Docker didn't forward the port from web service - docker

I'm using ASP Core image to create a new container.
I've developed simple service which uses port 5000.
Now I created Dockerfile and built container which exposes
EXPOSE 5000
Running this container with a command
docker run -it -p 8080:5000 <name>
or even
docker run -it -p 127.0.0.1:8080:5000 <name>
doesn't lead to navigation to the 127.0.0.1:8080. So my browser says this site can't be reached.
p.s. I've checked the service without docker - it works correctly
UPD1
docker ps
shows my launched container with ports mapping information:
127.0.0.1:8080->5000/tcp
UPD2
this is netstat output from the host
tcp 0 0 localhost:5000 *:* LISTEN
lynx 127.0.0.1:5000 shows 200 OK
netstat -a on a client box doesn't show 8081 port or 5000
UPD3
I've just created a new container for NodeJs using public image.
Created a simple server with exposed port. After running it works as expected.
Actually it looks like the problem with exact Asp image

Which OS are you using? If you're running on OSX or Windows you will need to use the IP of your boot2docker virtual machine, not 127.0.0.1.
docker-machine ip will show you the IP of your current host.

Related

Networking using the host network, for docker not working

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 can't access my Docker container on GCP Compute Engine

I have my Docker container running on GCP Compute Engine. The CE server is running on CentOS 7. My Docker container has the application being served by Nginx with port 80 exposed. For some reason, I can't access it from the external IP address on my browser.
I ran the container with this command:
sudo docker run --name myapp -p 80:80 -d myapp:1.0.0
When I do sudo curl <internal_ip>:80 or sudo curl <localhost>:80 it will show that the application is running and returns back the content, but if I try to access in my browser with <external_ip>:80, it doesn't load anything. What can I do to make this accessible through the external IP address?
It seems I had to configure the firewall to open up port 80.

Cannot contact docker container on Windows host

tl;dr summary of the problem:
Application launches successfully within container, binds to 127.0.0.1:8080 within the container, and successfully services web requests, but only within the container
docker ps -a confirms that port 8080 is being exposed
I cannot communicate with the application from the host using the container's actual IP address when I request http://[Container IP address]:8080
The host is running Windows 10
The Windows Firewall is completely disabled for troubleshooting
To troubleshoot I have created the simplest possible application to run in a dockers container, an F# / Suave application like so:
open Suave
[<EntryPoint>]
let main args =
startWebServer defaultConfig (Successful.OK "Hello World!")
0
Which works fine, returning a simple "Hello World!" when I run it locally.
To containerize the app I have followed the instructions at "Dockerize a .NET Core application" which instructs me to run the container like
$ docker run -d -p 8080:80 --name myapp aspnetapp
I cannot connect to the "website" at http://localhost:80 nor http://localhost:8080, which apparently is a common problems for Docker users running Windows. However the solution that seems to have fixed this problem for every other Windows user on the internet, running
docker inspect myapp
and then hitting the resulting IPAddress, does not work either. I get:
Hitting both http://172.17.0.2:80 and http://172.17.0.2:8080 in Chrome gives me "Site can't be reached."
Also worth noting, when I run
docker logs myapp
The only line is
[17:43:21 INF] Smooth! Suave listener started in 73.476ms with binding 127.0.0.1:8080
As a guess, I have also tried
ipconfig
and then hitting the IP address of the Docker NAT adapter, but this also results in an unreachable site.
UPDATE:
Another observation which might or might not be relevant: Many online tutorials suggest that under Windows you need to directly connect to the IP Address of the container, and to get that IP address by running
docker inspect -f "{{ .NetworkSettings.Networks.nat.IPAddress }}" myapp
which for me, always yields:
When I run a vanilla
docker inspect myapp
the resulting JSON is not structured exactly like the recommended query. I get a bridge node, but no nat node:
Your app says it’s bound to localhost:8080, but you’re publishing port 80. Stop the container, and rerun with:
docker run -d -p 8080:8080 --name myapp aspnetapp
Try adding the following lines in docker file
ENV ASPNETCORE_URLS http://+:80
EXPOSE 80
Reference: https://www.sep.com/sep-blog/2017/02/20/hosting-asp-net-core-docker/
My containerized app needed to listen/bind to 0.0.0.0 rather than 127.0.0.1.

docker running splash container but localhost does not load (windows 10)

I am following this tutorial to use splash to help with scraping webpages.I installed Docker toolbox and did these two steps:
$ docker pull scrapinghub/splash
$ docker run -p 5023:5023 -p 8050:8050 -p 8051:8051 scrapinghub/splash
I think it is running correctly, based on the prompted message in Docker window, which looks like this:
However, when I open the `localhost:8050' in a web browser, it says the localhost is not working.
What might have gone wrong in this case? Thanks!
You have mapped the port to your docker host (the VM), but you have not port-forwarded that same port to your actual "localhost" (your Windows host)
You need to declare that port-forwarding in the Network settings of your VM (for instance "default"), or with VBoxManage controlvm commands.
Then and only then could you access that port (used by your VM) from your Windows host (localhost).
That or you can access that same port using the IP address of your boot2docker VM: see docker-machine ls.
#user3768495, when you use http://192.168.99.100:8050/ , you are actually using the docker-machine ip and this ip would be available on your machine only and not on the network. To map it to localhost, you do need to port-forward the same port to your localhost. I was having the same issue and I detailed the process in below link.
https://stackoverflow.com/a/35737787/4820675

Remote access to webserver in docker container

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

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