Access docker remote API from container - docker

I'm trying to access Docker remote API from within a container because I need to start other containers.
The host address is 172.19.0.1, so I'm using http://172.19.0.1:2375/images/json to get the list of images (from host, http://localhost:2375/images/json works as expected.
The connection is refused, I guess because Docker (for Windows) listens on 127.0.0.1 and not on 0.0.0.0.
I've tried to change configuration (both from UI and daemon.json) adding the entry:
"hosts": ["tcp://0.0.0.0:2375"]
but the daemon fails to start. How can I access the api?

You can set DOCKER_OPTS in windows as below and try. In Windows, Docker runs inside a VM. So, you have to ssh into the VM and make the changes.
DOCKER_OPTS='-H tcp://0.0.0.0:4243 -H unix:///var/run/docker.sock'
Check if it works for you.
Update :- To ssh into the VM (assuming default is the VM name you have created using Docker toolbox), enter the following command in the Docker Quickstart Terminal,
docker-machine ssh default
You can find more details here.

You could link the host's /var/run/docker.sock within the container where you need it. This way, you don't expose the Docker Remote API via an open port.
Be aware that it does provide root-like access to docker.
-v /var/run/docker.sock:/var/run/docker.sock

You should use "tcp://host.docker.internal:2375" to connect to host machine from container. Please make sure that you can ping the "host.docker.internal" address
https://github.com/docker/for-win/issues/1976

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.

Nifi install using Docker - Can´t access the webserver

I'm new to both docker and Nifi, I found this command that installs via docker and used it on a virtual machine that I have in GCP but I would like to access this container via webserver. In docker ps this appears to me:
What command do I need to execute to gain access to the tool via port 8080?
The container has already exposed port 8080 on the host, as evidence by the output 0.0.0.0:8080->8080/tcp. You read that as {HOST_INTERFACE}:{HOST_PORT}->{CONTAINER_PORT}/{PROTOCOL}.
Navigate to http://SERVER_ADDRESS:8080/ (or maybe http://SERVER_ADDRESS:8080/nifi) using your web browser. You may need to modify the firewall rules applied to your VM to ensure that you can access that port from your local machine.

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

Unable to connect outside database from Docker container App

we have two machine…one is windows machine and another in Linux machine. My application is running under Docker Container at Linux machine. our data base is running at Windows machine.our application need to get data from windows machine DB.
As we have given proper data source detail like IP, username ,password in our application. it works when we do not use docker container but when we use docker container it do not work.
Can anyone help me out to get this solution that how we can connect outside DB from Docker enabled application as we are totally new guys in term of Docker.
Any help would be much appreciated.
Container's default network is "bridge",you should choose macvlan or host network.
method 1
docker run -d --net host image
this container will share your host IP address and will be able to access your database.
method 2
Use docker network create command to create a macvlan network,refrence here
then create your container by
docker run -d --net YOURNETWORK image
The container will have an IP address which is the same gateway with its host.
There are a lot of issues that could be affecting your container's ability to communicate with your database. In the future you should compose your question with as much detail as possible. To correctly answer this you will, at a minimum, need to include the following details:
Linux distribution name & version
Docker version
Output of docker inspect from the container
Linux firewall configuration
Network configuration
Is your Windows machine running on the same local network / subnet as your Linux machine? If so, please provide information about the subnet, as the default bridge set up by Docker may restrict access to local resources, whereas those over a wide area network would still be accessible.
You can try passing the --network=host option to your docker run command like so: docker run --network=host <image name>. Doing so eliminates the need to specify port mappings in your run command, as they are ignored when using the host's network.
Please edit your question and include the above requested details to get a complete answer.

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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