Say we have frontend and backend containers based on Docker Desktop (for Windows).
Backend container uses port 9001, and the frontend container listens to 9001.
The problem is that port 9001 is already in use by Windows 10 by the Intel driver, and it is impossible to run a container on this port:
Error response from daemon: Ports are not available: listen tcp 0.0.0.0:9001: bind: An attempt was made to access a socket in a way forbidden by its access permissions.
Could you please advise what is the way to handle this port if there is no ability to change it directly from application code?
A couple of ways:
When either using a docker run command, specify the host port to use, and set it to something other than 9001. i.e. -p 9002:9001 or Docker Compose, i.e.
ports:
- '9002:9001'
Then use port 9002 instead of 9001 when accessing the container from the host (Win 10).
Use Nginx and set up a reverse proxy, leave the host port empty when starting the container so no external post is opened on the host, and have the reverse proxy pass it over to the container's 9001 port.
Related
I have set up a couple of containers that interact with each other. The main application container runs on --network = host because it queries several mySQL containers running on different ports exposed on the host network.
I am trying to hit the application on the host but get an error:
curl: (7) Failed to connect to 0.0.0.0 port 36081: Connection refused
I am working on Docker installed on MacOS.
I have read several questions that indicate that docker on MacOS runs on a VM. But what is the workaround to access the application from the host? Any way to get the IP of the said VM?
You cannot use --network=host on Mac to connect via host ports but binding to host port using -p options works.
https://docs.docker.com/docker-for-mac/networking/#/there-is-no-docker0-bridge-on-osx
I WANT TO CONNECT TO A CONTAINER FROM THE MAC
Port forwarding works
for localhost; --publish, -p, or -P all work. Ports exposed from Linux
are forwarded to the host.
Our current recommendation is to publish a port, or to connect from
another container. This is what you need to do even on Linux if the
container is on an overlay network, not a bridge network, as these are
not routed.
For your use case,
You need to create a docker network and attach both the DB and application containers to this network. Then the containers will be able to talk to each other by their name. You can also publish the application container port so that you can access it from your host.
https://docs.docker.com/network/bridge/
Instead of creating the network, attaching the containers to the network etc manually, you can use docker-compose.
https://docs.docker.com/compose/
I have created a Google compute instance with Container-optimized-OS image.
I have configured the firewall to allow http and https.
I am using the docker image with spring boot application which connects to cloudsql. When I use run command on compute engine instance ssh, i.e. (docker run --rm name), the spring boot app is started successfully.
When I try to access the webservices through compute engine instance external ip, it is not working.
I went through a different question, and found that I should try using the sudo wget http://localhost command on the instance cli first and if it is good then everything should be good. But I am getting a connection refused message on 127.0.0.1:80.
I also tried the command to open port from Container optimized OS, I.E.
sudo iptables -w -A INPUT -p tcp --dport 80 -j ACCEPT , nothing is working.
The default port for Spring Boot is 8080 and not 80.
Run this command inside the instance container to see what ports are in LISTENING state:
sudo netstat -tulpn | grep LISTEN
You can redirect port 80 to port 8080 with this command:
sudo iptables -t nat -I PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080
Note: This iptables command only redirects port 80 to 8080 on network interfaces. This has no effect for localhost or 127.0.0.1.
For Google Compute Engine instances you do not need to enable ports using iptables. This is done via Google VPC firewall rules. You can use both but make sure you understand exactly what you are configuring and the side effects.
Note: Your Spring Boot application needs to listen on 0.0.0.0 and not 127.0.0.1 nor localhost. The last two are internal only addresses. 0.0.0.0 means listen on all network interfaces.
Note: Do not use sudo in front of wget. This is not necessary.
First, confirm what port your springboot application uses - if it's 8080 or 80. This depends on what you have configured inside application.properties file. This port is referred to as ContainerPort in below steps.
Execute docker run <image-name>:<tag>. This will run the image and show container logs on the console. If there is something wrong with your spring-boot app, the logs will show that and the container will shutdown. Press Ctrl+C to stop the container and return to shell.
