I am writing a simple nodejs container to forward requests on localhost to a port, the container exposes port 4433
docker build . -t myproxy
when i run the container by publishing ports like
docker run --rm -p 4433:4433 myproxy
I am able to access my server through http://localhost:4433 as expected but if i try to run the container with --network host i.e
docker run --rm --net host myproxy
I cannot access the container and get site cannot be reached error.
why is container not binding to my host network?
if i provide both options i.e.
docker run --rm --net host -p 4433:4433 myproxy
then i do get warning on console that
WARNING: Published ports are discarded when using host network mode which means it does recognize that i am trying to use host network.
OS: MAC
From the Docker docs:
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.
Related
I am trying to run the demonstration for docker, and host networking using:
docker run --rm -d --network host --name my_nginx nginx
When inspecting the running container using Docker Desktop, it show port 80 as not bound. Also, when navigating to http://localhost:80, I am not able to see the default nginx welcome. I am only able to see any application when I manually bind ports to the host machine; i.e -p 80:80. I did give myself a custom local IP address and DNS options (Windows 10). Do I need to modify my hosts file on my system?
I have an app listening on port 4000 and have a need to run it in a container with --net=host for simplified access to services on the host. According to docs and lots of similar questions about --net=host, I should be able to get to my app as easy as telnet localhost 4000, but that's not the case: the app in container is not accessible. If I run the container w/out --net=host and with -p 4000:4000, it works, but unfortunately I can't go with it.
Docker Version: 17.03.1-ce-mac5 (16048)
OS: OS X 10.12.4
docker run command: docker run --rm -it --net=host -v /app/dir:/opt/app --name app-dev bitwalker/alpine-elixir-phoenix:1.4.2 iex -S mix phx.server
Keep in mind that on Mac/Windows a thin VM is used as Docker needs a Linux kernel to operate. So using --net=host will not work as you expect, essentially this will use the host network of the VM. You should be able to verify this by accessing port 4000 of the docker VM.
For your use case I would recommend porting the other services to docker, if that is not an option running a local DNS resolver like dnsmasq should do the trick. Just let some domain names resolve to your Mac host ip.
I am running Docker for Mac. When I run
docker run -d --rm --name nginx -p 80:80 nginx:1.10.3
I can access Nginx on port 80 on my Mac. When I run
docker run -d --rm --name nginx --network host -p 80:80 nginx:1.10.3
I can not.
Is it possible to use both "--network host" and publish a port so that it is reachable from my Mac?
Alternatively, can I access Nginx from my Mac via the IP of the HyperKit VM?
Without the --network flag the container is added to the bridge network by default; which creates a network stack on the Docker bridge (usually the veth interface).
If you specify --network host the container gets added to the Docker host network stack. Note the container will share the networking namespace of the host, and thus all its security implications.
Which means you don't need to add -p 80:80, instead run...
docker run -d --rm --name nginx --network host nginx:1.10.3
and access the container on http://127.0.0.1
The following link will help answer the HyperKit question and the current limitations:
https://docs.docker.com/docker-for-mac/networking/
There is no docker0 bridge on macOS
Because of the way networking is implemented in Docker for Mac, you
cannot see a docker0 interface in macOS. This interface is actually
within HyperKit.
Im running Docker Desktop for Windows (hyper V) and I need to access docker daemon from the container via tcp. It is possible to connect to it from the host like:
curl -v 127.0.0.1:2375/info but not possible to access it from a container using my host IP address. Maybe someone knows how to do that or at least how to ssh to that docker vm, for example it is possible to ssh in to it on mac by executing:
screen ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/tty
I've figured how to do that using socat tool which takes docket.socket and proxy TCP calls to it.
So I've launched container with a socat which mount docker.sock since it is available inside of a VM and expose 2375 port:
docker run -p 2375:2375 -v /var/run/docker.sock:/var/run/docker.sock codenvy/socat -d -d TCP-L:2375,fork UNIX:/var/run/docker.sock
With that now, I'm able to access docker daemon API through socat container.
I have a CentOS docker container on a CentOS docker host. When I use this command to run the docker image docker run -d --net=host -p 8777:8777 ceilometer:1.x the docker container get host's IP but doesn't have ports assigned to it.
If I run the same command without "--net=host" docker run -d -p 8777:8777 ceilometer:1.x docker exposes the ports but with a different IP. The docker version is 1.10.1. I want the docker container to have the same IP as the host with ports exposed. I also have mentioned in the Dockerfile the instruction EXPOSE 8777 but with no use when "--net=host" is mentioned in the docker run command.
I was confused by this answer. Apparently my docker image should be reachable on port 8080. But it wasn't. Then I read
https://docs.docker.com/network/host/
To quote
The host networking driver only works on Linux hosts, and is not supported on Docker for Mac, Docker for Windows, or Docker EE for Windows Server.
That's rather annoying as I'm on a Mac. The docker command should report an error rather than let me think it was meant to work.
Discussion on why it does not report an error
https://github.com/docker/for-mac/issues/2716
Not sure I'm convinced.
The docker version is 1.10.1. I want the docker container to have same ip as the host with ports exposed.
When you use --net=host it tells the container to use the hosts networking stack. So you can't expose ports to the host, because it is the host (as far as the network stack is concerned).
docker inspect might not show the expose ports, but if you have an application listening on a port, it will be available as if it were running on the host.
On Linux, I have always used --net=host when myapp needed to connect to an another docker container hosting PostgreSQL.
myapp reads an environment variable DATABASE in this example
Like Shane mentions this does not work on MacOS or Windows...
docker run -d -p 127.0.0.1:5432:5432 postgres:latest
So my app can't connect to my other other docker container:
docker run -e DATABASE=127.0.0.1:5432 --net=host myapp
To work around this, you can use host.docker.internal instead of 127.0.0.1 to resolve your hosts IP address.
Therefore, this works
docker run -e DATABASE=host.docker.internal:5432 -d myapp
Hope this saves someone time!