# The runtime

> The image, hardware, filesystem and environment every run starts with.

## Image

`pytorch/pytorch:2.14.0-cuda12.6-cudnn9-runtime`: Python, PyTorch 2.14, CUDA 12.6 and cuDNN 9, on every SKU.

`--image` replaces it with any public image that has `sh`, and `python` for a `.py` entrypoint. Other dependencies are installed by the image or by the command:

```bash
div run -- 'pip install -r requirements.txt && python train.py'
```

The image's Python is Ubuntu's, which marks itself as externally managed, so pip would refuse to install into it. Every run is started with `PIP_BREAK_SYSTEM_PACKAGES=1`, which lets it: the container is thrown away when the run ends, so there is no system to break.

## Hardware

| SKU | GPU | CPU | Memory |
| --- | --- | --- | --- |
| `b300`, `h200`, `h100` | `--gpus` of them | 1 core per GPU | 8 GiB per GPU |
| `cpu` | — | 1 core | 2 GiB |

That is the container a run gets when it does not ask. `--cpu` and `--memory` ask for another, up to 64 cores and 336 GiB, at $0.17 an hour for each core past these and $0.03 for each GiB: see [The container](https://docs.divergentlabs.xyz/compute/cli/run.md#the-container). A run is held to its container: past its memory it is killed, and past its cores it is slowed.

## Filesystem

| Path | What it holds | Kept |
| --- | --- | --- |
| `/workspace` | the shipped code; the command starts here | no |
| `/mnt/<volume>` | every volume the org has | yes |
| `/tmp/divergent/result.json` | the run's [result](https://docs.divergentlabs.xyz/compute/cli/result.md) | as the result |
| `/tmp/divergent/telemetry.jsonl` | the run's [telemetry](https://docs.divergentlabs.xyz/compute/cli/telemetry.md), one JSON object per line | as points |

With `--no-upload`, the command starts in the image's working directory.

Volumes are mounted when the run starts, so `/mnt/<volume>` is a volume only if one by that name exists by then. Any other directory under `/mnt` is the container's own disk, and what is written there goes when the run ends.

A volume the command names is made before the run is queued, the way `div storage put` makes the one it names, and the log says so:

```text
div run -- 'mkdir -p /mnt/mask-models/base && python download.py'
new volume mask-models, for the /mnt/mask-models the command names
```

A path the code builds for itself is not read. Make that volume first, with `div storage put mask-models <path>` or a command that names it. If a run leaves anything in a directory under `/mnt` that is not a volume, the last lines of its log name the directory and how much was lost:

```text
/mnt/mask-models is not a volume, so the 1.1G the run wrote there went with the container. Volumes are mounted when a run starts: make mask-models first with div storage put mask-models <path>, or name /mnt/mask-models in the command.
```

## Environment

Later rows win:

| Source | Variables |
| --- | --- |
| The runtime | `PIP_BREAK_SYSTEM_PACKAGES=1` |
| [Secrets](https://docs.divergentlabs.xyz/compute/cli/secrets.md) | every secret the org has |
| `--env` | each `KEY=value` given |
| The run | `DIVERGENT_RUN_ID`, `DIVERGENT_RUN_NAME`, `DIVERGENT_RESULT_PATH`, `DIVERGENT_TELEMETRY_PATH` |
| An [eval run](https://docs.divergentlabs.xyz/compute/cli/eval.md) | `DIVERGENT_MODEL`, `DIVERGENT_MODEL_VERSION_ID`, `DIVERGENT_MODEL_PATH`, `DIVERGENT_MODEL_DIGEST`, `DIVERGENT_EVALUATION` |

## Lifetime

The command runs under `sh -lc`. A run ends when it exits, is stopped, reaches its `--max-spend`, or has run for 24 hours. Its exit code is `div run`'s.