Container networking on Kubernetes broken after Server 2022 July 2024 / KB5040437 (OS Build 20348.2582) update

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#516 opened on Jul 17, 2024 74 comments 3 reactions 0 assignees View on GitHub

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Assessment

Difficulty: 4/5
Estimated time: 3-5 days
Newbie friendliness: 42/100

Issue type: Bug
Clarity: Mostly clear
Activity status: Active
Tech stack: kubernetes
Domain: infrastructure, networking, operating-systems

Research direction

Reproduce on a Windows Server 2022 worker using the documented Calico VXLAN setup, containerd 1.6.31, and the July cumulative update KB5040437. Start by comparing pod networking before and after the update, including ping or curl from a container and pod-to-pod or Service access. Done means pod external, pod-to-pod, and Service connectivity work without uninstalling the update.

Written by the indexing model from the issue text.

Description

🔖 ADO bug Networking Windows on Kubernetes

Describe the bug
Pod networking breaks after installing the July CU on Windows Server 2022. For eg, ping microsoft.com from within the container returns General failure. The pod is not reachable from the other pods or through a Service.

Uninstalling KB5040437 fixes the issue.

To Reproduce

Setup a Windows worker with Calico VXLAN CNI provider (https://docs.tigera.io/calico/latest/getting-started/kubernetes/windows-calico/manual-install/standard)
Install the July cummulative update on the Server 2022 worker
Exec into a running container on the worker
ping or curl any address

Expected behavior

The pod should be able to reach to external network as well should be reachable from other pods

Configuration:

Edition: Windows Server
Base Image being used: Windows Server Core
Container engine: containerd
Container Engine version: 1.6.31

/label Windows on Kubernetes

Dominant language: PowerShell
Stars: 551
Forks: 76
PR merge metrics: No merged PRs in 30d

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