Bug 2160942
| Summary: | Failed at DNS verification when applying a state with many veth to be activated | ||||||||
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| Product: | Red Hat Enterprise Linux 9 | Reporter: | Mingyu Shi <mshi> | ||||||
| Component: | nmstate | Assignee: | Gris Ge <fge> | ||||||
| Status: | CLOSED ERRATA | QA Contact: | Mingyu Shi <mshi> | ||||||
| Severity: | high | Docs Contact: | |||||||
| Priority: | medium | ||||||||
| Version: | 9.2 | CC: | ferferna, jiji, jishi, network-qe, sfaye, till | ||||||
| Target Milestone: | rc | Keywords: | Regression, Triaged | ||||||
| Target Release: | --- | ||||||||
| Hardware: | Unspecified | ||||||||
| OS: | Unspecified | ||||||||
| Whiteboard: | |||||||||
| Fixed In Version: | nmstate-2.2.5-1.el9 | Doc Type: | No Doc Update | ||||||
| Doc Text: | Story Points: | --- | |||||||
| Clone Of: | Environment: | ||||||||
| Last Closed: | 2023-05-09 07:31:53 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: | |||||||||
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Description
Mingyu Shi
2023-01-14 15:36:55 UTC
Created attachment 1938075 [details]
nmstate+NMtrace.log
Hello, I was able to reproduce it. We will add this to our backlog and work on it when we have capacity. Thanks for reporting! Patch sent to upstream: https://github.com/nmstate/nmstate/pull/2201 Q: Why is it random failure? A: Previous code is using `HashMap::iter()` to search valid interface to store the DNS. When it place bond before veth, the we see no problem, otherwise problem been triggered. That also explains why you need too many(34) veth to increase the chance of hitting the problem. Q: Root cause? A: The newly created veth2+ is holding IPv6 link local address which make it suitable for storing the IPv6 DNS server. But when the desire state has no IPv6 defined, nmstate forgot to copy IPv6 stack from current before applying DNS settings. Q: What's the fix? A: Just copy IP stack from current if not desired but marked to hold DNS info. Q: Why use veth2+ instead of bond interface which also hold IPv6 info? A: The posted patch changed this behavior, we first try `preferred` DNS interface, then we try `valid` DNS interface. The `perfered` here means desire interface hold desire IP and suit for DNS. Interface holding IPv6 link local address only is not preferred for IPv6 DNS. Q: Any fix for the random problem? A: The posted patch will use insert order of interface in desire state when searching DNS interface. If not found int desire state, we use sorted current interface name for DNS. This eliminate the random problem, so nmstate be consistent on choosing DNS interface. Verified with: nmstate-2.2.5-1.el9.x86_64 nispor-1.2.9-1.el9.x86_64 NetworkManager-1.41.90-1.el9.x86_64 DISTRO=RHEL-9.2.0-20230127.12 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 (nmstate 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/RHBA-2023:2190 |