I have a running Docker container which shows PORTS 9191/tcp. So on my browser, I tried accessing server using localhost:9191/api/.... However, browser throws an error This site can’t be reached
Here is a log to docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c214aefed15e shah "youtube-dl-server -…" 6 seconds ago Up 5 seconds 9191/tcp boring_swirles
This is what my docker file looks like
FROM mariozig/youtube-dl_server
RUN pip install --pre youtube_dl_server
EXPOSE 9191
ENTRYPOINT ["youtube-dl-server", "--host=0.0.0.0"]
You have not mapped the docker container port to host port.
The docker container runs on a host. And The host doesn't know which requests to be directed to the docker container. For that you have to to map the host port to docker container port using -p flag in docker run command as shown below:
docker run -d -p HOST_PORT:CONTAINER_PORT IMAGE_NAME
-p in this command will specify that you are forwarding your host port to the container port. In your local host in the port HOST_PORT will call the port CONTAINER_PORT of your container.
Now when you will access the HOST_IP:HOST_PORT then the host will redirect the request to corresponding container with which this HOST_PORT has been mapped.
For example I started a tomcat docker container and mapped the tomcat container's 8080 port to host's 9092 port by using the above command. When I do docker ps I can see the mapping under PORTS as 0.0.0.0:9092->8080/tcp
Related
In my workplace docker is running behind firewall, only the port that is meant to serve webpage is excluded by rule.
The container starts but website does not open for same port.
If I host the website from machine running container using python -m SimpleHTTPServer it works.
docker container run --restart=always -p 8081: 8082 -it vue-js-app: latest
From the Docker documentation:
Publish or expose port (-p, --expose)
$ docker run -p 127.0.0.1:80:8080/tcp ubuntu bash
This binds port 8080 of the container to TCP port 80 on 127.0.0.1 of
the host machine. You can also specify udp and sctp ports. The Docker
User Guide explains in detail how to manipulate ports in Docker.
$ docker run --expose 80 ubuntu bash
This exposes port 80 of the container without publishing the port to
the host system’s interfaces.
And, from the Docker User Guide:
You also saw how you can bind a container’s ports to a specific port
using the -p flag. Here port 80 of the host is mapped to port 5000 of
the container:
$ docker run -d -p 80:5000 training/webapp python app.py
So, as an example of how to expose the ports you can use:
docker container run --restart always -p 8081:8082 -it vue-js-app:latest
My docker container (sctp server) is running on sctp with port number 36412. However, my sctp client on the host machine unable to communicate with the container. How do I expose this port from container to host? Is it not same as TCP/UDP?
When I run docker run -p 36412:36412 myimage, I get below error.
Invalid proto: sctp
From reading source code, the general form of the docker run -p option is
docker run -p ipAddr:hostPort:containerPort/proto
Critically, the "protocol" part of this is allowed to be any of tcp, udp, or sctp; it is lowercased, and defaults to tcp if not specified.
It looks like for your application, you should be able to
docker run -p 36412:36412/sctp ...
Use the -p flag when running to to map an open port on your host machine to the container port. The below example maps port 36412 on the host to 36412 in the container.
docker run -p 36412:36412 mysctpimage
To view the ports running on your container and where they are mapping to:
docker port <containerId>
This will tell you what port and protocol the container is mapping to your host machine. For example running a simple WebApi project may yield:
80/tcp -> 0.0.0.0:32768
Docker Port Documentation
How to publish or expose a port when running a container
When i run a container for a web-application that listens on port 8090
With
docker run -p 8090:8090 -h=%ComputerName% mycontainer
Then i can access the services on http://localhost:8090
If i started the container with
docker run --net="host" -h=%ComputerName% mycontainer
Then i can't access to the services on http://localhost:8090
Why ??
Is not supposed that with -net="host" the container shares the network of the host, then why i can't access to http://localhost:8090 with --net="host"
This is not what --net=host does.
In your first example; you are mapping the ports of the container to your host - which allows you to via the services of the container.
In the second example; you remove the -p option so no ports are now mapped.
What the --net=host does - is allows your container to view port on the host machine as if they were local to the container. So say you had a database running on port 5000 of your host machine, and it was not in a Docker container - you would be able to access this on the container via localhost:5000. (Note - there are some caveats to this; such as Docker for Mac would actually need docker.for.mac.localhost)
I have a two HTTP servers on my host machine; one listening on 8080, the other listening on 8081. The 8080 is a webapp, and the 8081 is an API.
I also have a Docker container that should connect to the webapp on 8080 using an automated tool, and that webapp should make HTTP requests to the API that's on 8081.
Here is a visual representation of what I want:
Host machine HTTP 8080
⇩ ⇖
⇧ Docker container
Host machine HTTP 8081
The problem I'm having is that the Docker container cannot connect to the website on the host machines 8080. I'm not sure why, because I set the --network=host flag, so shouldn't it be using the host machines network?
This is my Docker image:
## Redacted irrelevant stuff...
EXPOSE 8080 8081
This is how run the container:
docker run -d -p 8080:8080 -p 8081:8081 --network=host --name=app app
Any ideas what's wrong with my setup?
So you have two services running directly on the machine and you want to deploy a Docker container that should connect to one of those services.
In that case, you shouldn't map those port to the container and you shouldn't expose those ports in the Dockerfile as those ports are not for the container.
Remove the Expose ports from the Dockerfile
Start the container using docker run -d --network=host --name=app app. The container should be able to access the services using localhost:8080.
I have apache installed inside a running ubuntu:14.04 container. How to access this in the browser of the host machine? The address showing inside the container is, 172.17.0.2. Please help.
By default, the apache httpd image exposes the port 80
docker run -it --rm --name my-apache-app -v "$PWD":/usr/local/apache2/htdocs/ httpd:2.4
So http://localhost should be enough.
In your case, make sure:
the httpd is actually running (docker exec -it <yourContainer> bash: ps -eaf),
you have mapped the port you are running Apache in your container to the host (-p 80:80 for instance).
By default, the apache image exposes the port 80, but you need config this in run command (-p):
docker run -d -p 80:80 httpd
The first number is port of Docker Host and the second one is port of container. This configuration will map all connections to port tcp 80 of docker host to the same port of container.
After that you can access your application in your browser, using 127.0.0.1, localhost or other IP Address of your interface.