I have some docker container running on a P2 instance.
In the past I run tmux in the P2 instance a run a docker container inside.
Afterwards I used
docker exec -it
to get into the running docker container.
I would like to avoid the above and be able to run tmux inside an existing container. hitting
tmux new -s <some name>
Doesn't do anything.
I assume that you want to connect to a docker container running remotely via tmux. In order to do this, you will have to run an ssh server within the container and attach to the tmux session using ssh. For example:
Create the container image with ssh and tmux installed. The Dockerfile might look like this:
FROM ubuntu:latest
RUN apt-get update && \
apt install -y tmux && \
apt install -y openssh-server && \
service ssh start && \
tmux new -s mysesh
EXPOSE 22/tcp
Run the container, and port forward the ssh port:
docker run -it -d -p 8654:22 <image name>
Attach to the tmux session:
ssh user#<hostname> -p 8654 -t "tmux a -t mysesh"
Note: tmux sessions are user specific, so ensure that the user exists in the container, and that the tmux session is started as the user within the container.
If tmux is already running in the container, it's as simple as docker attach container_name. (Docs.)
tmux might not be available in docker image, you can install it once you're attached to the docker container.
sudo apt install tmux
Then you should be able to execute
tmux new -s <some name>
Tried this on a P3 machine worked fine.
Reference: https://linuxize.com/post/getting-started-with-tmux/
Related
I have created a docker container that runs a command line tool. The container is supposed to be interactive. Am I somehow able to specify in the Dockerfile that the container is always started in interactive mode?
For reference this is the dockerfile:
FROM ubuntu:latest
RUN apt-get update && apt-get -y install curl
RUN mkdir adr-tools && \
cd adr-tools && \
curl -L https://github.com/npryce/adr-tools/archive/2.2.0.tar.gz --output adr-tools.tar.gz && \
tar -xvzf adr-tools.tar.gz && \
cp */src/* /usr/bin && \
rm -rf adr-tools
CMD ["/bin/bash"]
EDIT:
I know of the -it options for the run command. I'm explicitly asking for a way to do this in the docker file.
EDIT2:
This is not a duplicate of Interactive command in Dockerfile since my question addresses an issue with how arguments specified to docker run can be avoided in favor of specifying them in the Dockerfile whereas the supposed duplicate addresses an issue of interactive input during the build of the image by docker itself.
Many of the docker run options can only be specified at the command line or via higher-level wrappers (shell scripts, Docker Compose, Kubernetes, &c.). Along with port mappings and network settings, the “interactive” and “tty” options can only be set at run time, and you can’t force these in the Dockerfile.
You can use the docker run command.
docker build -t curly .
docker run -it curly curl https://stackoverflow.com
The convention is:
docker run -it IMAGE_NAME [COMMAND] [ARG...]
Where [COMMAND] is curl and [ARG...] are the curl arguments, which is https://stackoverflow.com in my example.
-i enables interactive process mode. You can't specify this in the Dockerfile.
-t allocates a pseudo-TTY for the container.
Are you looking for the -it option?
From the Docker documentation:
For interactive processes (like a shell), you must use -i -t together
in order to allocate a tty for the container process.
So, for example you can run it like:
docker run -it IMAGE_NAME [COMMAND] [ARG...]
Actually, in Ubuntu, I am running Apache Server in the background.
But for you, Try with below command and you should be able to go inside docker container.
docker exec -i -t your_container_name bash
I've used docker run -it to launch containers interactively and docker run -d to start them in background. These two options seemed exclusive. However, now I've noticed that docker run -dit (or docker run -itd) is quite common. So what is the difference? When -it is really needed together with -d?
Yes, sometimes, it's necessary to include -it even you -d
When the ENTRYPOINT is bash or sh
docker run -d ubuntu:14.04 will immediately stop, cause bash can't find any pseudo terminal to be allocated. You have to specify -it so that bash or sh can be allocated to a pseudo terminal.
docker run -dit ubuntu:14.04
If you want to use nano or vim with any container in the future, you have to specify -it when the image starts. Otherwise you'll get error. For example,
docker run --name mongodb -d mongo
docker exec -it mongodb bash
apt-get update
apt-get install nano
nano somefile
It will throw an error
Error opening terminal: unknown.
