Access service running in a container from browser - docker

I'm using docker to run a test environment locally On Ubuntu 16.04. I spin up a container using the command -
fwx#asus:~$ docker run -p 3000:3000 -v ~/work/website/:/website -it test-env bash
This puts me inside the container where I do some initial setup and start the service like so -
root#c98d858cb1a4:/website# start-service
The service is configured to the endpoint http://127.0.0.1:3000/ and docker inspect on the container provides me the IP address 172.17.0.2.
As I understand from the multiple blog / forum posts addressing similar issues, I should be able to access the pages served through a browser on my host at http://172.17.0.2:3000. However, trying to access it thusly throws a connection error that the website cannot be reached.
I have tried various solutions proposed on similar questions including adding 172.17.0.0 to the route, but to no avail. Can someone please tell me what I'm doing wrong?

Whenever you create a docker container it will be assigned a private ip, To access the container you need to expose it which in your case is -p 3000:3000 try accessing the service from your host ip address and also try by disabling firewall.

Related

Docker cannot access exposed port inside container

I have a container for which I expose my port to access a service running within the container. I am not exposing my ports outside the container i.e. to the host (using host network on mac). On getting inside the container using exec -t and running a curl for a post request, I get the error:
curl command: curl http://localhost:19999
Failed connect to localhost:19999; Connection refused.
I have the expose command in my dockerfile and do not want to expose ports to my host. My service is also up and running inside the container. I also have the property within config set as
"ExposedPorts": {"19999/tcp": {}}
(obtained through `docker inspect <container id/name>\ Any idea on why this is not working? Using docker for Mac
I'd post my docker-compose file too but this is being built through maven. I can ensure that I am exposing my port using 19999:19999. Another weird issue is that on disabling my proxies it would run a very light weight command for my custom service and wouldn't run it again returning the same error as above. The issue only occurs on my machine and not others
Hints:
The app must be listening on port 19999 which is probably not.
The EXPOSE that you're using inside the Dockerfile does nothing.
Usually there is no need to change the default port on which an application is listening, hence each container has its own IP and you shouldn't run in a port conflict.
Answer:
Instead of curling 19999 try to use the default port on which your app would normally be listening to(it's hard to guess what you are trying to run).
If you don't publish a port (with the docker run -p option or the Docker Compose ports: option), you cannot directly reach the container on Docker for Mac. See the Known limitations, use cases, and workarounds in the Docker Desktop for Mac documentation: the "per-container IP addressing is not possible" item ism what you're trying to attempt.
The docker inspect IP address is basically useless, except in one very specific Docker configuration (on a native-Linux host, calling from outside of Docker, on the same host); I wouldn't bother looking it up.
The Dockerfile EXPOSE directive and similar runtime options do very little and mostly serve as documentation. Even if you have that configured you still need to separately publish the port when you start the container to reach it from outside of Docker space.

Simple Nginx server on docker returns 503

I'm just starting up with Docker and the first example that I was trying to run already fails:
docker container run -p 80:80 nginx
The command successfully fetches the nginx/latest image from the Docker Hub registry and runs the new container, there is no indication in CMD of anything going wrong. When I browse to localhost:80 I get 503 (Service Unavailable). I'm doing this test on Windows 7.
I tried the same command on another computer (this time on macOS) and it worked as expected, no issues.
What might be a problem? I found some issues on SO similar to mine, but they were connected with the usage of nginx-proxy, which I don't use and don't even know what it is. I'm trying to run a normal http server.
//EDIT
When I try to bind my container to a different port, for example:
docker container run -p 4201:80 nginx
I get ERR_CONNECTION_REFUSED in Chrome, so basically connection can't be established, because destination does not exist. Why is that?
The reason why it didn't work is that on Windows, Docker publishes results on different IP than localhost. This IP given is at the top in Docker client console.

How to provide internet access to running docker container?

Hi can any one help me to tell the correct command to provide internet access to a running container ?
I know we have to specify --net in docker run command to access internet from inside container.
What if I want to provide internet access to container which I didn't ran with --net command (i.e to container which does not have internet access)
I got docker network connect NetworkName ContainerName/ID command from: https://docs.docker.com/engine/reference/commandline/network_connect/
but running above command does not providing internet access so requesting to share me correct command.
Note: Am trying this on centos container
Your docker containers should have internet access by default as that is the normal setup of docker, and by no means should they require providing --net to get that. If they don't then you probably have something mixed up on your host like ie. additional firewall rules or lack of ip forwarding enabled.
For starters, check if you have enabled ip forwarding, should look like following :
$ cat /proc/sys/net/ipv4/ip_forward
1
and verify if you don't have something funky in your iptables
Docker containers should resolve internet traffic once you configured properly. Please check the container network status by,
Enter public DNS (8.8.8.8)manually in /etc/resolve.conf.
If not working check the container network side.
#goto /etc/default/docker
#add public DNS values there (DOCKER_OPTS="--dns 208.67.222.222 --dns 208.67.220.220")
#sudo service docker restart
Login to the container and ping google.com

