🐳 Docker (Local)

The solver runs inside a Docker container on the same machine as Blender, managed by the local Docker daemon. For a remote container reached over SSH, see Docker over SSH.

Block diagram showing the Blender add-on, the Docker daemon, and the container running server.py all inside a single Blender workstation box. Lifecycle commands travel add-on -> docker-py -> daemon -> exec -> container; server traffic goes add-on -> socket to localhost:port -> container.

Where each piece lives, and how the add-on reaches it, in local Docker mode. Blue solid arrows carry lifecycle commands (container start/stop, exec). Purple dashed arrows carry the TCP connection to server.py. The container must publish the server port – that is what lets the socket reach server.py. For the remote variant where the daemon and container live on a different host, see Docker over SSH.

When to Use It

  • The solver depends on CUDA/driver versions you do not want to install on the host.

  • You want each project isolated on the workstation.

Setup

  1. Set Server Type to Docker.

  2. Fill Container with the Docker container name (default ppf-dev). The container must already exist on the daemon; the add-on will start it if it is stopped, but it will not create one.

  3. Fill Container Path with the working directory inside the container (default /root/ppf-contact-solver). This is the directory containing server.py, not a path on the Blender host.

  4. Set Docker Port to the TCP port server.py listens on inside the container (default 9090).

  5. Click Connect. If the container exists but is stopped, the add-on starts it for you. A missing container is reported as an error.

Backend Communicator panel in Docker mode

Backend Communicator with Server Type set to Docker. Container, Container Path, and Docker Port replace the SSH fields. The Install Docker-Py banner appears when the vendored module is missing. Connect is highlighted.

Fields

Field

Description

Container

Docker container name (e.g. ppf-dev). Must already exist on the daemon.

Container Path

Working directory inside the container that holds server.py (e.g. /root/ppf-contact-solver). Not a host path.

Docker Port

TCP port inside the container where server.py listens (default 9090). Must be published with -p when the container was created.

Installing docker-py

The Docker backend requires the docker Python package (sometimes called docker-py). When it is missing the main panel shows an Install Docker button that installs the package into the add-on’s private library on a background thread.

Troubleshooting

  • Container 'X' does not exist. - the name is wrong or the container was removed. Run docker ps -a to see what is actually there.

  • Error starting container 'X' - the daemon returned a non-zero exit or the user lacks docker group membership.

  • Server startup timed out. - the container started but server.py did not become ready within 16 seconds. Check server.log inside the directory set in Container Path; the panel prints the last 20 lines automatically.

  • docker-py not found - click Install Docker on the main panel and wait for the background installer to finish.

Under the hood

Transport

The local backend talks to the Docker daemon through the standard docker Python client and looks up the container by name. A stopped container is started automatically; a missing container aborts connect with Container 'X' does not exist.

Server startup path

Local Docker uses the same Unix server-launch path as the SSH and Local backends (see Connections - Under the hood): a small script inside the container launches server.py on the configured port and the UI waits up to 16 s for readiness. The local mode does not perform the explicit docker port published-port check that Docker over SSH does.