sentry-cli's glibc fails dns resolution in docker containers when IPv6 returns NXDOMAIN (even if ipv4 succeeds) #3203
Description
CLI Version
2.24.1, 3.3.1 (anything above 2.21.1 is broken but 2.21.1 works)
Operating System and Architecture
- macOS (arm64)
- macOS (x86_64)
- Linux (i686)
- Linux (x86_64)
- Linux (armv7)
- Linux (aarch64)
- Windows (i686)
- Windows (x86_64)
Operating System Version
Ubuntu 22.04
Link to reproduction repository
No response
CLI Command
sentry-cli releases new
Exact Reproduction Steps
- Run any EC2 instance in AWS (this is necessary)
- Start any docker image (e.g., alpine/ubuntu)
- this step is also necessary; docker returns NXDOMAIN for missing record types
- DNS resolution for sentry.io returns the right address with IPv4 but returns NXDOMAIN for IPv6
$ docker run -it alpine sh
...
/ # host sentry.io
sentry.io has address 35.186.247.156
sentry.io has address 35.186.247.156
Host sentry.io not found: 3(NXDOMAIN)
Host sentry.io not found: 3(NXDOMAIN)
Try to create a sentry release, params don't matter -> dns resolution fails
sentry-cli ... releases new ...
This works if I run the docker container with --dns 8.8.8.8 (e.g., because the upstream resolver returns differently from AWS's)
Expected Results
Sentry-cli to create a release
Actual Results
CLI errors with a DNS resolution against sentry.io
error: API request failed
caused by: [6] Couldn't resolve host name (Could not resolve host: sentry.io)
Logs
DEBUG 2026-03-10 16:57:31.637555109 +00:00 sentry-cli version: 2.24.1, platform: "linux", architecture: "x86_64"
...
DEBUG 2026-03-10 16:57:31.639211567 +00:00 request POST https://sentry.io/api/0/projects/<redacted>
...
DEBUG 2026-03-10 16:57:31.639345965 +00:00 retry number 0, max retries: 0
error: API request failed
caused by: [6] Couldn't resolve host name (Could not resolve host: sentry.io)