I want to run a dockerized nginx on port 443 (https), but this seems to be taken by the docker-proxy.
Why is this, and can I do someting about it?
EDIT
The same conflict happens with the http port (80)
docker-proxy is run when you publish a port on the host. Look for the container or service you have run that is publishing the port and remove it:
$ docker container ls
$ docker service ls
Related
I would like to know how to unmount nginx server that appears on my port 8081.
I used this command:
docker run -d --name server -p 8081:80 nginx
However, I already stopped and removed nginx server with docker and deleted the image, but I still have port 81 busy with the server.
If you really don't have any docker container running you might have nginx installed on your system. Use one of the proposed ways here to identify the process running on 8081. You can then decide further moves like killing the processes pid.
I did it and apparently I don't have any process listening on port 8081, by default.
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
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've started using docker for dev, with the following setup:
Host machine - ubuntu server.
Docker container - webapp w/ tomcat server (using https).
As far as host-container access goes - everything works fine.
However, I can't manage to access the container's webapp from a remote machine (though still within the same network).
When running
docker port <container-id> 443
output is as expected, so docker's port binding seems fine.
172.16.*.*:<random-port>
Any ideas?
Thanks!
I figured out what I missed, so here's a simple flow for accessing docker containers webapps from remote machines:
Step #1 : Bind physical host ports (e.g. 22, 443, 80, ...) to container's virtual ports.
possible syntax:
docker run -p 127.0.0.1:443:3444 -d <docker-image-name>
(see docker docs for port redirection with all options)
Step #2 : Redirect host's physical port to container's allocated virtual port. possible (linux) syntax:
iptables -t nat -A PREROUTING -i <host-interface-device> -p tcp --dport <host-physical-port> -j REDIRECT --to-port <container-virtual-port>
That should cover the basic use case.
Good luck!
Correct me if I'm wrong but as far as I'm aware docker host creates a private network for it's containers which is inaccessible from the outside. That said your best bet would probably be to access the container at {host_IP}:{mapped_port}.
If your container was built with a Dockerfile that has an EXPOSE statement, e.g. EXPOSE 443, then you can start the container with the -P option (as in "publish" or "public"). The port will be made available to connections from remote machines:
$ docker run -d -P mywebservice
If you didn't use a Dockerfile, or if it didn't have an EXPOSE statement (it should!), then you can also do an explicit port mapping:
$ docker run -d -p 80 mywebservice
In both cases, the result will be a publicly-accessible port:
$ docker ps
9bcb… mywebservice:latest … 0.0.0.0:49153->80/tcp …
Last but not least, you can force the port number if you need to:
$ docker run -d -p 8442:80 mywebservice
In that case, connecting to your Docker host IP address on port 8442 will reach the container.
There are some alternatives of how to access docker containers from an external device (in the same network), check out this post for more information http://blog.nunes.io/2015/05/02/how-to-access-docker-containers-from-external-devices.html
I want to assign a container a port, so that it gets the same port after every restart of the container.
Example:
I have a container, which has an Apache in it. The Apache runs on port 80 inside the container.
Now, after starting the container, docker assigns a host port to the container port, for example: 49154 -> 80. But the host port changes after restart, depending on the number of running containers. I tried to specify the port in the config.json file of the container, but it gets overwritten.
Is it possible to specify the host port manually?
Thanks in advance and best regards,
Chris
Per the docker.io documentation: https://docs.docker.com/engine/userguide/networking/default_network/dockerlinks/
$ sudo docker run -p 80:80 <image> <cmd>
Default port redirects can be built into a container with the EXPOSE build command.
When you start docker, you can use the '-p' parameter.
docker run -p 80 yourimage apache2 will do what you currently have.
Now, you can specify ':' to make this port static:
docker run -p :80 -p :443 yourimage apache2
If you are using a Dockerfile with the EXPOSE instruction, it is the same thing :)