Connecting docker containers and host networking
Docker is great, but network namespaces are hard. By default docker doesn't like to share it's namespace info with the system. That makes it hard to use an ip netns command to inspect it.
Even if you were able to get a process into the network namespace, that's not really that useful because now it can't listen on the host socket to connect to it.
This tool makes it so that you can have one tool that connects a port inside a docker container to the host network.
There are two thread pools. The host and the namespace. Any incoming request is processed by the host threadpool. When a connection is made, the tool creates a new connection on the namespace threadpool to the designated target. The tool will then shuffel data transparently container was running on the hosts IP address.
Assuming both ns-net-bridge and the connect script are on the PATH on the TARGET machine.
export PORT=8080
ssh -L $PORT:127.0.0.1:$PORT $TARGET
docker ps # find the docker container id
connect $DOCKER_ID $PORT
And you will now be able to access something on port 8080 from your local machine and have it routed to the docker container.