Description
Starting today, I am seeing failures to connect to vault.centos.org during docker build with the error: "Cannot assign requested address"

Area for Triage:

Servers

Question, Bug, or Feature?:

Bug

Virtual environments affected

• Ubuntu 16.04
• Ubuntu 18.04
• Ubuntu 20.04
• macOS 10.15
• macOS 11.0
• Windows Server 2016 R2
• Windows Server 2019

Expected behavior
docker build Completes successfully and can access the internet to update / install fresh packages.

Actual behavior
During the yum -y update step of docker build, the command fails with the error message:

http://vault.centos.org/6.10/os/x86_64/repodata/repomd.xml: [Errno 14] PYCURL ERROR 7 - "Failed to connect to 2600:1f13:2e7:2901:d2b0:c3b2:9347:934c: Cannot assign requested address"

All the information I could find on that error message indicates that it is a networking problem. I'm able to access the above URL directly, so it doesn't appear to be an issue with the source. Additionally, this exact setup worked consistently before today, and no changes were made (other than swapping the environment to test if that would have an impact (it didn't).

Repro steps
This is happening on a CentOS 6 Docker image during the docker build stage. The repo is: https://github.com/volta-cli/volta and you can see the failing jobs here:

• https://github.com/volta-cli/volta/actions/runs/422143760
• https://github.com/volta-cli/volta/actions/runs/422199976