s3.amazonaws.com is automatically rewritten to s3.dualstack.amazonaws.com causing TLS handshake timeout in private networks

[liuqian1990]

---

Description：

When using milvus-backup v0.5.9, the S3 endpoint specified in the configuration is:

https://xxxxx-data-milvus.s3.amazonaws.com

However, during execution, milvus-backup automatically rewrites this endpoint to:

https://xxxxx-data-milvus.s3.dualstack.amazonaws.com

Notice that the keyword dualstack is inserted automatically.

This behavior forces the backup client to access the S3 public dualstack endpoint, which uses IPv6.
In private network environments (e.g., VPC without IPv6, no internet access, or internal DNS only), this results in a failure:

net/http: TLS handshake timeout

Example log:

create backup storage client: storage: create bucket if not exist
storage: s3 list objects Get "https://xxxxx-data-milvus.s3.dualstack.amazonaws.com/...":
net/http: TLS handshake timeout

---

Expected Behavior

milvus-backup should:

1. Respect the S3 endpoint configured by the user, e.g.:

endpoint: s3.amazonaws.com

2. Not automatically rewrite the endpoint to dualstack unless explicitly enabled.

3. Provide a configuration option such as:

useDualStack: false

---

Actual Behavior

• The endpoint is silently rewritten to s3.dualstack.amazonaws.com
• IPv6-only dualstack endpoint is used
• Backup fails in private networks due to TLS handshake timeout

---

Configuration Example

storage:
  type: s3
  s3:
    endpoint: s3.amazonaws.com
    region: ap-southeast-1
    useSSL: true
    s3ForcePathStyle: true

---

Steps to Reproduce

1. Deploy milvus-backup inside a private subnet (no IPv6 / no public internet)
2. Use an S3 endpoint without dualstack
3. Run:

milvus-backup --config backup.yaml create -d xxx -n test

4. Observe milvus-backup rewriting the endpoint and failing at TLS handshake.

---

Environment

• milvus-backup version: v0.5.9
• Running inside private VPC (IPv4 only)
• S3 Gateway/Interface endpoint enabled
• No access to dualstack / public endpoints

---

Logs

(Include the logs you already pasted)

---

Request

Please fix one of the following:

✔ Option 1: Stop forcing dualstack endpoint

✔ Option 2: Add config option to disable dualstack

✔ Option 3: Fully respect user-supplied endpoint

This issue blocks milvus-backup usage in private-cloud / VPC internal-only environments.

[huanghaoyuanhhy]

Thanks! The config example you shared doesn’t look like the standard milvus-backup format.
Could you confirm it’s the actual config file?

Also, please check whether MINIO_ADDRESS is set — it may override your endpoint.

[Shagga01]

Hi, I am Humphrey O. Founder and Team Leader of Red Waters Group.
Red Waters Group is assembling a high-caliber global team of innovators, builders, and digital strategists.
We’re creating a future-forward ecosystem where AI, cloud engineering, automation, cybersecurity, product innovation, and digital architecture converge. If you’re a skilled professional ready to build revolutionary systems, contribute your expertise, and grow with a team driven by ambition and impact—we want you with us. Join us as we engineer the next generation of digital solutions.
👉 Apply here: https://forms.gle/RgLpGKKn5MZMVbRq9