Docker Model Runner fails to start on Ubuntu Linux - Network binding error

[andreaslamprecht2021-netizen]

Description

Docker Model Runner fails to start on Ubuntu Linux - Network binding error
Environment

OS: Ubuntu 25.10 (Questing)
Docker Desktop Version: 4.57.0 (215387)
Docker Engine Version: 29.1.3
Model Runner Image: docker/model-runner:latest (sha256:0b4641277ed9d95f698c832533868cc6d19774bce34a1b9327cb9026cae1fc76)
System: UM890 Pro Mini with 64GB RAM

Issue Description
Docker Model Runner fails to initialize with a network binding error when attempting to start. The container cannot bind to the Docker bridge network IP address 172.17.0.1:12434.
Steps to Reproduce

Install Docker Desktop 4.57.0 on Ubuntu 25.10
Enable Open WebUI extension in Docker Desktop
Attempt to start Docker Model Runner using:

bash docker model status

Or use "Retry Integration" in Docker Desktop Extensions → Service Management

Expected Behavior
Docker Model Runner should start successfully and bind to an accessible network interface, allowing the Open WebUI extension to communicate with it for LLM model management.
Actual Behavior
Model Runner fails to start with the following error:
unable to initialize standalone model runner: unable to initialize standalone model runner container: failed to start container docker-model-runner: Error response from daemon: ports are not available: exposing port TCP 172.17.0.1:12434 -> 127.0.0.1:0: listen tcp4 172.17.0.1:12434: bind: cannot assign requested address
Root Cause Analysis
The IP address 172.17.0.1 exists as the Docker bridge network gateway inside the Docker Desktop VM but is not assigned to any network interface on the host system:
bash$ docker network inspect bridge
[
{
"Name": "bridge",
"IPAM": {
"Config": [
{
"Subnet": "172.17.0.0/16",
"Gateway": "172.17.0.1"
}
]
}
}
]

$ ip addr show | grep 172.17.0.1

No output - IP doesn't exist on host

The Model Runner is trying to bind to 172.17.0.1 on the host system, but this address only exists inside the Docker VM, causing the bind failure.
Docker Desktop Status
Docker Desktop itself is running correctly:
bash$ systemctl --user status docker-desktop
● docker-desktop.service - Docker Desktop
Active: active (running)
Memory: 3.7G (peak: 3.8G allocated: 49GB to VM)
The Open WebUI extension container is running successfully:
bash$ docker ps | grep openwebui
openwebui-extension-service Running 172.17.0.2/16
Workaround
Using standalone Ollama and Open WebUI containers works correctly:
bashdocker run -d --name ollama -p 11434:11434 --memory=50g ollama/ollama
docker run -d --name openwebui -p 3000:8080
-e OLLAMA_BASE_URL=http://host.docker.internal:11434
ghcr.io/open-webui/open-webui:main
This suggests the issue is specific to the Docker Model Runner integration, not with Docker networking in general.
Additional Context

The issue appears to be Linux-specific (Docker Desktop on Ubuntu)
Docker Desktop on Linux uses a VM which may handle networking differently than macOS/Windows versions
The Open WebUI extension loads successfully but cannot connect to Model Runner
Service Management tab shows: "Container running. Docker Model Runner needs attention. Not connected to Docker Model Runner."

Possible Solutions

Change bind address: Allow Model Runner to bind to 0.0.0.0 or 127.0.0.1 instead of the bridge gateway IP
Fix network detection: Properly detect available network interfaces on Linux hosts
Use host.docker.internal: Bind to the special Docker hostname instead of a specific IP
Documentation: Add troubleshooting docs for Linux users encountering this issue

Impact
Users on Linux cannot use the integrated Docker Model Runner feature, forcing them to use manual standalone container setups. This reduces the value proposition of Docker Desktop's LLM integration features on Linux platforms.
Logs
See Docker Desktop logs showing Open WebUI running but no Model Runner initialization:
2026-01-25 08:03:47 - Open WebUI Extension loaded successfully
2026-01-25 08:03:51 - INFO: Started server process [1]

No Model Runner logs present

Full diagnostic output available upon request.

Reproduce

1. Install Docker Desktop 4.57.0 on Ubuntu 25.10
2. Enable Open WebUI extension in Docker Desktop
3. Attempt to start Docker Model Runner using:

bash docker model status

4. Or use "Retry Integration" in Docker Desktop Extensions → Service Management

Expected behavior

No response

docker version

Client: Docker Engine - Community
 Version:           29.1.5
 API version:       1.52
 Go version:        go1.25.6
 Git commit:        0e6fee6
 Built:             Fri Jan 16 12:48:44 2026
 OS/Arch:           linux/amd64
 Context:           desktop-linux

