> ## Documentation Index
> Fetch the complete documentation index at: https://docs.nanovm.dev.lithosai.cloud/llms.txt
> Use this file to discover all available pages before exploring further.

# Use your own image

> Any OCI image, private registries, pre-built templates, and the full-VM runtime.

```python theme={null}
sb = nv.sandboxes.create(image="ghcr.io/org/app:tag", cpus=4, memory_mb=4096)
nv.registries.put(host="ghcr.io", username="me", password="<token>")   # private pulls, stored once
t = nv.templates.build("python:3.12-slim", cpus=2, memory_mb=1024)     # pre-build to skip first-use wait
sb = nv.sandboxes.create(image="docker:28-dind", runtime="vm")         # the image IS the machine (experimental)
```

The **first** create of an image at a shape builds a template once (seconds for
small images, minutes for huge ones); the SDK waits by default
(`wait_for_template=False` raises `TemplateBuildingError` to poll yourself).
After that it is fast for everyone (public images) or your org (private ones).

## Sharp edges

Templates are per `(image, cpus, memory_mb, runtime)`. In the
`vm` runtime don't start a second dockerd on dind images — the image's own
daemon already holds the socket. Omitting the image gives the **default
sandbox** (Python 3.12, Node 22, common data-science stack, 2 vCPU/1 GiB,
\~50–100 ms from a warm pool); it sets `PIP_NO_CACHE_DIR=1`, so repeated
installs in one sandbox want `PIP_NO_CACHE_DIR=0 pip install …`.