I want to install docker inside a running docker container.
docker run -it centos:centos7
My base container is using centos, I can login to running container using docker exec. But when I try to install docker inside it using yum install -y docker it installs.
But somehow I can't start the docker service with docker -d &, it gives me error as:
INFO[0000] Option DefaultNetwork: bridge
WARN[0000] Running modprobe bridge nf_nat br_netfilter failed with message: , error: exit status 1
FATA[0000] Error starting daemon: Error initializing network controller: Error initializing bridge driver: Setup IP forwarding failed: open /proc/sys/net/ipv4/ip_forward: read-only file system
Is there a way I can install docker inside docker container or build image already having running docker? I have already seen these examples but none works for me.
The output of uname -r on the host machine:
[fedora# ~]$ uname -r
4.2.6-200.fc22.x86_64
Any help would be appreciated.
Thanks in advance
Update
Thanks to https://stackoverflow.com/a/38016704/372019 I want to show another approach.
Instead of mounting the host's docker binary, you should copy or install a container specific release of the docker binary. Since you're only using it in a client mode, you won't need to install it as a system service. You still need to mount the Docker socket into the container so that you can easily communicate with the host's Docker engine.
Assuming that you got a base image with a working Docker binary (e.g. the official docker image), the example now looks like this:
docker run\
-v /var/run/docker.sock:/var/run/docker.sock\
docker:1.12 docker info
Without actually answering your question I'd suggest you to read Using Docker-in-Docker for your CI or testing environment? Think twice.
It explains why running docker-in-docker should be replaced with a setup where Docker containers run as siblings of the "outer" or "base" container. The article also links to the original https://github.com/jpetazzo/dind project where you can find working examples how to run Docker in Docker - in case you still want to have docker-in-docker.
An example how to enable a container to access the host's Docker daemon look like this:
docker run\
-v /var/run/docker.sock:/var/run/docker.sock\
-v /usr/bin/docker:/usr/bin/docker\
busybox:latest /usr/bin/docker info
If you are on Mac with Docker toolbox.
The below command WON’T WORK
docker run\
-v /var/run/docker.sock:/var/run/docker.sock\
-v /usr/bin/docker:/usr/bin/docker\
busybox:latest /usr/bin/docker info
Because /var/run/docker.sock will not be on your OSX filesystem
the Docker daemon is running inside the boot2docker VM - and that's where the unix socket is.
So you have to run the container from boot2docker VM
$ docker-machine ssh default
$ docker run\
-v /var/run/docker.sock:/var/run/docker.sock\
-v $(which docker):/usr/bin/docker\
busybox:latest /usr/bin/docker info
$ exit
This looks like Docker-in-Docker, feels like Docker-in-Docker, but it’s not Docker-in-Docker, when this container will create more containers, those containers will be created in the top-level Docker.
You need the --privileged parameter.
By default, Docker containers are “unprivileged” and cannot, for
example, run a Docker daemon inside a Docker container.
Source
Run your base image with the command docker run --privileged -it centos:centos7 bash. Then you may install and run another docker container inside that container.
I`ve a similar problems in my vms.
I`ve solve the problem with change the storage file system from image to vfs(in daemon.json file)
like the image bellow
For image works first create a base image, in my case with centos7
FROM centos:7
ENV container docker
RUN (cd /lib/systemd/system/sysinit.target.wants/; for i in *; do [ $i == \
systemd-tmpfiles-setup.service ] || rm -f $i; done); \
rm -f /lib/systemd/system/multi-user.target.wants/*;\
rm -f /etc/systemd/system/*.wants/*;\
rm -f /lib/systemd/system/local-fs.target.wants/*; \
rm -f /lib/systemd/system/sockets.target.wants/*udev*; \
rm -f /lib/systemd/system/sockets.target.wants/*initctl*; \
rm -f /lib/systemd/system/basic.target.wants/*;\
rm -f /lib/systemd/system/anaconda.target.wants/*;
VOLUME [ "/sys/fs/cgroup" ]
CMD ["/usr/sbin/init"]
with this image builded (in my case i called local/c7-systemd) create a second image, installing docker and moving daemon.json to inside.
