Description

Fixes WebSocket connection failures when accessing OpenHands from a remote browser.

Problem

When accessing OpenHands from a remote machine, WebSocket connections fail with:

Firefox can't establish a connection to the server at ws://localhost:42295/sockets/events/...

The browser is on a different machine than the server, so localhost is incorrect.

Root Cause

The DOCKER_HOST_ADDR environment variable is not passed from the main OpenHands container to spawned runtime and agent-server containers, causing them to default to localhost for URL construction.

Solution

This PR adds code to pass DOCKER_HOST_ADDR to runtime and agent-server containers, allowing existing code in sandbox_config.py, docker_runtime.py, and config.py to correctly use the server IP address for WebSocket and API URLs.

Changes

1. File: openhands/runtime/impl/docker/docker_runtime.py

   • Lines: 475-477
   • Change: Pass DOCKER_HOST_ADDR from main container to runtime containers

2. File: openhands/app_server/sandbox/docker_sandbox_service.py

   • Lines: 313-315
   • Change: Pass DOCKER_HOST_ADDR from main container to agent-server containers

Testing ✅

Deployment Test (OpenHands 1.0):

• Server: 192.168.1.206
• Client: Remote mobile browser (192.168.1.175)
• Command: docker run -e DOCKER_HOST_ADDR=192.168.1.206 -p 3000:3000 ...

Results:

✅ Agent-server containers receive DOCKER_HOST_ADDR=192.168.1.206

✅ All generated URLs use 192.168.1.206 instead of localhost:

http://192.168.1.206:42015/api/conversations/...
http://192.168.1.206:52051/... (VSCode)
http://192.168.1.206:57233/... (worker)
http://192.168.1.206:39157/... (worker)

✅ Remote browser successfully connects to correct IP addresses

✅ No Python import errors

✅ Container starts and runs normally

Before this fix: All URLs showed localhost, causing connection failures from remote browsers

After this fix: All URLs show the actual server IP, enabling remote access

Related Issues

• Related to Update docker_runtime.py #8422 #8423 (previous fix for old architecture - not ported to v1.0)
• Complements add support of DOCKER_HOST_ADDR #7593 (DOCKER_HOST_ADDR support)

Environment Variable Flow

Host System (-e DOCKER_HOST_ADDR=<ip>)
    ↓
OpenHands-app Container
    ↓ [THIS FIX]
Runtime & Agent-Server Containers
    ↓
URLs use server IP instead of localhost

Backward Compatibility

• If DOCKER_HOST_ADDR is not set, behavior is unchanged (defaults to localhost)
• No breaking changes
• Works with local and remote deployments

Note

A separate CORS configuration issue was discovered during testing (unrelated to this fix) where agent-server containers need CORS headers to allow cross-origin requests from the main app. This will be addressed in a separate PR.