localhost not working docker windows 10

I am using VS2017 docker support. VS created DockerFile for me and when I build docker-compose file, it creates the container and runs the app on 172.x.x.x IP address. But I want to run my application on localhost.
I did many things but nothing worked. Followed the docker docs as a starter and building microsoft sample app . The second link is working perfectly but I get HTTP Error 404 when tried the first link approach.
Any help is appreciated.
Most likely a different application already runs at port 80. You'll have to forward your web site to a different port, eg:
docker run -d -p 5000:80 --name myapp myasp
And point your browser to http://localhost:5000.
When you start a container you specify which inner ports will be exposed as ports on the host through the -p option. -p 80:80 exposes the inner port 80 used by web sites to the host's port 80.
Docker won't complain though if another application already listens at port 80, like IIS, another web application or any tool with a web interface that runs on 80 by default.
The solution is to:
Make sure nothing else runs on port 80 or
Forward to a different port.
Forwarding to a different port is a lot easier.
To ensure that you can connect to a port, use the telnet command, eg :
telnet localhost 5000
If you get a blank window immediatelly, it means a server is up and running on this port. If you get a message and timeout after a while, it means nobody is running. You anc use this both to check for free ports and ensure you can connect to your container web app.
PS I run into this just a week ago, as I was trying to set up a SQL Server container for tests. I run 1 default and 2 named instances already, and docker didn't complain at all when I tried to create the container. Took me a while to realize what was wrong.
In order to access the example posted on Docker Docs, that you pointed out as not working, follow the below steps,
1 - List all the running docker containers
docker ps -a
After you run this command you should be able to view all your docker containers that are currently running and you should see a container with the name webserver listed there, if you have followed the docker docs example correctly.
2 - Get the IP address where your webserver container is running. To do that run the following command.
docker inspect -f "{{ .NetworkSettings.Networks.nat.IPAddress }}" webserver
You should now get the IP address which the webserver container is running, hope you are familiar with this step as it was even available within the building Microsoft sample app example that you attached with the question.
Access the IP address you get once running the above command and you should see the desired output.
Answering to your first question (accessing docker container with localhost in docker for windows), in Windows host you cannot access the container with localhost due to a limitation in the default NAT network stack. A more detailed explanation for this issue can be obtained by visiting this link. Seems like the docker documentation is not yet updated but this issue only exists in Windows hosts.
There is an issue reported for this as well - Follow this link to see that.
Hope this helps you out.
EDIT
The solution for this issue seems to be coming in a future Windows release. Yet that release comes out this limitation is available in Windows host. Follow this link -> https://github.com/MicrosoftDocs/Virtualization-Documentation/issues/181
For those who encountering this issue in 2022, changing localhost to 127.0.0.1 solved an issue for me.
There is other problem too
You must have correct order with parameters
This is WRONG
docker run container:latest -p 5001:80
This sequence start container but parameter -p is ignore, therefore container have no ports mapping
This is good
docker run -p 5001:80 container:latest

Port binding is not working in docker on windows

I have installed docker on my Windows m/c.
I am trying to install Gerrit on that.
Pull image is done-Successfully
Run image is also done -->
docker run -d -p 8080:8080 -p 29418:29418 ******/gerrit
I try to connect it through browser with my container id:8080 but it throws error
This site can’t be reached
What is oing wrong.. Please help with suggestions.
BR,
Rash
You need to access your container by IP of virtual machine. You can obtain it with command: docker-machine ls. Then access container in browser by (replace ip) http://192.168.99.100:8080
This is a known limitation of windows containers at the moment as per the docker documentation (https://docs.docker.com/docker-for-windows/troubleshoot/#limitations-of-windows-containers-for-localhost-and-published-ports).
As of Windows 10 Creator's update this has kinda been fixed where you can use host IP with the bounded host port(http://<hostIp>:<hostBoundedPort>), but still not localhost or any of it's aliases.
Alternatively you can avoid port mapping hit the container IP directly. There is numerous ways to get your container IP. Personally I would use:
docker ps
This lists out all the the running docker containers allowing you to find the Container ID for the container that you want to hit followed by:
docker inspect <initial_part_or_full_id>
This will output low level information about the container, including it's Network settings where you will find the NAT-ed endpoint details containing the IP. Then simply http://<containerIP>:<containerPort>.

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