If there is no error in step 1 run docker run -d -p<HostPort>:<ContainerPort> <image-name>:<tag>. Here HostPort is any free port in your GCP host VM and ContainerPort is the port used by your spring boot application within the container. Option d starts your container in detached mode.
Run docker ps and make sure that the container started in step 2 is running. It may not run if there is an error - for example if the HostPort you specified is already in use.
If step 3 shows that the container is running, execute curl http://localhost:<HostPort>/<End-Point-Path>. Here End-Point-Path is a valid path to a working endpoint within the container. If the endpoint is correct you should see expected result from the spring-boot app in the console.
Navigate to Google Cloud Console -> VPC network -> Firewall rules and add a firewall rule to open HostPort on your GCP VM.
Access your endpoint via the VM's external IP with URL - http://<VM-External-IP>:<HostPort>/<End-Point-Path>
Unless there is an application issue with your spring-boot app these steps should get you going.
I was able to build the correct solution by your help (John Hanley and Cyac).
I am combining both solutions in order to help the next person facing this.
As told by John, by default Spring boot uses port 8080, not 80 and as specified by Cyac you need to specify the port as 80 explicitly in application.properties file using
server.port=80
Make sure you expose the port 80 in docker image
On GCP Contaier optimized OS make sure you have allowed traffic for HTTP and HTTPs
Run command:
sudo iptables -w -A INPUT -p tcp --dport 80 -j ACCEPT
Run docker using:
docker run -p 80:80 SPRING_IMAGE.
Where SPRING_IMAGE is the name of the docker image with spring boot build.
Test by using curl http://localhost/ENDPOINT_NAME , e.g. http://localhost/shops/all
I have a Windows Server 2016 TP5 machine that I use as a container host.
I have a Windows Container running that I manage with Docker. Inside this container I have an Apache httpd running on port 88.
The port mapping when I start the container is: 0.0.0.0:80->88/tcp, so I map port 80 of my container host to port 88 of the container.
This is the output from docker inspect: http://pastebin.com/AVem1eGV
I can now reach the Apache http start page from any other computer in the network through the DNS or IP.
In my case:
http://10.10.1.162/
http://documents.test2016-3.company.com/
But the same does not work when I try to call the same from the host system itself or from inside the container. So, on the host system, I try to access the same URL via browser or wget, and getting:
C:\> wget -UseBasicParsing http://documents.test2016-3.company.com/
wget : Unable to connect to the remote server
in both cases.
But I can ping the host from both the host itself as well as the container.
From the host:
C:\>ping test2016-3.company.com
Ping wird ausgeführt für TEST2016-3.company.com [fe80::847a:1430:8a10:b120%4] mit 32 Bytes Daten:
From the container:
PS C:\> ping documents.test2016-3.company.com
Pinging documents.test2016-3.company.com [10.10.1.162] with 32 bytes of data:
which seems to be able to resolve the name just fine.
What does work though is to call the Apache default page via the container hostname (which is win-de6u4068naf) and its running port directly (not through the port mapping), both from the host as well as inside the container:
http://win-de6u4068naf:88/
Just going the route through the container host hostname and mapped port from the host or container itself does not work properly!
Firewall rules allow everything on port 80 from any remote address or to port 80 (=inbound and outbound rules are both set to "allow" for "any").
I know that Microsoft/Docker changed the networking code base of the container/docker support from Windows Server 2016 TP4 to TP5. Not sure if that's related, or whether this is a bug or I'm having something not configured correctly yet.
I made a test and left Docker/Container out of the picture above and installed a plain Apache httpd itself on the container host system on port 80 (and no Docker running at all) just to check whether such setup works or not, in order to be sure that it is actually somehow Docker/Container related and not a problem with my network/host configuration in general. And this works fine, I can reach the Apache from outside as well as from the host itself, thus it must be a Docker/Container related problem.
