Dev Boxes¶

m-gpux dev gives you a GPU (or CPU) machine on Modal that you use like any remote server: SSH into it, open it in VS Code, pause it overnight, and pick up exactly where you left off.

cd my-project
m-gpux dev            # same as: m-gpux dev up

Under the hood each box is a Modal Sandbox running sshd, with your folder copied into /workspace.

Quick start¶

m-gpux dev up                 # pick account + GPU, uploads this folder
m-gpux dev code               # open /workspace in VS Code (Remote-SSH)
ssh m-gpux-my-project         # or plain ssh — the host alias is written for you
m-gpux dev pause              # snapshot everything, stop billing compute
m-gpux dev resume             # continue later — installs and files are still there
m-gpux dev down               # delete the box

Commands¶

Command	What it does
`dev up`	Create a box for the current folder and connect
`dev list`	All boxes with state, account, cost/hour and auto-stop time
`dev ssh [name]`	SSH session
`dev code [name]`	Open the box in VS Code via Remote-SSH
`dev shell [name]`	Terminal via `modal shell` (via SSH on Windows, where `modal shell` isn't supported)
`dev sync push` / `pull`	Copy files local → box, or box → local
`dev pause [name]`	Snapshot the full filesystem, then stop the box
`dev resume [name]`	Start again from the last snapshot
`dev down [name]`	Stop the box and forget it
`dev web`	The classic browser terminal (ttyd) dev container

[name] defaults to the box for the current folder, or the only box you have.

`dev up` options¶

Option	Description	Default
`--name`, `-n`	Box name	current folder name
`--image`	Start from a published image (`m-gpux image build`)	asked if you have any
`--hours`	Auto-stop after N hours (max 24)	`12`
`--ssh/--no-ssh`	Run `sshd` for ssh / VS Code	on
`--lock-ip`	Only accept connections from your current public IP	off
`--upload/--no-upload`	Copy this folder into `/workspace`	on

Pause and resume¶

dev pause takes a snapshot of the whole filesystem: pip installed packages, apt packages, datasets you downloaded, edited code. Then it stops the box. While paused, no compute is billed. dev resume boots a new box from that snapshot in a few seconds, with a fresh SSH address that is written to ~/.ssh/config for you.

Snapshots are kept for 30 days by default (--keep-days).

Auto-stop

A box stops on its own after --hours (Modal Sandboxes live at most 24 hours). Anything not paused or synced by then is lost, so run m-gpux dev pause at the end of a session. dev list shows each box's auto-stop time.

File sync¶

m-gpux dev sync push          # only files changed since the last push
m-gpux dev sync push --all    # everything
m-gpux dev sync pull          # box → the folder the box was created from (asks first)
m-gpux dev sync pull --to ./from-box

Sync skips the exclude patterns you chose at dev up (.venv, node_modules, .git, … by default). With VS Code Remote-SSH you edit files on the box directly, so you mainly need pull for results and checkpoints.

SSH details¶

m-gpux uses its own key, ~/.m-gpux/ssh/id_ed25519, created on first use. Your own keys are never touched.
Each box gets a Host m-gpux-<name> block in ~/.ssh/config, between # >>> m-gpux dev markers; dev down removes it.
Password login is disabled; only the m-gpux key is accepted.
--lock-ip restricts the box's inbound connections to your current public IP.

Cost¶

Sandbox CPU and memory cost about 3× Function rates (m-gpux billing rates shows both); GPU prices are the same. The dev up picker shows the estimated $/hour for each choice, and dev list shows it for running boxes.

Classic mode¶

The previous browser-terminal container (ttyd + Modal Volume + msync) is still available:

m-gpux dev web
m-gpux dev --preset rl-a100    # presets run in classic mode