OpenUxAS-SoI/docker/00c_README_OS_Differences.md

Operating System Differences

Overview

As we discover them, we will document import differences in how Docker operates on different operating systems.

Container/Host Network Communications

Docker has implemented a powerful set of network communication implementations that facilitate connecting containers and services. Unfortunately, communications from inside containers to host applications are implemented differently on LINUX, Windows, and MACOS. This means that communincation between UxAS, inside a container, and AMASE running on a host system is implemented differently for each of these OS's.

• LINUX OS the simplest method to communicate from inside the container to the host, and beyond, with LINUX is the use the option, --network host, when creating the Docker container. This maps the host network to the container network. This makes it possible to run UxAS as if it was not inside a Docker container, for example, the network device can be accessed by Zyre to broadcast heartbeats.

• Windows OS this implementation uses a bridge network for communication from the container to the host. The host ports are only accessable to the applications in the container through the gateway IP address on the bridge. To find the gateway IP address: -- open the Docker settings: Open the Docker for Windows menu by right- clicking the Docker icon in the Notifications area (or System tray), Select Settings. -- select the Network tab (on the left side of the dialog window) -- use the Internal Virtual Switch Subnet Address and change the last octet to 1. For example if the subnet addrees is 10.0.75.0, then the gateway IP address is 10.0.75.1 To configure communcation between containerized UxAS and AMASE use an address such as tcp://10.0.75.1:5555

• MACOS this implementation does not connect direcly to a bridge which make finding the required gateway address difficult. So far, the best way that I have discovered to find the gateway address is to look it up using the special Docker address, host.docker.internal, and a simple Docker container, for example: docker run --rm alpine nslookup host.docker.internal In this case, my returned address was 192.168.65.2 and the address used to communicate with AMASE was 192.168.65.2:5555

NOTE: At this point, I have not been able to access the network device directly inside the containers on Windows and MACOS. So at this point Zyre won't be able to send out broadcast heartbeats and thus will not operate correctly.

Zyre does work from inside the LINUX containers.

NOTE: firewalls can block communication between applications in containers and those running on the host