FROM local/c7-systemd
RUN yum install -y yum-utils
RUN yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
RUN yum install -y docker-ce docker-ce-cli containerd.io
RUN curl -L "https://github.com/docker/compose/releases/download/1.28.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
RUN chmod +x /usr/local/bin/docker-compose
RUN ln -s /usr/local/bin/docker-compose /usr/bin/docker-compose
COPY daemon.json /etc/docker/daemon.json
RUN yum install -y nano
RUN systemctl enable docker
EXPOSE 80
EXPOSE 8080
EXPOSE 8161
EXPOSE 6379
EXPOSE 8761
CMD ["/usr/sbin/init"]
enjoy!
When I try to run chromium inside a docker container I see the following error: Gtk: cannot open display: :0
Dockerfile: (based on https://registry.hub.docker.com/u/jess/chromium/dockerfile)
FROM debian:jessie
# Install Chromium
RUN sed -i.bak 's/jessie main/jessie main contrib non-free/g' /etc/apt/sources.list && \
apt-get update && apt-get install -y \
chromium \
chromium-l10n \
libcanberra-gtk-module \
libexif-dev \
libpango1.0-0 \
libv4l-0 \
pepperflashplugin-nonfree \
--no-install-recommends && \
mkdir -p /etc/chromium.d/
# Autorun x11vnc
CMD ["/usr/bin/chromium", "--no-sandbox", "--user-data-dir=/data"]
build and run:
docker build -t chromium
docker run -e DISPLAY=$DISPLAY -v /tmp/.X11-unix:/tmp/.X11-unix --privileged chromium
and the error:
[1:1:0202/085603:ERROR:browser_main_loop.cc(164)] Running without the SUID sandbox! See https://code.google.com/p/chromium/wiki/LinuxSUIDSandboxDevelopment for more information on developing with the sandbox on.
No protocol specified
[1:1:0202/085603:ERROR:browser_main_loop.cc(210)] Gtk: cannot open display: :0
i don't know much about chromium, but, I did work with X way back when :-) When you tell an X client to connect to :0, what you are saying is connect to port 6000 (or whatever your X server runs on) + 0, or port 6000 in this case. In fact, DISPLAY is IP:PORT (with the +6000 as mentioned above). The X server is running on your host, so, if you set:
DISPLAY=your_host_ip:0
that might work. However, X servers did not allow connections from just any old client, so, you will need to open up your X server. on your host, run
xhost +
before running the docker container. All of this is assuming you can run chromium on your host (that is, an X server exists on your host).
Try
xhost local:root
This solve mine, I am on Debian Jessie. https://github.com/jfrazelle/dockerfiles/issues/4
Adding as reference (see real answer from greg)
In your Linux host add
xhost +"local:docker#"
In Docker image add
RUN apt-get update
RUN apt-get install -qqy x11-apps
and then run
sudo docker run \
--rm \ # delete container when bash exits
-it \ # connect TTY
--privileged \
--env DISPLAY=unix$DISPLAY \ # export DISPLAY env variable for X server
-v $XAUTH:/root/.Xauthority \ # provide authority information to X server
-v /tmp/.X11-unix:/tmp/.X11-unix \ # mount the X11 socket
-v /home/alex/coding:/coding \
alexcpn/nvidia-cuda-grpc:1.0 bash
Inside the container -check a sample command
xclock
For Ubuntu 20.04, changing DISPLAY=:0 to DISPLAY=$DISPLAY fixed it for me, my local env had $DISPLAY set to :1:
docker run --rm -ti --net=host -e DISPLAY=$DISPLAY fr3nd/xeyes
So, I also had a requirement to open a graphical application within my docker container. So, these are the steps that worked for my environment.(Docker version: 19.03.12 , Container OS: Ubuntu 18.04).
