I have a running graylog2 docker container on a remote machine with ports 3000 and 12900 exposed (3000 routes to port 9000 within docker) and I can open graylog web UI on that port. So that works as expected. But for some reason I can't add logs from outside the container. Running this from the cli WORKS from INSIDE the container, but DOESN'T WORK from OUTSIDE:
curl -XPOST http://localhost:3000/gelf -p0 -d '{"short_message":"Hello there", "host":"example.org", "facility":"test", "_foo":"bar"}'
Running this command from outside the docker container I get:
{"type":"ApiError","message":"HTTP 404 Not Found"}
Edit: Found some information that this could possibly be solved by setting GRAYLOG_REST_TRANSPORT_URI to a public IP when running the docker container. Unfortunately when I start it like that, I run into another problem - can't start any inputs to receive logs. Bind address: 0.0.0.0 Port: 3000 It throws:
Request to start input 'project' failed. Check your Graylog logs for more information.
Edit2: Moved my testing environment to a local machine, to rule out possible server misconfigurations. Getting same errors and same problems.
Edit3: Decided to test out the graylog1 docker image and with that one everything actually works as expected right off the bat! So as a backup I could use an old version, but I'd rather avoid that if possible.
You have to start a GELF HTTP input to be able to receive GELF messages via HTTP.
The Graylog REST API does not provide this type of input.
Related
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.
I'm a bit confused. Trying to run both a HTTP server listening on port 8080 and a SSH server listening on port 22 inside a Docker container I managed to accomplish the latter but strangely not the former.
Here is what I want to achieve and how I tried it:
I want to access services running inside a Docker container using the IP address assigned to the container:
ssh user#172.17.0.2
curl http://172.17.0.2:8080
Note: I know this is not how you would configure a real web server but I want the container to mimic an embedded device which runs both services and which I don't have available all the time. (So it's really just a local non-production thing with no security requirements).
I didn't expect integrating the SSH server to be easy, but to my surprise I just installed and started it and had to do nothing else to be able to connect to the machine via ssh (no EXPOSE 22 or --publish).
Now I wanted to access the container via HTTP on port 8080 and fiddled with --publish and EXPOSE but only managed to make the HTTP server available through localhost/127.0.0.1 on the host. So now I can access it via
curl http://127.0.0.1:8080/
but I want to access both services via the same IP address which is NOT localhost (e.g. the address the container got randomly assigned is totally OK for me).
Unfortunately
curl http://172.17.0.2:8080/
waits until it times out every time I tied it.
I tried docker run together with -p 8080, -p 127.0.0.1:8080:8080, -p 172.17.0.2:8080:8080 and much more combinations, together or without EXPOSE 8080 in the Dockerfile but without success.
Why can I access the container via port 22 without having exposed anything?
And how do I make it accessible via the container's IP address?
Update: looks like I'm experiencing exactly what's described here.
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.
I'm currently testing an Ansible role using Molecule.
Basically, Molecule launches a container that is Ansible compliant and runs the role on it.
In order to test the container, Molecule also embed unit tests using Testinfra. The python unit tests are run from within the container so you can check the compliance of the role.
As I'm working on an Nginx based role, one of the unit tests is simply issuing a curl http://localhost:80
I do get the below error message in response:
curl: (7) Failed to connect to localhost port 80: Connection refused
When I:
launch a Vagrant machine
apply the role with Ansible
connect via vagrant ssh
issue a curl http://localhost command
nginx answers correctly.
Therefore, I believe that:
the role is working properly and Nginx is installed correctly
Docker has a different way to set-up the network. In a way, localhost and 127.0.0.1 are not the same anymore.
My questions are the following:
Am I correct?
Can this difference be overcome so the curl would work?
Docker containers start in their own network namespace by default. This namespace includes a separate loopback interface (127.0.0.1) that is distinct from the same interface on the host and any other containers. If you want to access an application from another container or via a published port on the host, you need to listen on all interfaces (0.0.0.0) rather than the loopback interface.
One other issue I often see is at some layer in the connection (the host, or inside of a container), the "localhost" name is mapped to the IPv6 value of ::1 in the /etc/host file, and somewhere in that connection only the IPv4 value is valid (either where the port was published, the application is listening, or IPv6 isn't enabled on the host or docker engine). Therefore, make sure to try connecting to the IPv4 address directly, 127.0.0.1, to eliminate any potential IPv6 issues.
Regarding the curl command and how to correct it, I cannot answer that without more details on how you are running the curl (is it in a separate container), how you are running your application, and how the two are joined on the network (did you create a new network in docker for your application and unit tests to run). The typical solution is to create a new network in docker, run both containers on that network, and connect via docker's included DNS to the container or service name of the destination, e.g. curl http://my_app/.
Edit: based on the comments, if your application and curl command are both running inside the same container, then curl http://127.0.0.1/ should work. There's no change I'm aware of needed with to curl to make it work inside of a container vs on a VM. The error you are seeing is likely from the application not starting and listening on the port as expected, possibly a race condition where the curl command is run too soon, or the base assumptions of how the tool works is incorrect. Start by changing the unit test to verify the application is up and running and listening on the port with commands like ps -ef and ss -lt.
it actually have nothing to do with the differences between Docker and Vagrant (i.e. containers vs VMs).
The testInfra code is actually run from outside the container / VM, hence the fact the subprocess.call(['curl', 'http://localhost']) is failing.
In order to run a command from the container / VM, I should use:
host.check_output('curl http://localhost')
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