Environment:
Windows Server 2016 TP5
Docker version 1.12.0-dev, build 2b97201
Got a reply on Microsoft's Github:
https://github.com/Microsoft/Virtualization-Documentation/issues/253#issuecomment-217975932
This is a known limitation in our Windows NAT implementation (WinNAT)
that you cannot access the external port in a static port mapping
directly from the container (NAT) host.
There is a related post here: Port mapping in Docker on Mac OSX installed with Docker Toolbox
but it didn't work for me
Get ports for container
docker port 485186e65a5e
8080/tcp -> 0.0.0.0:33360
8088/tcp -> 0.0.0.0:33359
19888/tcp -> 0.0.0.0:33358
50070/tcp -> 0.0.0.0:33357
50075/tcp -> 0.0.0.0:33356
8042/tcp -> 0.0.0.0:33361
Check that someone listens to ports in container
bash-4.1# netstat -alnpt | grep 19888
tcp 0 0 127.0.0.1:19888 0.0.0.0:* LISTEN 1094/java
Do wget in container
bash-4.1# wget 127.0.0.1:19888
--2016-04-11 14:16:54-- http://127.0.0.1:19888/
Connecting to 127.0.0.1:19888... connected.
HTTP request sent, awaiting response... 302 Found
Location: http://127.0.0.1:19888/jobhistory [following]
--2016-04-11 14:16:54-- http://127.0.0.1:19888/jobhistory
Reusing existing connection to 127.0.0.1:19888.
HTTP request sent, awaiting response... 200 OK
Length: 6763 (6.6K) [text/html]
Saving to: `index.html'
100%[================================================================================================================================================================================>] 6,763 --.-K/s in 0s
2016-04-11 14:16:54 (182 MB/s) - `index.html' saved [6763/6763]
Try to access forwarded port from host, no luck... :(((
$docker-machine ip default
192.168.99.100
$ wget 192.168.99.100:33358
--2016-04-11 16:18:04-- http://192.168.99.100:33358/
Connecting to 192.168.99.100:33358... failed: Connection refused.
What do I do wrong?
Omg, desired service started on 127.0.0.1 in container, that is why it wasn't visible from outside world. I've modified service config to start on 0.0.0.0 and now I can access forwarded container port
I had the same problem and was able to fix it by specifying the host that the server within the container uses.
NOTE: when using host below, it means a web server host. When I use host-machine, I mean the main operating system I'm using, (i.e. not a container or a web server, just my laptop as a machine)
The Problem
Running web servers on the container like webpack-dev-server and http-server automatically run the app using a host of http://localhost. Typically you will see that in the output when you start the server. Something like :
Project is running at http://localhost:8080
or
Server available at http://127.0.0.1:8080
On most machines, localhost and 127.0.0.1 are the same thing. This host is not publicly viewable. As a result, your host machine can't see anything, even though it's looking in the right place.
Solution
You should specify a public host when you run the server inside your container.
webpack-dev-server --port 8080 --host 0.0.0.0
or
http-server -p 8080 -a 0.0.0.0
Because the 0.0.0.0 address is viewable to any outside machine, you should be able to see your app working as expected from your host machine.
NOTE: This works for any server, like Python's SimpleHTTPServer, etc. Just look up how to change the host for your chosen server in the documentation
Resources/Nods
(how to run webpack-dev-erver with a publicly accessible host)[How to make the webpack dev server run on port 80 and on 0.0.0.0 to make it publicly accessible?
I'm using Boot2Docker to manage Docker containers in Windows and I have a container running an IBM Liberty server (I guess is the same for any other server), I can access the server home screen in the host machine using only the ip (which I get using the command boot2docker ip), but if I try to access the server using the https port, like this xx.xx.xx.xx:9443 the connection fails.
I tried forwarding the port in VirtualBox like this:
And then access the server using the ports 1000 or 1001, but it fails too.
Am I missing something?
BTW, I'm using default NAT connection.
https uses port 443 (not 9443) by default.
Make both "Host Port" and "Guest Port" 443 and try again.