Before running the container, make the host's X server accept connections from any client by running this command: xhost +. This is a very non-restrictive way to connect to the host's X server, and you can restrict as per the other answers given. Then, run the container with the --network=host option (E.g: docker run --network=host <my image name>). Once container is up, log in to its shell, and launch your app with DISPLAY=:0 (E.g: DISPLAY=:0 <my graphical app>)
I got it to work on a Windows host but not on my Linux Mint (Ubuntu) host. The reason was that I was using Docker Desktop on Linux, which uses a VM under the hood.
Solution: Shut down Docker Desktop and install Docker Engine. Other than that, also do as in the other answers.
What is needed is an alias for your docker-hostname to the outer hostname. When using a DISPLAY starting with just a : it means localhost. Basically, your hostname inside docker needs to resolve via /etc/hosts to the same name as the outer host - because that is the name that is stored in .Xauthority
I found this script to autoget ip of your pc:
FOR /F "tokens=4 delims= " %%i in ('route print ^| find " 0.0.0.0"') do set localIp=%%i
Create a bat file and put in this bat this:
FOR /F "tokens=4 delims= " %%i in ('route print ^| find " 0.0.0.0"') do set
localIp=%%i
docker run -ti -v /tmp/.X11-unix -v /tmp/.docker.xauth -e
XAUTHORITY=/tmp/.docker.xauth --net=host -e DISPLAY=%localIp%:0.0 your-container
I am having a weird problem.
I am not able to ssh to docker container having ip address 172.17.0.61.
I am getting following error:
$ ssh 172.17.0.61
ssh: connect to host 172.17.0.61 port 22: Connection refused
My Dockerfile does contain openssh-server installation step:
RUN apt-get -y install curl runit openssh-server
And also step to start ssh:
RUN service ssh start
What could be the issue?
When I enter into container using nsenter and start ssh service then I am able to ssh. But while creating container ssh-server doesn't seems to start.
What should I do?
When building a Dockerfile you would create an image. But you can't create an image with an already running ssh daemon or any running service else. First if you create a running container out of the image you can start services inside. E.g. by appending the start instruction to the docker run command:
sudo docker run -d mysshserver service ssh start
You can define a default command for your docker image with CMD. Here is an example Dockerfile:
FROM ubuntu:14.04.1
MAINTAINER Thomas Steinbach
EXPOSE 22
RUN apt-get install -y openssh-server
CMD service ssh start && while true; do sleep 3000; done
You can build an run this image with the following two commands:
sudo docker build -t sshtest .
sudo docker run -d -P --name ssht sshtest
Now you can connect to this container via ssh. Note that in the example Dockerfile no user and no login was created. This image is just for example and you can start an ssh connection to it, but not login.
In my opinion there is a better approach:
Dockerfile
FROM ubuntu:14.04.1
EXPOSE 22
COPY docker-entrypoint.sh /docker-entrypoint.sh
RUN chmod +x /docker-entrypoint.sh
RUN apt-get install -y openssh-server
ENTRYPOINT ["sh", "/docker-entrypoint.sh"]
# THIS PART WILL BE REPLACED IF YOU PASS SOME OTHER COMMAND TO docker RUN
CMD while true; do echo "default arg" && sleep 1; done
docker-entrypoint.sh
#!/bin/bash
service ssh restart
exec "$#"
Build command
docker build -t sshtest .
The benefit of this approach is that your ssh daemon will always start when you use docker run, but you can also specify optional arguments e.g.:
docker run sshtest will print default arg every 1 second
whether docker run sshtest sh -c 'while true; do echo "passed arg" && sleep 3; done' will print passed arg every 3 seconds
I had the same problem.
Luckily I could solve it by checking kenorb answer and adapting it to my Dockerfile:
https://stackoverflow.com/a/61738823/4058295
It's worth a try :)