# Release 0.76

:material-calendar: 2026-06-03 · :material-list-status: [Full Changelog](https://github.com/srl-labs/containerlab/releases)

## NVIDIA Cumulus VX VM

The [`nvidia_cumulusvx`](../manual/kinds/nvidia_cumulusvx.md) kind brings Cumulus VX back through a VM-based workflow {==and sunsets the container-based `cvx` kind==}. Use a containerlab-compatible image built from the original qcow2 image with [vrnetlab](../manual/vrnetlab.md) or boxen-v2, and model dataplane interfaces as `swpN` ports that match the Cumulus configuration.

> While NVIDIA does not distribute the Cumulus VX image anymore through their developer's portal, the sneaky petes always find a way to get their hands on a qcow2.

Thanks @BurlyLuo #3209

## Remote startup-config and license files

Node artifacts do not have to live on the lab host anymore. The [`startup-config`](../manual/nodes.md#startup-config) and [`license`](../manual/nodes.md#license) fields can now use local files, embedded blobs, or remote URLs. Remote downloads support `https`, `http`, [S3](../manual/s3-usage-example.md), `ftp`, `sftp`, and `scp`.

```yaml
topology:
  nodes:
    srl1:
      startup-config: sftp://user@example.com/configs/srl1.partial.cfg
      license: https://licenses.example.com/srl1/license.key
```

For `sftp` and `scp`, password authentication can be provided in the URL, key-based authentication uses `CLAB_SSH_KEY` and `CLAB_SSH_KEY_PASSPHRASE`, and `SSH_AUTH_SOCK` is used when an SSH agent is available.

Thanks @steiler @FloSch62 #1414

## Containerlab GUI documentation

The GUI docs have been rebuilt around the shared TopoViewer workflow, with dedicated pages for the [VS Code extension](../manual/gui/vsc-extension.md), [Desktop app](../manual/gui/desktop.md), [Web app](../manual/gui/web.md), and browser sandbox.

The new [Containerlab GUI](../manual/gui/index.md) section explains how the Explorer, topology editor, layouts, annotations, packet capture, link impairments, image management, and Grafana bundle export fit together. The [API server](../manual/api-server.md) docs were added alongside it for Desktop and Web deployments.

Thanks @FloSch62 #3206

## Management network controls

Labs that intentionally run all nodes with [`network-mode: none`](../manual/nodes.md#network-mode) can set `mgmt.skip-when-unused: true` to avoid creating an unused management network and empty `/etc/hosts` marker block.

The management-network docs also cover a local-only setup for labs that should keep host-to-container and container-to-container communication while preventing external network access through the management bridge.

Thanks @torbbang @mlaga97 #3191 #3188

## Miscellaneous

- Concurrent deployments on the same host are more reliable thanks to safer `/etc/hosts` lab block handling and Docker network checks. Thanks @torbbang #3190
- Docker container start now retries the transient IPv6 gateway `file exists` failure. Thanks @micyen #3185
- Topology schema validation now requires link `endpoints` and includes the top-level `debug` field. Thanks @alexandrehassan #3199
- Added missing SR Linux IXR models and SR-SIM SAR chassis types to the schema. Thanks @ripnet @sacckth #3196 #3184
- SR Linux and SONiC lab example docs were refreshed with current version information and configuration. Thanks @fatred #3183
- DOT graph output now quotes graph names correctly. Thanks @fabriciojm #3202
- Interface altname setup now warns and continues on kernels that do not support altnames. #3205
- Lifecycle handling for links and SR-SIM nodes was simplified and covered with additional SR-SIM lifecycle tests. Thanks @kaelemc #3195
- Containerlab now builds with Go 1.25. #3193

## Patches

### 0.76.1

- Fancier container image pull rendering with a charm-powered progress UI. #3229
- Interactive topology picker when multiple `*.clab.y[a]ml` files are detected and no `-t` is passed (falls back to the previous error on non-TTY). #3230
- Kernel module checks now also detect modules built into the kernel via `modules.builtin`. #3218
- Fixed Nokia SR-SIM default card/MDA config for integrated (pizza-box) models. #3222
- Updated SR Linux banner links to point at the release-notes navigator and version-matched YANG browser. #3231
- Fixed Discord button rendering on the community page. #3225
- Bumped `github.com/containers/podman/v5` to 5.8.2. #3178
- Docs tooling cleanup: removed the mkdocs insiders image, made the docs test less flaky, and bumped `codecov-action` to v7. #3214 #3223 #3219
- Fixed magic variable expansion in extras field. #3227
