I'm new to docker and I try to find out how and if it's possible to attach the docker client to a host with a docker engine. My docker-engine runs on centOS in a virtual machine. Now I try to install a docker-client on my laptop to connect the client to the VM with the docker engine. Is there any possibility to do that?
Thanks for your answers!
you can use DOCKER_HOST environment variable and set it to the remote machine IP and port.
something like this -
export DOCKER_HOST="tcp://192.168.99.100:2376"
type docker-machine env to see if the environment is set correctly
yes, this is possible. you need to set the environment variables in the docker client to specify which host to connect to:
DOCKER_HOST=tcp://192.168.99.100:2376
DOCKER_TLS_VERIFY=1
DOCKER_CERT_PATH=<path to certificates>
(2375 is the insecure port and 2376 uses TLS). in order to use the secure connection, you need to have the certificates on the client machine.
this is assuming the docker daemon on the host machine has been set up to listen on a tcp socket (instead of named pipe)
Related
I have a Windows 10 Home machine (local machine) where I have installed Docker Toolbox that runs docker inside a VM. IP (192.168.0.6)
Also, there is another Windows 10 Pro machine (remote machine) that has Docker Desktop installed. IP (192.168.0.13). In the Docker Desktop setting, I have enabled "Expose daemon on tcp://localhost:2375 without TLS". At this point, I do not care about the TLS part since both the machines are on the local network. In the firewall setting, I have accepted inbound connections from port 2375.
Now I would like to run docker-compose from a local machine that connects and runs docker on the remote machine. To test connection, the command used on local machine is
docker -H tcp://192.168.0.13:2375 version
The response is
Cannot connect to the Docker daemon at tcp://192.168.0.13:2375. Is the docker daemon running?
I see that it calls https://192.168.0.13:2375/v1.40/info and not http://192.168.0.13:2375.
And in my remote machine, if I enter http://localhost:2375/v1.40/info I get a response but there is no response when I run by providing IP like http://192.168.0.13:2375/v1.40/info
I assume your docker daemon is only listening on localhost or 127.0.0.1.
You try to connect from another machine which connects to your machine with you internal network ip 192.168.0.13.
This means you need to configure your docker daemon to listen to:
192.168.0.13 = only network internal
tcp://192.168.0.13:2375
0.0.0.0 = all ip addresses
tcp://0.0.0.0:2375
In Windows you need to create a Docker-Daemon config file in:
C:\ProgramData\docker\config\daemon.json
with following content:
{
"hosts": ["tcp://0.0.0.0:2376"] # IP Address for container host
}
You can probably define a Subnet but i am not sure about this.
This is because the VM network interface is only binded to your localhost.
Try forwarding the port. From powershell or command prompt with admin privileges:
netsh interface portproxy add v4tov4 listenport=2375 listenaddress=192.168.0.13 connectaddress=127.0.0.1 connectport=2375
I am looking for a way to connect to my host machine in a Docker Container (in my case, access to a specific port for using a proxy in the application container).
I tried network_mode: "host" (or docker run --network="host"), it worked in case of accessing to local machine but caused some other problems which were related to changing network driver to host:
SQLSTATE[HY000] [2002] php_network_getaddresses: getaddrinfo failed: Name or service not known.
Also I can not use ifconfig to define network alias since I'm using Ubuntu 18.04.
What should I do?
UPDATE: Since the docker-host (https://github.com/qoomon/docker-host) image is published in the last few months, you can use that without any manual configuration. Easy peasy!
After struggling for a day, finally found the solution. It can be done by --add-host flag in docker run command or extra_hosts in a docker-compose.yml file with making an alias for Local (lo | 127.0.0.1 ) network interface.
So here are the instructions:
First, create an alias for lo interface. As you may know, ifconfig command does not exist on Ubuntu 18.04 so this is how we do it:
sudo ip addr add 192.168.0.20/24 dev lo label lo:1
Then, put this on you docker-compose.yml file:
extra_hosts:
- "otherhost:192.168.0.20"
If you are not using Docker Compose you can add a host to a container by --add-host flag. Something like
docker run container-name --add-host="otherhost:192.168.0.20"
Finally, when you're done with the above steps, restart your containers with docker-compose down && docker-compose up -d or docker-compose restart
Now you can log-in to your container (docker-compose exec container-name bash) and test it.
NOTE: Make sure your working port is open using telnet [interface-ip] [port] command.
You can use the extra_hosts in you docker-compose, which is what you discovered by yourself. I just wanted to add another way when you are working on your local environment.
In docker-for-mac and docker-for-windows, within a container the DNS name host.docker.internal resolves to an IP address allowing network access to the host.
