CapabilitiesSnapshots and forks
Copy a running machine
Make copies of a machine while it keeps running.
Who offers it
Part of Snapshots, forks and templates, which explains why it matters.
Fully: Agent 37, Boat, boxd, Daytona, E2B, Lizard, Morph, Runtime and Tensorlake. With a catch: Blaxel, InstaBox, Sandboxer and Vercel Sandbox. Not at all: Cloudflare Sandbox, Modal and Sprites.
- Agent 37Yes
Note: The copy has the same files, but nothing that was running keeps running.
docs-confirmed “The source keeps running throughout and is not touched.” Source
- BoatYes
Note: The copy has the same files, but nothing that was running keeps running.
docs-confirmed “Keeps running. boat does not change it” Source
The source pauses for a fraction of a second while the copy is taken.
docs-confirmed “The copy includes the disk, **the memory, and every running process**” Source
- DaytonaYes
The fork is independent, but the parent cannot be deleted while forks exist.
docs-confirmed “Forking creates a duplicate of a Linux VM sandbox’s filesystem and memory state in a new sandbox.” Source
Note: The source pauses while it is copied and its open connections drop.
docs-confirmed “During the fork, the original sandbox is paused and resumed.” Source
Note: A fork is refused when the source has a volume attached.
docs-confirmed “`fork` copies a running sandbox, memory and processes included; it returns 409 when a volume is attached.” Source
- MorphYes
A branch snapshots the source and launches the copies.
docs-confirmed “Branching an instance creates multiple clone instances based on the current state of the original instance.” Source
- RuntimeYes
Note: The source is frozen while the copy is captured, so it pauses for a moment.
docs-confirmed “A fork is a copy of a sandbox as it is now. It has the same files, memory and running processes.” Source
- TensorlakeYes
docs-confirmed “Cloning a sandbox is done with `tl sbx copy` or `sandbox.copy()` in either SDK.” Source
- BlaxelWith a catch
The catch: You can copy a running machine, but the feature is in private preview.
docs-confirmed “Calling `fork()` automatically snapshots the source sandbox’s current state and forks from it.” Source
The catch: A copy is made in a few seconds and carries the files but not the running programs.
docs-confirmed “copies a running or stopped machine into one new machine” Source
- SandboxerWith a catch
The catch: A fork copies the files and boots fresh; the running programs are not copied.
docs-confirmed “A fork copies the disk only, never memory or running processes” Source
- Vercel SandboxWith a catch
The catch: A fork starts from a snapshot of the current state, and taking one stops the session it copies.
docs-confirmed “You can also snapshot a running sandbox at any time by calling `snapshot()`, which captures its current filesystem before stopping the session.” Source
There is no way to copy a running instance.
inferred “Starting with a snapshot creates a new instance with the saved files, and the new instance runs its entrypoint. The processes that were running do not continue.” Source
- ModalNo
A fork starts several sandboxes from a saved filesystem; it is not a copy of a running machine.
docs-confirmed “Since Filesystem Snapshots are [Images](/docs/sdk/py/latest/modal.Image), you can create multiple Sandboxes from the same snapshot.” Source
- SpritesNo
A checkpoint restores over the same Sprite; starting a new one from it is not documented.
inferred “It's a save point you create on purpose, a snapshot of the filesystem at one moment that you can return to later.” Source
Related
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