Notebooks and runtimes

A notebook is an ordinary .ipynb file in your workspace. Open one from the Files page (or create one with New Notebook), and the notebook editor loads with a runtime bar at the top. The bar is where you pick a machine, start it, and stop it. Nothing runs until you do.

The runtime bar

Stopped. The bar shows a summary of the current settings and a Start Runtime button. Click the summary to open Runtime settings; Start is disabled, with a hint, when your account is at its concurrent-runtime limit.

Starting. The bar shows Finding a machine… while the cloud allocates an instance and Setting up machine… while the runtime boots and mounts your workspace. Cancel abandons the launch. Provisioning time is never charged. A launch that takes more than 10 minutes (25 on Lambda Cloud) is abandoned and reported.

Running. The bar shows the connection state, the time left when a duration is set, and three controls:

Connect opens a popover with Web Ports (every port the runtime is listening on, plus a field to type one) and SSH Access (the ssh command and config block for this runtime). See Web apps on runtime ports and SSH.
Restart restarts the kernel in place (shortcut 0 0). The machine, the image, the workspace mount and anything you installed survive.
Stop terminates the machine. If you installed packages outside the image during the session, Stop first asks Save installed packages? with Save as Environment or Stop anyway.

While a runtime is running, every setting is locked except Idle stop.

Runtime settings

Row	What you choose
Environment	The container image the runtime boots from: a template or one of your own. Manage environments… opens the Environments page. See Environments.
Provider	The cloud. The GPU classes on offer differ per cloud, and each class launches in a fixed region of that cloud.
Machine	CPU Only with a vCPU count, or a GPU class, how many GPUs, and, where the family sells more than one shape, the vCPU/RAM/NVMe size.
Pricing	On-Demand, or Spot where the provider sells it. Spot is cheaper and can be reclaimed by the cloud, so keep checkpoints in your workspace.
Duration	A hard stop: 30 minutes, 1, 2, 4, 8, 12 or 24 hours, or Infinite (shown as ∞ in the bar). The picker preselects 30 minutes.
Idle stop	15, 30, 60, 120 or 240 minutes, or Never. The default is 120 minutes. A runtime is idle only when there is no user interaction and no cell is executing.
Cost	The credit burn rate of the configuration, in credits per hour ($1 = 100 credits).

Each machine row carries an availability badge with the time it was last checked. A stale badge may warn you; it never promises capacity.

Menus

File: Save (⌘S), Rename, Notebook info, Share…, Save a copy as Environment (bakes the session's installed packages into a new environment), and Download as .ipynb, .py or .html.
Edit: Cut cell (X), Copy cell (C), Paste cell below (V), Clear all outputs, Find and replace (⌘F).
View: Show terminal (⌃`), Show selections panel (named groups of cells you can re-run together), Show table of contents (⌘⇧O), and collapse or expand all inputs or outputs.
Runtime: Run all cells, Interrupt execution (I I), Restart kernel (0 0), Restart runtime (new VM), Disconnect.

Single-key shortcuts work in command mode, with no cell being edited.

Running cells and saving

Run a cell with Shift+Enter. Output streams into the cell as it is produced.
Closing the tab does not kill a running cell. Come back and the outputs produced while you were away replay into the cell.
Autosave writes the notebook 2 seconds after you stop typing, and at least every 5 seconds while you keep typing; the bar shows Saving… and Saved. Leaving the page saves at once. ⌘S saves on demand.
The kernel runs as an ordinary user in /home/user/workspace, your durable workspace filesystem. Everything else on the machine is discarded when the runtime stops; see Packages in your runtime.

The terminal

Show terminal in the View menu, the terminal button in the bar, or Ctrl+ (⌘ on a Mac) opens a shell at the bottom of the notebook. It runs on the same machine, as the same user, starting in ~/workspace, and it is the quickest way to pip install, inspect a GPU with nvidia-smi, or start a web server to open from Web Ports.

Why a runtime stopped

When a runtime ends for a reason other than your Stop, the bar says which:

Message	Meaning
Stopped after the idle timeout	No interaction and no running cell for the idle period.
Reached the session time limit	The Duration you chose ran out.
Spot capacity was reclaimed by the cloud	A spot machine was taken back. Relaunch, or pick On-Demand.
Out of compute credits	Your balance reached zero. Add credits in Settings.
Stopped: monthly spend cap reached	Your spend cap in Settings was hit.
Stopped because a member was removed from the workspace	The owner removed a member who could reach this runtime.
Stopped because the Pro subscription of the account that launched it ended	The launcher's Pro lapsed.
Connection to the runtime was lost	The runtime's tunnel to the platform dropped and did not recover.
The runtime crashed, The runtime agent went offline	The machine failed. Retry launches a fresh one; Report this problem sends the details to the team.

Two notices can appear while a runtime runs: a reminder that a secret your environment references is not defined in this workspace (with a link to Settings, Secrets), and a warning when the machine's CUDA driver is older than your environment expects.

Viewers

A workspace viewer opens notebooks read-only: cells render with their saved outputs, and Start, the terminal and SSH are disabled with a hint. Viewers can still open a running runtime's web ports.

Quickstart: from sign-in to a first GPU cell.
Environments: building the image a runtime boots from.
Limits: runtime, idle and connection bounds.