Host network driver
If you use the
host network mode for a container, that container's network
stack isn't isolated from the Docker host (the container shares the host's
networking namespace), and the container doesn't get its own IP-address allocated.
For instance, if you run a container which binds to port 80 and you use
networking, the container's application is available on port 80 on the host's IP
Given that the container does not have its own IP-address when using
hostmode networking, port-mapping doesn't take effect, and the
--publish-alloption are ignored, producing a warning instead:
WARNING: Published ports are discarded when using host network mode
Host mode networking can be useful for the following use cases:
- To optimize performance
- In situations where a container needs to handle a large range of ports
This is because it doesn't require network address translation (NAT), and no "userland-proxy" is created for each port.
The host networking driver only works on Linux hosts, and is not supported on Docker Desktop for Mac, Docker Desktop for Windows, or Docker EE for Windows Server.
You can also use a
host network for a swarm service, by passing
docker service create command. In this case, control traffic (traffic
related to managing the swarm and the service) is still sent across an overlay
network, but the individual swarm service containers send data using the Docker
daemon's host network and ports. This creates some extra limitations. For instance,
if a service container binds to port 80, only one service container can run on a
given swarm node.