Here's the related description, extracted from the documentation:
The host has a changing IP address (or none if you have no network access). From 18.03 onwards our recommendation is to connect to the special DNS name host.docker.internal, which resolves to the internal IP address used by the host. This is for development purpose and will not work in a production environment outside of Docker for Windows.
There's an open issue on github concerning the implementation of this feature for docker-for-linux.
Is is possible to do 'bridge' a X11 forward connection from a Docker to a Windows host by using the SSH connection?
On the Windows side I have Vagrant, VirtualBox and XMing installed. On the VirtualBox there is a CoreOS, serving the Docker images. What does work is adressing the display directly to the Windows machine by using the IP exposed by Vagrant (10.0.2.2):
docker run -e DISPLAY=10.0.2.2:0.0 someimage firefox
But this does not use the SSH tunnel, so it will only work in a local environment where the windows machine is reachable from the Docker container. From my understanding I would need to forward the display from within the Docker container to its outside, the CoreOS host and from there over to the SSH X11 entry-point.
In your docker image, expose the port for ssh and make sure x11 is enabled in the sshd of the image. Then you can ssh into that via x11 enabled client.
In order to ssh in from a remote machine, you need to add firewall permission for the port to which your Docker's port is mapped.
Bottom line: enable x11 in sshd of whatever your docker image is running on.
start docker with ssh port mapped to some port.
You're done here if only accessing from local Windows machine, else add firewall exception for the port to which you mapped docker's ssh daemon.
How to access or connect to a process running on docker on host A from a remote host B
consider a Host A with ip 192.168.0.3 which is running a application on docker on port 3999 .
If i want to access that application from remote machine with IP 192.168.0.4 in same subnet.
To be precise i am running Kafka producer on the server and i am trying to receive using Kafka-console-Consumer.
Use --net=host to run your container and it'll use the host's network stack, then you can connect to the application running inside container like it's running on host directly.
Port mapping, use option -p to map the port inside your container to a port of your host. e.g. docker run -d -p <container port>:<host port> <image>, then you can connect to <host>:<host port> to connect your application inside container
Docker's built-in multi-host network. In early releases the network driver is isolated from docker's core, you have to use 3rd party tools like flannel or weave for multi-host connection, but from release 1.9, it has been merged into docker. You can follow it's guide to set it up.
Hope this is helpful :-)
First you need to bind docker container's port to the Host A:
docker run -d -p 3999:3999 kafka-producer
Then you need to access Host A from Host B using IP:Port
192.168.0.3:3999
My service provider does not allow me to connect to docker on port 2376. Is there a flag for docker-machine to set up docker on host to listen on another port but 2376 so that commands like
docker-machine ls
OR
docker-machine env
work? Now they fail because after creation of docker on the host the daemon starts on port 2376 which is not accessible. Sure, I could manually change that port after creation but then the mentioned commands are not aware to connect to the docker daemon on that host on another port but 2376.
Is there a flag for docker-machine to set up docker on host to listen on another port but 2376
yes, use the -H or --host option of the docker daemon command. To make your Docker daemon listen on port 443 (which should be open all most firewalls), start your docker daemon with:
docker daemon -H tcp://0.0.0.0:443
If your docker host operating system is Debian or Ubuntu, you can set this in the /etc/default/docker file by adding the line DOCKER_OPTS="-H tcp://0.0.0.0:443".
If you are using RedHat or CentOS, add OPTIONS=-H tcp://0.0.0.0:443 to the /etc/sysconfig/docker file.
Using docker-machine
To install a Docker engine with a custom --host option, you would use docker machine with the --engine-opt option:
docker-machine create --engine-opt host=tcp://0.0.0.0:443 ...
Then when you use docker-machine env ... you will note that the DOCKER_HOST environment variable will still be set with the default port 2376, but now you can override it with 443 and it will work.
Unfortunately this won't allow docker-machine ls to work as the 2376 value for the docker engine port is hardcoded in docker-machine drivers. If you really want to get docker-machine ls to work for a different port, the easiest way would be to duplicate one of the docker-machine driver source file that you use and hardcode a different port ; then compile a new docker-machine binary with your new driver.
Let's say the IP address of the remote server is 11.22.33.44.
# create the docker engine using the generic Machine driver
docker-machine create --engine-opt host=tcp://0.0.0.0:443 --driver=generic --generic-ip-address=11.22.33.44 mytestengine
# prepare the environments so that docker client can connect on port 443
docker-machine env mytestengine
export DOCKER_HOST=tcp://11.22.33.44:443
# use docker client as usual
docker version