Dev Env
Keeps a persistent smolvm machine with its dependencies already installed and re-enters...
Install
npx skills add smol-machines/smolvm --skill dev-env -g -a claude-code -y- Repository
- smol-machines/smolvm6.9k
- Category
- DevOps
- Updated
- 3d ago
- License
- Apache-2.0
- Context cost
- Mediumabout 3,000 tokens
- Runs scripts
- Yes, review before use
What it does
Keeps a persistent smolvm machine with its dependencies already installed and re-enters it cheaply across sessions. Use when a project needs an isolated development environment that survives stop and start; when deciding what belongs in a Smolfile's init versus what has to run on every boot; when a package installed in a machine has vanished after a restart; or when exec answers "the container smolvm-<hash> is not running". Do not use it for untrusted code, which needs a machine that leaves nothing behind (see the throwaway-machine packet), or for running a Docker daemon inside the machine (see docker-in-machine).
A persistent dev machine
Verified on smolvm v1.29.0 on macOS arm64, 2026-10-15, and on v1.18.2 on Linux aarch64, 2026-09-24; the Linux runs used
the Smolfile with memory = 1024, for the host reason in "Platform arms". Done means a second start is fast, skips provisioning, and the packages installed in
the first session are still there.
The Linux runs used the scripts of their date; this version's preflight and cleanup scripts ran
on Linux aarch64 on v1.22.2 on 2026-10-03.
The whole use case turns on one fact: init runs once, not on every start, as
smolfile.md says, and as the docs site (smolmachines.com/docs) says under "When
init runs". smolvm machine create --help reads "Run command on every VM start" at v1.22.2, and
"Run command once, on the machine's first start" from v1.23.7; provisioning that relies on the old
line is missing on the second boot.
Procedure
1. Preflight.
scripts/preflight.sh
Read-only. restart_after_stop=verified on macOS and Linux. The script covers macOS and Linux
only; elsewhere it prints unknown and a note pointing at references/windows.md, where a stopped
machine starts again on v1.14.6 and v1.22.2.
2. Declare the machine. assets/dev.smolfile is a working starting point, and the one
verify-persistence.sh is written against: it asserts the app user and the /app workdir that
file sets. examples/python-app/python.smolfile and examples/node-app/node.smolfile in the
repository are plainer examples without them.
image = "python:3.12-alpine"
net = true
cpus = 2
memory = 2048
volumes = ["./src:/app"]
init = [
"sh -c \"id -un > /init-ran-as.txt\"",
"sh -c \"date +%s >> /init-count.txt\"",
"adduser -D app",
]
user = "app"
workdir = "/app"
3. Create and bring it up. Run this from the project directory: the Smolfile mounts ./src,
which is relative to the working directory, and the script creates ./src there if it is missing.
