I have two docker containers which runs on the same host(centos 6 server).
container 1 >> my web application (Ports mapped to some random port of host)
container 2 >> python selenium testscripts ( Runs headless Firefox)
My Test cases fails saying problem loading page
Basically the issue is that the second container or any other container residing on the same host is not able to access my Web application.
But my web app is accesible to outside world
I linked both containers and still i am facing the problem
I tried replicating the same setup in my laptop(ubuntu) and its working fine!!!
Any help appreciated !!
Thanks in advance
I think order matters in linking containers. You should start container1 the web application and then link container2 with webapp.
You need to change your selenium scripts to use the docker link id or alias as the hostname.
For example if you did:
$ sudo docker run -d --name webapp my/webapp
$ sudo docker run -d -P --name selenium --link webapp:webapp my/selenium
then your selenium scripts should point to http://webapp/
I had this problem in Fedora(22) - for some containers (not all). Upon inspection, it showed up there is an special DOCKER chain on the iptables, that can make some connections go loose. Appending an accept rule for that chain made things work:
sudo iptables -A DOCKER -p tcp -j ACCEPT
(While searching for the problem before hitting this question, there are suggestions this also occurs in CentOS and RHEL)
Yes the order of container launch does matter, But i am launching my web application container through jenkins.
jenkins is configured in container 2.
So i can not launch my web application(container 1) manually.
Is there anyother solution for this, something like bidirectional linkage??
Related
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.
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
1: docker run -d -p 3000:3000 images
If i up a localhost:3000 server in container，how can i open it in my machine browser, what's the ip?
I've tried localhost:3000 or 0.0.0.0:3000.
2: I use docker pull ubuntu and docker run it, after updating and deploying the server i commmited it.So now i have one ubuntu and a new image.
Next time i run a container using this new image，
The shell scripts still needs to be sourced, also the server needs to reopened again.
How can i commit the image that it can source the scripts and deployed by itself when i docker run it.
Thanks.
I don't quite understand questions 2 or 3, can you add more context?
Regarding your question about using -p, you should be able to visit in your browser using http://localhost:3000/ . However that assumes a couple of things are true.
First, you used -p 3000:<container-port> - looks good on this point.
Second, the image you have run exposed port 3000 (EXPOSE 3000).
And third, the service running in the container is listening on 0.0.0.0:3000. If it is listening on localhost inside the container, then the port export will not work. Each container has its own localhost which is usable only inside the container. So it needs to be listening on all IPs inside the container, in order for outside connections to reach the service from outside of the container.
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>.
I just started playing around with Docker and was able to setup a docker image using Ubuntu 14.03 / LXDE / VNC which works fine since I can connect from outside to the VNC server.
Now I am trying to understand the Networking of Docker but it seems I am completely lost. Since I had to forward the port for VNC already it seems that no further ports could be forwarded?
Assuming I have an application running under Wine which requires several portranges, how to achieve that? Does it mean that I would need to create a further container running the Wine application on top of the base image?
You can specify the -p option as often as you want
ie -p 8080-8085:8080-8085 -p 1234:1234 -p 9000-9005:9000-9005