vLLM and openweb UI both run on same machine in docker. open-webui docker container and vllm in vllm_download_and_serve10.
the openweb UI is accissible from 192.168.49.137
and the vllm docker has started with port 8000:8000. Vllm is accessible from outside app.
Openweb UI just cant reach it
This is a Docker networking issue: by default, localhost inside a Docker container refers to the container itself, not the host or other containers. To allow Open WebUI to reach the vLLM server, you should either (1) set the OPENAI_API_BASE_URL in the Open WebUI container to use the host’s IP (e.g., http://192.168.49.137:8000/v1), or (2) run both containers with --network host and remove port mappings, so they share the host network stack. This allows inter-container communication via the host’s IP and ports, resolving the connectivity problem according to vllm-project/vllm#10322.
If you use --network host, do so for both containers and remove -p port mappings. Alternatively, if you keep bridge networking, always use the host’s IP address, not localhost, in the Open WebUI’s environment variables. You can verify vLLM is reachable from the Open WebUI container by running curl http://192.168.49.137:8000/health inside the container. Would you like a step-by-step example of the Docker commands?
Sources:
curl http://192.168.49.137:8000/health
does not show anything. The vllm answers for app calling
If curl http://192.168.49.137:8000/health from inside the Open WebUI container does not return anything, but vLLM responds to external app calls, it means the container cannot reach the vLLM service via the host IP. This is a Docker network isolation issue: containers on the default bridge network cannot access the host via its IP unless special configuration is used. According to vllm-project/vllm#10322, the recommended solution is to run both containers with --network host and remove -p port mappings, so they share the host network and can communicate via 192.168.49.137.
Would you like detailed Docker run commands for this setup?
Sources: