Often I come across this situation:
I have an existing docker container, running a certain service, usually set up from a Dockerfile from Github, etc., usually based on Ubuntu
I am able to run commands inside this container (with docker exec or by setting an entrypoint), including sh
Interactive commands like vi, nano, aptitude or mc don't work, because of the buggy terminal of Docker Toolbox - with errors ranging from defective arrow keys over garbled characters to plain crashes.
Now the question:
Can I run anything inside my container to connect to a machine with a proper terminal? For example I could SSH into the docker host, so maybe I can run something there that the container can connect to?
I tried mosh, but it seems the mosh client does not run a shell by itself, but instead tries to forward to sshd, which the container doesn't have.
Docker is used to create light weight containers that can run a service with as minimal resources as possible. In addition, docker does not limit what code, apps or utilities you would want to run. That being said, if you are trying to connect to the container as you would to other linux servers, via ssh, you would need to be sure that the docker instance contains and is running an ssh server such as openssh-server and that you expose the port, normally port 22, when you execute the 'docker run' command.
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Original Post
I have a Windows workstation with WSL2 and Docker installed that I am able to use for container based development in VS Code. I would like to be able to develop inside the containers on this system remotely. I am able to SSH directly into the WSL2 environment on the workstation and am able to start the docker daemon without logging directly into Windows by creating a Task to start the daemon automatically as described here: https://stackoverflow.com/a/59467740/10692741
However when I try to access Docker on the remote machine by following this guide: https://code.visualstudio.com/docs/remote/containers-advanced#_developing-inside-a-container-on-a-remote-docker-host, I get the following error:
error during connect: Get http://docker/v1.24/version: net/http: HTTP/1.x transport connection broken: malformed HTTP status code "\x00c\x00o\x00m\x00m\x00a\x00n\x00d\x00"
I have also tried connecting via a SSH tunnel as outlined here: https://code.visualstudio.com/docs/remote/troubleshooting#_using-an-ssh-tunnel-to-connect-to-a-remote-docker-host and am unable to connect to Docker as well.
Has anyone had success with a setup like this? Or is this not supported due to limitations with Docker on Windows, WSL2, and/or Windows OpenSSH implementation?
Update: 2021-01-21
When I SSH into the Windows machine remotely, I am able to see the docker containers in the VS Code extension. I am able to start them, stop them, and enter into them with the shell. However, when I try to attach VS Code I get same error shown above.
Things that may have possibly affected this over the past couple days:
Adding SSH keys on my local machine to the ssh-agent via ssh-add /my/key
Exposing Docker daemon on tcp://localhost:2375 without TLS on the remote Windows machine
Also I want to note that the I've tried using Windows, Mac, and Linux as the local machine. With Mac and Linux I am able to open a remote session into the Windows machine, but from the Windows local machine I am able to SSH into the remote Windows machine but cannot open a remote connection in VS Code for some reason.
Ok, I was able to get this working using the port/socket forwarding technique. For sake of clarity, I'll use:
local development workstation, local workstation, or just workstation to indicate the computer from which we wish to use VSCode to access Docker containers on ...
the remote Docker host, remote, or just Docker host
Sanity check -- Do you have Docker Desktop installed on both systems? On the local development workstation, you can skip the WSL2 integration, but you'll at least need the client tools, since the VSCode extension uses them.
Steps I took:
I already had Docker with WSL2 integration set up on my main system (which for the purposes of this exercise, became my remote Docker host), along with VSCode, so I knew everything was working there. It sounds like that was your starting point as well.
On another system on the same network (accessed with RDP to make it simple), I already had VSCode installed as well, with the Remote Development Extension Pack. I also have WSL on that system, but only a v1 instance there. Not that WSL on the workstation should be a factor at all for the purposes of this exercise.
I installed Docker Desktop for Windows on that local development workstation.
I also installed the Docker extension for VSCode, since I didn't yet have it on the local development workstation.
On the workstation, I was not yet set up to SSH from PowerShell into my WSL Ubuntu distro on the remote. From PowerShell on the workstation, I generated an ECDSA key (per this and other documents) and added the public key to my authorized_keys on the the remote.
On the workstation, I started the OpenSSH Authentication Service and added the newly created key to the agent (in PowerShell) with ssh-agent add ~\.ssh\id_ecdsa.
I logged out of the workstation and back in so that the path changes were picked up for the Docker desktop install.
I was then able to ssh from Powershell on the local to Ubuntu/WSL on the remote with the port forwarding. Since I'm using the Windows 10 OpenSSH server as a jumphost to my WSL SSH servers, my command looked slightly different (with a -o "ProxyCommand ... mainly), but overall the structure is the same as the one listed in the "SSH Tunnel" doc you linked in your question.
On the remote (manually, not through any integration from the local), I did a basic docker run -it --rm Ubuntu and left it open.
On the local, from PowerShell, I set the DOCKER_HOST environment variable via [System.Environment]::SetEnvironmentVariable("DOCKER_HOST","tcp://localhost:23750").
I was then able to see the remote container using docker ps on the local. I could also docker exec -it containername bash into it remotely.
Of course, the above two steps aren't needed in the long term for VSCode, they were just part of my process to make sure everything was up and running (since, as you might expect, I did have several points at which I failed during this process).
So with that working, it was a simple matter in VSCode to change the Docker extension's DOCKER_HOST setting to tcp://localhost:23750. And voila, I could see all images on the remote as well as attach to them from VSCode.
Other thing(s) to check
I'll add to this list if we find additional reasons why it might not be working, but for now:
You mention that you are starting the Docker Desktop daemon automatically at startup via Task Manager, but you don't mention anything about the WSL2 instance. However, since you are able to ssh into it, I assume you have a way to bring it up as well? My experience has been that, unless the owning user is logged in, WSL terminates any instances after a few seconds, even if a service is running. There's a workaround, I believe, that I can dust off if this is a problem.
I try to run docker in bash ubuntu on windows. But every time I get this message
"Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?". If i run it in powershell - it work. Can somebody help?
Connecting to the docker deamon requires some privilidges that you don't have when starting the bash terminal.
You can however use the docker command terminal which will allow you to interact with the docker deamon.
Found the solution on this post: https://blog.jayway.com/2017/04/19/running-docker-on-bash-on-windows/
Connect Docker on WSL to Docker on Windows
Running docker against an engine on a different machine is actually quite easy, as Docker can expose a TCP endpoint which the CLI can attach to.
This TCP endpoint is turned off by default; to activate it, right-click the Docker icon in your taskbar and choose Settings, and tick the box next to “Expose daemon on tcp://localhost:2375 without TLS”.
With that done, all we need to do is instruct the CLI under Bash to connect to the engine running under Windows instead of to the non-existing engine running under Bash, like this:
$ docker -H tcp://0.0.0.0:2375 images
REPOSITORY TAG IMAGE ID CREATED SIZE
There are two ways to make this permanent – either add an alias for the above command, or better yet, export an environment variable which instructs Docker where to find the host engine:
$ echo "export DOCKER_HOST='tcp://0.0.0.0:2375'" >> ~/.bashrc
$ source ~/.bashrc
Now, running docker commands from Bash works just like they’re supposed to.
$ docker run hello-world
Hello from Docker!This message shows that your installation appears to be working correctly.
I am running the latest Docker Toolbox, using latest Oracle VirtualBox, with Windows 7 as a host OS.
I am trying to enable non-TLS access to Docker remote API, so I could use Postman REST client running on Windows and hit docker API running on docker-machine in the VirtualBox. I found that if Docker configuration included -H tcp://0.0.0.0:2375, that would do the trick exposing the API on port 2375 of the docker machine, but for the life of me I can't find where this configuration is stored and can be changed.
I did docker-machine ssh from the Toolbox CLI, and then went and pocked around the /etc/init.d/docker file, but no changes to the file survive docker-machine restart.
I was able to find answer to this question for Ubuntu and OSX, but not for Windows.
#CarlosRafaelRamirez mentioned the right place, but I will add a few details and provide more detailed, step-by-step instructions, because Windows devs are often not fluent in Linux ecosystem.
Disclaimer: following steps make it possible to hit Docker Remote API from Windows host, but please keep in mind two things:
This should not be done in production as it makes Docker machine very not secure.
Current solution disables most of the docker-machine and all docker CLI functionality. docker-machine ssh remains operational, forcing one to SSH into docker machine to access docker commands.
Solution
Now, here are the steps necessary to switch Docker API to non-TLS port. (Docker machine name is assumed to be "default". If your machine name has a different name, you will need to specify it in the commands below.)
Start "Docker Quickstart Terminal". It starts Bash shell and is the place where all following commands will be run. Run docker-machine ip command and note the IP address of the docker host machine. Then do
docker-machine ssh
cd /var/lib/boot2docker
sudo vi profile This starts "vi" editor in elevated privileges mode required for editing "profile" file, where Docker host settings are. (If as a Windows user you are not familiar with vi, here's is super-basic crash course on it. When file is open in the vi, vi is not in editing mode. Press "i" to start edit mode. Now you can make changes. After you made all the changes, hit Esc and then ZZ to save changes and exit vi. If you need to exit vi without saving changes, after Esc please type :q! and hit Enter. ":" turns on vi's command mode, and "q!" command means exit without saving. Detailed vi command info is here.)
Using vi, change DOCKER_HOST to be DOCKER_HOST='-H tcp://0.0.0.0:2375', and set DOCKER_TLS=no. Save changes as described above.
exit to leave SSH session.
docker-machine restart
After doocker machine has restarted, your sould be able to hit docker API URL, like http://dokerMachineIp:2375/containers/json?all=1, and get valid JSON back.
This is the end of steps required to achieve the main goal.
