docker port already allocated — how to fix

Q: Use a different host port

Map a different host port to the same container port: ``` # Map host port 8081 → container port 8080 docker run -p 8081:8080 my-image ```

Quick Answer

# Find what is using the port (e.g. 8080)
sudo lsof -i :8080
# or
ss -tlnp | grep 8080

# Stop the conflicting container
docker ps | grep 8080
docker stop <container-id>

# Or kill the non-Docker process
sudo kill -9 <PID>

When this happens

Error response from daemon: driver failed programming external connectivity on endpoint my-app:
Bind for 0.0.0.0:8080 failed: port is already allocated

Another process or Docker container is already listening on the same host port.

Other causes & fixes

Use a different host port

Map a different host port to the same container port:

# Map host port 8081 → container port 8080
docker run -p 8081:8080 my-image

Stop all containers on a given port

docker ps --filter "publish=8080" -q | xargs docker stop

On macOS: AirPlay Receiver uses port 5000 / 7000

Disable AirPlay Receiver in System Settings → General → AirDrop & Handoff.

# Verify
sudo lsof -iTCP:5000 -sTCP:LISTEN