Use S3 — RustFS in a Slicer VM

RustFS is a high-performance, S3-compatible object storage server written in Rust. Use it when you need a local S3 endpoint for:

Development and CI against S3 APIs without touching AWS
Integration tests for tools that speak S3 (boto3, aws-cli, mc, Terraform, etc.)
Air-gapped or sandboxed object storage
A throwaway S3 target for benchmarks

Upstream: https://rustfs.com — docs: https://docs.rustfs.com

This skill assumes you also have use-slicer — RustFS runs inside a Slicer microVM so it's isolated and disposable.

TL;DR

# 1. Persistent sandbox VM, tagged so you can find it again
VM_NAME=$(slicer vm add sbox --persistent \
  --tag "workflow=rustfs" --tag "app=s3" \
  | awk '/Hostname:/ {print $2; exit}')
slicer vm ready "$VM_NAME"

# 2. Install prereqs + RustFS (non-interactive)
slicer vm exec "$VM_NAME" --uid 1000 -- \
  "sudo apt-get update -qq && sudo apt-get install -y -qq unzip curl"
slicer vm exec "$VM_NAME" --uid 1000 -- \
  "curl -sSL -o /tmp/install_rustfs.sh https://rustfs.com/install_rustfs.sh && \
   printf '1\n9000\n\n\n\n\n\n\n' | sudo bash /tmp/install_rustfs.sh"

# 3. Forward the S3 API to the host (optional — only if you want host access)
slicer vm forward "$VM_NAME" -L 9000:127.0.0.1:9000 &
slicer vm forward "$VM_NAME" -L 9001:127.0.0.1:9001 &  # web console

Service is now listening on port 9000 (S3 API) and 9001 (web console) inside the VM, with default credentials rustfsadmin / rustfsadmin and data at /data/rustfs0.

Why a VM?

RustFS wants to bind privileged directories (/data/rustfs0, /var/logs/rustfs) and install a systemd unit. Running it inside a disposable Slicer VM keeps your host clean, lets you snapshot/reset the storage instantly, and matches production-like deployment.

Always launch with --persistent + descriptive --tags so the VM survives daemon restarts and can be rediscovered:

slicer vm list --json | jq -r '.[] | select(.tags.workflow=="rustfs") | .hostname'

On slicer-mac use the sbox host group explicitly. On Slicer for Linux, list groups first (slicer vm group) or omit the positional to use the default.

Installation details

The official installer is interactive. Feed it default answers with a printf pipe:

printf '1\n9000\n\n\n\n\n\n\n' | sudo bash /tmp/install_rustfs.sh

The 1 picks "Install"; the remaining blank lines accept defaults for port, console port, data dir, access key, secret key, etc.

After install, config lives at /etc/default/rustfs:

RUSTFS_ACCESS_KEY=rustfsadmin
RUSTFS_SECRET_KEY=rustfsadmin
RUSTFS_VOLUMES="/data/rustfs0"
RUSTFS_ADDRESS=":9000"
RUSTFS_CONSOLE_ADDRESS=":9001"
RUSTFS_CONSOLE_ENABLE=true

Change keys before anything touches real data:

slicer vm exec "$VM_NAME" --uid 1000 -- \
  "sudo sed -i 's/=rustfsadmin/=$(openssl rand -hex 16)/' /etc/default/rustfs && \
   sudo systemctl restart rustfs"

Service management:

slicer vm exec "$VM_NAME" --uid 1000 -- "sudo systemctl status rustfs --no-pager"
slicer vm exec "$VM_NAME" --uid 1000 -- "sudo journalctl -u rustfs -n 50 --no-pager"

An unauthenticated GET on / returns HTTP 403 when the server is healthy — that's the AWS-compatible "no anonymous access" response, not a failure.

Talking to it with boto3

Endpoint http://127.0.0.1:9000 (inside the VM, or via port-forward from the host):

import boto3

s3 = boto3.client(
    "s3",
    endpoint_url="http://127.0.0.1:9000",
    aws_access_key_id="rustfsadmin",
    aws_secret_access_key="rustfsadmin",
    region_name="us-east-1",
)

s3.create_bucket(Bucket="demo")
s3.put_object(Bucket="demo", Key="hello.txt", Body=b"hello\n")
print(s3.get_object(Bucket="demo", Key="hello.txt")["Body"].read())

Notes for S3 clients:

Always pass endpoint_url — without it boto3 hits real AWS.
region_name is required by the SigV4 signer, but RustFS ignores the value.
Use path-style addressing for CLI tools (--endpoint-url ... --addressing-style path) — virtual-host style requires DNS for every bucket.
No HTTPS by default. For TLS, terminate in front (nginx/caddy) or configure RustFS's TLS options.

aws-cli

aws --endpoint-url http://127.0.0.1:9000 \
    --no-verify-ssl s3 mb s3://demo
aws --endpoint-url http://127.0.0.1:9000 \
    s3 cp ./file.txt s3://demo/

Credentials via env: AWS_ACCESS_KEY_ID=rustfsadmin AWS_SECRET_ACCESS_KEY=rustfsadmin.

MinIO client (`mc`)

mc alias set rustfs http://127.0.0.1:9000 rustfsadmin rustfsadmin
mc mb rustfs/demo
mc cp ./file.txt rustfs/demo/

Web console

The console at port 9001 is a browser UI for browsing buckets, users, and policies. Forward it:

slicer vm forward "$VM_NAME" -L 9001:127.0.0.1:9001 &
open http://127.0.0.1:9001    # macOS

Testing from inside the VM

Prefer running tests in-VM — zero network hops and no port-forward juggling:

slicer vm exec "$VM_NAME" --uid 1000 -- \
  "pip3 install --quiet --break-system-packages boto3"
slicer vm cp ./rustfs_test.py "$VM_NAME":/tmp/rustfs_test.py --uid 1000
slicer vm exec "$VM_NAME" --uid 1000 -- "python3 /tmp/rustfs_test.py"

Troubleshooting

Symptom	Cause / fix
`curl http://127.0.0.1:9000/` returns 403	Healthy — S3 requires auth; not a failure
Installer hangs on "Please choose an option"	Script is interactive. Pipe `printf '1\n9000\n\n\n\n\n\n\n'` in.
boto3: `InvalidAccessKeyId`	Keys in `/etc/default/rustfs` were changed; restart service after edit
boto3: `Could not connect to endpoint`	Port forward not running, or daemon down (`systemctl status rustfs`)
`CreateBucket` fails with signature error	Virtual-host addressing against `127.0.0.1`; switch to path-style
Data appears lost after VM delete	You deleted the persistent VM. Snapshot via `slicer vm suspend` or export disk first.

Reset / teardown

# Wipe just the data, keep the VM
slicer vm exec "$VM_NAME" --uid 1000 -- \
  "sudo systemctl stop rustfs && sudo rm -rf /data/rustfs0/* && sudo systemctl start rustfs"

# Uninstall RustFS, keep the VM
slicer vm exec "$VM_NAME" --uid 1000 -- "printf '2\n' | sudo bash /tmp/install_rustfs.sh"

# Nuke the whole VM
slicer vm delete "$VM_NAME"

use-s3-rustfs