However, if at this point you try to run docker-machine config or docker images, you will see an error message indicating that docker CLI client is trying to get to the Docker through the old port/TLS settings, which is understandable. What was not expected to me though, is that even after I followed all the Getting Started directions, and ran export DOCKER_HOST=tcp://192.168.99.101:2375 and export DOCKER_TLS_VERIFY=0, resulting in
$ env | grep DOCKER
DOCKER_HOST=tcp://192.168.99.101:2375
DOCKER_MACHINE_NAME=default
DOCKER_TLS_VERIFY=0
DOCKER_TOOLBOX_INSTALL_PATH=C:\Program Files\Docker Toolbox
DOCKER_CERT_PATH=C:\Users\USERNAME\.docker\machine\machines\default
the result was the same:
$ docker-machine env
Error checking TLS connection: Error checking and/or regenerating the certs: There was an error validating certificates for host
"192.168.99.101:2376"
If you see a problem with how I changed environment variables to point Docker CLI to the new Docker host address, please comment.
To work around this problem, use docker-machine ssh command and run your docker commands after that.
I encountered the same problem and thanks to #VladH made it working not changing any internal Docker profile properties. All you have to do is correctly define Windows local env variables (or configure maven plugin properties, if you use io.fabric8 docker-maven-plugin).
Note that 2375 port is used for non-TLS connections, and 2376 only for TLS connections.
DOCKER_HOST=tcp://192.168.99.100:2376
DOCKER_TLS_VERIFY=0
DOCKER_TOOLBOX_INSTALL_PATH=C:\Program Files\Docker Toolbox
DOCKER_CERT_PATH=C:\Users\USERNAME\.docker\machine\machines\default
I have to pull docker image from Docker Hub and start running multiple peers as containers.
now, I am manually opening terminal and executing my docker run command on downloaded image but I am planning to automate this process like if I/user want 2 peers to run then I should be able to provide IP Address and Port information to Docker run command and start these peers in different terminals without manual step.
After executing these commands I should be able to store these IP address and port numbers in a JSON file further transactions.
Could you please help me!!! Thanks!!
Got quick solution for the above problem.. Below is the command I have applied docker run -d IMAGE NAME /bin/bash above command runs the container in background process. Also, I am taking network credentials by applying docker inspect <Container Id>
I installed boot2docker as explained on the docker website. Here are some command runs to show that I have things installed correctly:
$$:~ kv$ boot2docker start
Waiting for VM and Docker daemon to start...
...................ooo
Started.
Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/ca.pem
Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/cert.pem
Writing /Users/kvantum/.boot2docker/certs/boot2docker-vm/key.pem
Your environment variables are already set correctly.
$$:~ kv$ docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
ubuntu 14.04 b39b81afc8ca 11 days ago 188.3 MB
hello-world latest e45a5af57b00 3 weeks ago 910 B
After this, I ran the following command:
docker run -t -i ubuntu:14.04 /bin/bash
Inside the container, I installed zeromq, and started a zeromq server on port 5555 using tcp.
My questions are following:
If I exit out of the container, will it save all the work I do inside it?
I have no idea how to connect to the server running on port 5555. I read something about exposing a port, but I am not sure how to go about doing that. I did an ifconfig inside the container, and tried to connect to the server from the host like this:
$$:~ kv$ ./zmq_client tcp://container_ip:5555
This did not work. Can someone please lists the steps I need to take in order to connect to the server running within the container.
For completion sake, I am providing the list of my environment variables:
TERM_PROGRAM=Apple_Terminal
TERM=xterm-256color
SHELL=/bin/bash
TMPDIR=/var/folders/km/5kbpdx4s7cg4rmyc6d5q9l9r0000gq/T/
DOCKER_HOST=tcp://192.168.109.103:2376
Apple_PubSub_Socket_Render=/tmp/launch-1tWMHJ/Render
TERM_PROGRAM_VERSION=326
OLDPWD=/Users
TERM_SESSION_ID=262CBC8B-0A74-4B70-9F28-D9FA51FF713C
USER=kv
SSH_AUTH_SOCK=/tmp/launch-ZTWNGL/Listeners
__CF_USER_TEXT_ENCODING=0x1F7:0:0
DOCKER_TLS_VERIFY=1
__CHECKFIX1436934=1
PATH=/usr/bin:/bin:/usr/sbin:/sbin:/usr/local/bin:/opt/X11/bin
PWD=/Users/kv
DOCKER_CERT_PATH=/Users/kv/.boot2docker/certs/boot2docker-vm
HOME=/Users/kv
SHLVL=1
LOGNAME=kv
LC_CTYPE=UTF-8
DISPLAY=/tmp/launch-rco9zt/org.macosforge.xquartz:0
_=/usr/bin/env
One last question I have is about code performance. So within my Mac OS X, I have a docker container running (which runs Ubuntu). If I run the application, like a zeromq based server inside the container, will it not be slower as compared to running it on Mac OS X directly. Please explain the benefits of using docker in such a scenario..
You should really do some more reading and research before turning to SO, then ask about anything you can't figure out. But:
No. If the container is "exited" you can restart it and your files will still be there, but once it is removed your files are gone. You can use docker commit to save them to an image, but the best bet is to use a Dockerfile.
docker run -p 5000:8000 image will expose port 8000 in the container as port 5000 on the host.
Yes, it will be slower due to the boot2docker VM. It would not be slower if you were running on a Linux host. The advantage is that zeromq is now running in an isolated container with all its dependencies.