Server: Docker Desktop 4.57.0 (215387)
 Engine:
  Version:          29.1.3
  API version:      1.52 (minimum version 1.44)
  Go version:       go1.25.5
  Git commit:       fbf3ed2
  Built:            Fri Dec 12 14:49:51 2025
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v2.2.1
  GitCommit:        dea7da592f5d1d2b7755e3a161be07f43fad8f75
 runc:
  Version:          1.3.4
  GitCommit:        v1.3.4-0-gd6d73eb8
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0

docker info

Client: Docker Engine - Community
 Version:    29.1.5
 Context:    desktop-linux
 Debug Mode: false
 Plugins:
  ai: Docker AI Agent - Ask Gordon (Docker Inc.)
    Version:  v1.17.1
    Path:     /home/andreasl/.docker/cli-plugins/docker-ai
  buildx: Docker Buildx (Docker Inc.)
    Version:  v0.30.1-desktop.1
    Path:     /home/andreasl/.docker/cli-plugins/docker-buildx
  compose: Docker Compose (Docker Inc.)
    Version:  v5.0.1
    Path:     /home/andreasl/.docker/cli-plugins/docker-compose
  debug: Get a shell into any image or container (Docker Inc.)
    Version:  0.0.47
    Path:     /home/andreasl/.docker/cli-plugins/docker-debug
  desktop: Docker Desktop commands (Docker Inc.)
    Version:  v0.2.0
    Path:     /home/andreasl/.docker/cli-plugins/docker-desktop
  extension: Manages Docker extensions (Docker Inc.)
    Version:  v0.2.31
    Path:     /home/andreasl/.docker/cli-plugins/docker-extension
  init: Creates Docker-related starter files for your project (Docker Inc.)
    Version:  v1.4.0
    Path:     /home/andreasl/.docker/cli-plugins/docker-init
  mcp: Docker MCP Plugin (Docker Inc.)
    Version:  v0.35.0
    Path:     /home/andreasl/.docker/cli-plugins/docker-mcp
  model: Docker Model Runner (Docker Inc.)
    Version:  v1.0.7
    Path:     /usr/libexec/docker/cli-plugins/docker-model
  offload: Docker Offload (Docker Inc.)
    Version:  v0.5.40
    Path:     /home/andreasl/.docker/cli-plugins/docker-offload
  pass: Docker Pass Secrets Manager Plugin (beta) (Docker Inc.)
    Version:  v0.0.22
    Path:     /home/andreasl/.docker/cli-plugins/docker-pass
  sandbox: Docker Sandbox (Docker Inc.)
    Version:  v0.6.0
    Path:     /home/andreasl/.docker/cli-plugins/docker-sandbox
  sbom: View the packaged-based Software Bill Of Materials (SBOM) for an image (Anchore Inc.)
    Version:  0.6.0
    Path:     /home/andreasl/.docker/cli-plugins/docker-sbom
  scout: Docker Scout (Docker Inc.)
    Version:  v1.19.0
    Path:     /home/andreasl/.docker/cli-plugins/docker-scout

Server:
 Containers: 3
  Running: 2
  Paused: 0
  Stopped: 1
 Images: 14
 Server Version: 29.1.3
 Storage Driver: overlayfs
  driver-type: io.containerd.snapshotter.v1
 Logging Driver: json-file
 Cgroup Driver: cgroupfs
 Cgroup Version: 2
 Plugins:
  Volume: local
  Network: bridge host ipvlan macvlan null overlay
  Log: awslogs fluentd gcplogs gelf journald json-file local splunk syslog
 CDI spec directories:
  /etc/cdi
  /var/run/cdi
 Discovered Devices:
  cdi: docker.com/gpu=webgpu
 Swarm: inactive
 Runtimes: io.containerd.runc.v2 runc
 Default Runtime: runc
 Init Binary: docker-init
 containerd version: dea7da592f5d1d2b7755e3a161be07f43fad8f75
 runc version: v1.3.4-0-gd6d73eb8
 init version: de40ad0
 Security Options:
  seccomp
   Profile: builtin
  cgroupns
 Kernel Version: 6.12.54-linuxkit
 Operating System: Docker Desktop
 OSType: linux
 Architecture: x86_64
 CPUs: 14
 Total Memory: 47.29GiB
 Name: docker-desktop
 ID: 37e5ac23-777b-477d-bfe3-a610288bfb34
 Docker Root Dir: /var/lib/docker
 Debug Mode: false
 HTTP Proxy: http.docker.internal:3128
 HTTPS Proxy: http.docker.internal:3128
 No Proxy: hubproxy.docker.internal
 Labels:
  com.docker.desktop.address=unix:///home/andreasl/.docker/desktop/docker-cli.sock
 Experimental: false
 Insecure Registries:
  hubproxy.docker.internal:5555
  ::1/128
  127.0.0.0/8
 Live Restore Enabled: false
 Firewall Backend: iptables

Diagnostics ID

12119F1F-7419-4623-9DE2-2C026AB1C37B/20260125073747

Additional Info

No response