I have made my own Dockerfile for a apache server that starts with an standard parent file. See first line in my Dockerfile below:
FROM php:7.0-apache
EXPOSE 8080
This parent exposes port 80. Now have I exposed port 8080 in my Dockerfile. Only when I run it both ports are exposed.
It it posible to close the parent port 80 in my Dockerfile? As I cannot edit that file.
Unfortunately, this is currently impossible.
But you can follow this issue on Docker's GitHub. It's from 2014, but it is still Open. Never know...
As an alternative, rather than editing the configuration in the docker image you can also use port mapping to achieve the same result.
For example mapping port 8080 on the host to port 80 within the docker image, like so:
docker run -d -p 8080:80 image_name
Apart from telling docker to expose the port, you must configure apache to listen 8080, doing these two editions:
/etc/apache2/ports.conf
/etc/apache2/sites-enabled/000-default.conf
Dockerfile:
FROM php:7.0-apache
RUN sed -si 's/Listen 80/Listen 8080/' /etc/apache2/ports.conf
RUN sed -si 's/VirtualHost .:80/VirtualHost *:8080/' /etc/apache2/sites-enabled/000-default.conf
EXPOSE 8080
Then:
docker run -d -p 8080:8080 image_name
Edit:
About port 80. The port is not opened and it's not exposed if you use the previous command. If you don't see the ->80 symbol in docker ps, the port is not exposed:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
100fbb367226 php7 "docker-php-entryp..." 2 minutes ago Up 46 seconds 80/tcp, 0.0.0.0:8080->8080/tcp musing_snyder
And:
▶ docker inspect 100fbb367226 -f "{{json .NetworkSettings.Ports}}"
{"80/tcp":null,"8080/tcp":[{"HostIp":"0.0.0.0","HostPort":"8080"}]}
Related
I am creating a nginx container from dockerfile as shown below.
I have performed following sequence of steps.
Dockerfile content
FROM nginx
COPY . /usr/share/nginx/html
EXPOSE 80
Build docker image from Dockerfile
docker build -t mynginx
create user defined "bridge" network "my-bridge"
docker network create my-bridge
create nginx container in "my-bridge" network and exposed port 80 of nginx to
8084 port of host
docker run -itd --network my-bridge --name mynginxcontainer -p 8084:80 mynginx /bin/bash
when i try to access container using host port then nginx is not accesible
http://Public_IP_OF_EC2:8084
So the question is why am I not able to access nginx using host's port?
All steps looks good except docker run
you are providing /bin/bash as entrypoint which overwrites existing CMD for nginx.
Kindly start without /bin/bash should be working or provide valid entrypoint which start nginx service inside container.
I have a demo app which is hosted on docker. The exposed port for Docker is 80 and the app is running fine on local machine and I am able to see landing page for my app on localhost:8888.
Docker file is as given below
FROM microsoft/aspnetcore:2.0
COPY dist /app
WORKDIR /app
EXPOSE 80/tcp
ENTRYPOINT ["dotnet", "demoapp.dll"]
Whenever I change line "EXPOSE 80/tcp" to for ex- "EXPOSE 8080/tcp" , "EXPOSE 5000/tcp" etc to expose any other port except 80 of Docker container as given in many online available sample codes, I am unable to run my app on browser. Any port except 80 is not working.
I am able to create image and create container for application too. Everything goes well but when I try to run app on browser (localhost:8080/5000/9000 etc.) The app landing page doesn't load.
Any suggestions? Do I need to do some port related configuration or contact my network team? or any code which I am missing here?
You should be able to expose any port inside the container.
However you publish the exposed port on the host during the start of the container.
This is done with the -p flag of the docker run command.
When you say you are able to access the application using localhost:8888 it means you have run the docker run command with -p 8888:80. This publishes the container port 80 onto the host as port 8888.
To use any other port just change the docker run command to -p 8888:<new exposed port> and that should do it.
See the docker run command help for more info:
https://docs.docker.com/v17.12/edge/engine/reference/commandline/run/#publish-or-expose-port--p-expose
Publish or expose port (-p, –expose)
$ docker run -p 127.0.0.1:80:8080 ubuntu bash
This binds port 8080 of the container to port 80 on
127.0.0.1 of the host machine. The Docker User Guide explains in detail how to manipulate ports in Docker.
If your application runs at port suppose 8080 then make sure to do port mapping while running the container.
docker run -itd -p 8080:8080 <image>
This will map port 8080 of host on port 8080 inside the container. (-p hostport:containerport)
If you don't want port mapping then run docker container in host mode.
docker run -itd --net=host <image>
In this case your container use host network, so whatever port your application is running inside it should get exposed.
For microsoft/aspnetcore, it sets the ASPNETCORE_URLS environment variable to http://+:80 which means that if you have not explicity set a URL in your application, via app.UseUrl in your Program.cs for example, then your application will be listening on port 80 inside the container.
Reference: microsoft/aspnetcore
If you want to change the default port 80, you need to use UseUrls in Program.cs with like below, and use EXPOSE 8080/tcp in dockerfile.
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.UseUrls("http://+:8080")
.UseStartup<Startup>();
Or, you need to change ASPNETCORE_URLS environment like
FROM microsoft/aspnetcore:2.0
COPY dist /app
WORKDIR /app
EXPOSE 8080/tcp
ENV ASPNETCORE_URLS=http://+:8080
ENTRYPOINT ["dotnet", "demoapp.dll"]
Command to run
docker run -it -p 8080:8080 mytest
Is it possible to config the port number in docker under "host mode"?
I wanna bind the application to 5050 port instead of 80 port .
However, when I run below script, it will default bind in 80 port:
sudo docker run --name=myname --network host -d webapi:1.0.0 --restart=always
So I tried to run with "-p 5050", for example
sudo docker run --name=myname --network host -d webapi:1.0.0 --restart=always -p 5050
sudo docker run --name=myname --network host -d webapi:1.0.0 --restart=always -p 5050:5050
Unfortunately, my Linux terminal returned with :
WARNING: Published ports are discarded when using host network mode
The docker image looks like something like this:
https://learn.microsoft.com/en-us/aspnet/core/host-and-deploy/docker/building-net-docker-images?view=aspnetcore-2.2
And my Dockerfile looks like this:
FROM microsoft/dotnet:2.1-aspnetcore-runtime
WORKDIR /publish
COPY . .
EXPOSE 5050
ENTRYPOINT ["dotnet", "WebApi.dll"]
Easy way out would be to run your application on 5050 port. Once your container is up & running you must be able to access your app on port 5050 on Docker host. You need not to bind any kind of ports because you are using the host network itself.
Thanks user "#atline" for the answer.
Only 80 port is allowed.
More reference is found here:
https://docs.docker.com/network/host/
What is the different between the following commands when creating a container in docker?
docker run -d -p 8080 sample/image
and
docker run -d -p 8080:8080 sample/image
I have seen majority of them use the second command, but I am not sure if they mean different things, or if the first is shorthand.
I couldn't find any material on this.
docker run -d -p 8080 sample/image
Exposes port 8080 of the container as an arbitrary port on the host. Which port that is is up to Docker.
Whereas,
docker run -d -p 8080:8080 sample/image
Exposes port 8080 of the container as port 8080 on the host.
In both cases, you can see the mapping using docker inspect, or even docker ps:
380af8c2bcc6 ubuntu "bash" 15 seconds ago Up 13 seconds 0.0.0.0:32768->1234/tcp elegant_meitner
In this case, port 1234 of the container is exposed as port 32768 on the host.
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 :)