira <egarciar> |
| Status: | CLOSED CURRENTRELEASE | QA Contact: | Eran Kuris <ekuris> |
| Severity: | medium | Docs Contact: | |
| Priority: | high | ||
| Version: | 16.2 (Train) | CC: | chrisw, egarciar, ltamagno, ralonsoh, scohen, svigan, tdoucet, twilson |
| Target Milestone: | --- | Keywords: | Triaged |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | All | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | If docs needed, set a value | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2023-07-28 16:14:02 UTC | Type: | Bug |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
I just reproduced this with a RHEL 8.4 : [cloud-user@test-dave ~]$ cat /etc/resolv.conf ; Created by cloud-init on instance boot automatically, do not edit. ; nameserver 0.0.0.0 [root@overcloud-vcontroller-0 ~]# podman exec -i ovn-dbs-bundle-podman-0 ovn-nbctl list DHCP
_uuid : b172bfaa-8683-4192-b5ff-68460bb2121c
cidr : "10.0.0.0/24"
external_ids : {"neutron:revision_number"="1", subnet_id="197b33d2-53cf-41df-b8f2-11535e08cdc4"}
options : {classless_static_route="{169.254.169.254/32,10.0.0.100, 0.0.0.0/0,10.0.0.1}", dns_server="{0.0.0.0}", lease_time="43200", mtu="1500", router="10.0.0.1", server_id="10.0.0.1", server_mac="fa:16:3e:01:35:0d"}
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Problems : 1/ When a VM is created in a subnet with a default DNS value defined as 0.0.0.0 -> The VM file /etc/resolv.conf is not empty (as expected) but have the value 0.0.0.0 2/ When a VM is created in a subnet where the option --dns-nameserver is used to have no DNS defined at the subnet level -> The VM file /etc/resolv.conf is not empty (as expected) and will have the value of the default DNS of the UnderCloud -> More over : if a default value should has been taken it should be value of : - dns_nameservers pram in the ~/undercloud.conf file OR - DnsServers param in the ~/templates/environments/network-environment-overrides.yaml ### After the UpGrade from 16.2.1 to 16.2.3 we have done the following tests : Intro : We have used two diffèrent images to to create the tests VM : -> VM with CIRROS Image -> VM with Almalinux image Spoil : The tests show that : -> The result can depend on the VM image -> The behaviour of the VMs can be very complecated depending on the test scenario Tests détails : 1a/ Create the VM in a subnet with no DNS using the --no-dns-nameservers option -> VM Cirros : /etc/resolv.conf value at 10.10.10.10 (undercloud default DNS) -> VM Almalinux : /etc/resolv.conf value at 10.10.10.10 (undercloud default DNS) 1b/ Define the DNS subnet value as 0.0.0.0 AND then reboot the VM in the subnet with the DNS value at 0.0.0.0 -> VM Cirros : /etc/resolv.conf value at 0.0.0.0 -> VM Almalinux : /etc/resolv.conf value at empty !!! 1c/ Destroy the VM AND then deploy it again in the subnet with DNS value at 0.0.0.0 -> VM Cirros : /etc/resolv.conf value at 0.0.0.0 -> VM Almalinux : /etc/resolv.conf value at 0.0.0.0 1d/ Reboot the VM in the subnet with DNS value at 0.0.0.0 -> VM Cirros : /etc/resolv.conf value at 0.0.0.0 -> VM Almalinux : /etc/resolv.conf value at 0.0.0.0 1e/ Define the DNS subnet value as empty with the --no-dns-nameservers option AND then reboot the VM -> VM Cirros : /etc/resolv.conf value at 10.10.10.10 -> VM Almalinux : /etc/resolv.conf value at 0.0.0.0 1f/ Define the DNS subnet value at 0.0.0.0 AND then reboot the VM -> VM Cirros : /etc/resolv.conf value at 0.0.0.0 -> VM Almalinux : /etc/resolv.conf value at 0.0.0.0