Bug 1976858 - [FCOS 34] systemd-resolved adds `search .' to /etc/resolv.conf if no search domains provided
Summary: [FCOS 34] systemd-resolved adds `search .' to /etc/resolv.conf if no search d...
Keywords:
Status: CLOSED DUPLICATE of bug 1874419
Alias: None
Product: Fedora
Classification: Fedora
Component: systemd
Version: 34
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: systemd-maint
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2021-06-28 11:45 UTC by John Fortin
Modified: 2021-06-29 10:52 UTC (History)
12 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2021-06-29 10:52:12 UTC
Type: Bug
Embargoed:


Attachments (Terms of Use)

Description John Fortin 2021-06-28 11:45:15 UTC
Description of problem:

In FCOS 33, if OKD is created with static IPs via kernel arguments the DNS a domain not created resulting in an /etc/resolv.conf without a search entry. This is handled by systemd-resolved

FCOS 33 uses systemd-246.14-1.fc33

If FCOS 34 this behavior changed and now systems with static IPs via kernel args and no DNS domain have a line search . added like this

nameserver 10.99.111.1
nameserver 10.99.111.2
search .
This was introduced with: systemd/systemd#17201

FCOS 34 uses systemd-248.3-1.fc34 which includes the above 'enhancement'

Unfortunately this seems to causes a problem with OKD cluster DNS resolution as cluster domains no longer seem to work. Adding new element results in issues such as

openshift/okd#694

Get "https://image-registry.openshift-image-registry.svc:5000/v2/": dial tcp: lookup image-registry.openshift-image-registry.svc on 10.10.8.132:53: no such host


Version-Release number of selected component (if applicable):
FCOS 34

How reproducible:
100%

Comment 1 Viktar Siarheichyk 2021-06-29 06:33:33 UTC
I encounter such a behavior by simple update of packages. Ready to provide additional information if needed. All resolution in the workstation does not work.

Comment 2 Zbigniew Jędrzejewski-Szmek 2021-06-29 10:52:12 UTC
systemd/systemd#17201 was done to maintain consistency between different lookup mechanism.
Even before that change, image-registry.openshift-image-registry.svc would be resolved properly
using nss-dns but not using nss-resolve. As discussed extensively in the bugs, a global search
domain like this doesn't make sense and is dangerous in the general context of machines with more
than one interface. So the upstream / default downstream behaviour is not going to change.

I think the best we can do is provide a better way to opt-in into this who want it.

*** This bug has been marked as a duplicate of bug 1874419 ***


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