Docker accessing the host network

One thing I have struggled with is having a docker container access the host network.

The documentation about host networking and host networking tutorial gives good insight in how to achieve this.

docker run -d --network host --name my_nginx nginx

I tried the above on my host that already had nginx running, looking at the log it failed with:

[cent@cent]$ docker logs 132738f47938
2019/05/29 07:02:23 [emerg] 1#1: bind() to failed (98: Address already in use)
nginx: [emerg] bind() to failed (98: Address already in use)
2019/05/29 07:02:23 [emerg] 1#1: still could not bind()
nginx: [emerg] still could not bind()

All I wanted to do was to figure out how to access the local machine, but getting a container to stay running is also a struggle.