How can I keep docker container running? - docker

I want to run multiple containers automatically and create something,
but some images, such as swarm, will automatically stop after run or start.
I already try like that
docker run -d swarm
docker run -d swarm /bin/bash tail -f /dev/null
docker run -itd swarm bash -c "while true; do sleep 1; done"
but 'docker ps' show nothing, and I tried to build Dockerfile by typing:
FROM swarm
ENTRYPOINT ["echo"]
and The image does not run with error message :
docker: Error response from daemon: invalid header field value "oci runtime error: container_linux.go:247: starting container process caused \"exec: \\\"echo\\\": executable file not found in $PATH\"\n".
I can't understand this error... How can I keep swarm container running..?
(Sorry,my English is not good))

using -d is recommended because you can run your container with just one command and you don’t need to detach terminal of container by hitting Ctrl + P + Q.
However, there is a problem with -d option. Your container immediately stops unless the commands are not running on foreground.
Docker requires your command to keep running in the foreground. Otherwise, it thinks that your applications stops and shutdown the container.
The problem is that some application does not run in the foreground.
In this situation, you can add tail -f /dev/null to your command.
By doing this, even if your main command runs in the background, your container doesn’t stop because tail is keep running in the foreground.
docker run -d swarm tail -f /dev/null
docker ps shows container
Now you can attach your container by using docker exec container_name command
or
docker run -d swarm command tail -f /dev/null

First of all you don't want to mix the -i and -d switches. Either you would like to run the container in interactive or detached mode. In your case in detached mode:
docker run -d swarm /bin/bash tail -f /dev/null
There are also no need to allocate a tty using the -t flag, since this only needs to be done in interactive mode.
You should have a look at the Docker run reference

Docker container does two type of task. One is to perform and exit & other is to run it in background.
To run docker container in background, there are few options.
Run using shell. docker run -it <image> /bin/bash
For continuously running container. docker run -d -p 8080:8080 <image>. Assuming image will expose port 8080 and in listening mode.

It's fine to to a tail on /dev/null, but why not make it do something useful?
The following command will reap orphan processes, so no zombie (defunct) precesses are left floating around. Also some init.d / restart scripts doesn't allow this.
exec sh -c 'while true ;do wait ;done'

You are right docker run -itd swarm ( Without give argument for container( bash -c "while true; do sleep 1; done" ) )works fine .If you pass argument for docker run it will run the command and terminates the container.If you want to run the container permanently first start the container with docker run -itd swarm and check if the container runs or not by docker ps now the container runs , if you want to execute any command in container use docker exec -itd container_name command Remember : Only use the command which not stop the container. bash -c "while true; do sleep 1; done this command will stop the container ( Because this is complete command if we execute in normal terminal it execute and terminate , this type of command also terminates the container ).
I Hope this Helps..

Basically this is the method , but your docker image is swarm so it is different and i don't know about swarm docker image and i am not using that .But after i research about that . First i run the docker swarm image it shows.,
After that i understand we run docker swarm image by using only five commands in picture like create, list manage, join, help . if we run swarm image without command like docker run -itd swarm it takes command as --help . Sorry, But i don't know what is the purpose of swarm image. For more usage check https://hub.docker.com/_/swarm/ .
The answer that i added docker run -itd image tail -f /dev/null is not for swarm image , it is for docker images like ubuntu,fedora, centos.
Just read the usage of swarm image and why it is used .
After if you have any issue post your issue in https://github.com/docker/swarm-library-image/issues
Thank You...

have a container running
docker run --rm -d --name=tmp ubuntu sleep infinity
example of requesting a command from the dorment container
docker exec tmp echo hello from container
notes:
--rm removes the container if it is stopped
-d runs the container in the background
--name=tmp name the container so you control how to denote it
ubuntu pushes a light image to exec your commands
sleep infinity keeps the container dorment

Related

Command docker start -a <Container ID> do nothing, "Ubuntu 20.04.02 LTS"

i'm trying to run the start command in docker after creating a container.
for example :
$ docker create busybox echo hi there
it gives me the id of that container like 4e59d0fe8584bb4dcaf44dbce100253b6767bf51546edc27f29f39f52ed57957
and when i try to start that container without any flags like: -a flag
it works, but it only gives me that id back again.
but when i try to show the output using the attach -a flag, actually nothing happened, even it didn't give me an error, simply the command still running without anything happened.
i also couldn't kill the command and stop the execution by Ctrl+c, so the only option i had to close the terminal
i tried to make the problem clear as possible as i can
You can run the image via this command:
docker run -it busybox
It goes you to shell environment and you have -i (interactive) -t (tty) terminal, which means you see the terminal.
The default CMD(PID1) for busybox image is sh, see this.
For docker create busybox echo hi there, the COMMAND becomes echo hi there. This means after container starts, it will first execute echo hi there, then as PID1 exit, the container exit too. If you use docker ps, you won't find your container, you could just find your exited container with docker ps -a.
So,
If you intend to run a one time task, then as the container finish its task, it's normal you could not enter into container anymore.
If you intend to run a daemon task, leave the container service there, you should choose a command which won't finish after run, then your container will still there.
For your case, to quick let you understand it, you could use next to have a quick understanding, use tail -f /dev/null to let the container not exit:
# docker create busybox sh -c "echo hi there; tail -f /dev/null"
840d7c972a96712e48c9aa391aa63638fb10e12307797e338157105bdfb6934e
root#shlava:~# docker start 840d7c972a96712e48c9aa391aa63638fb10e12307797e338157105bdfb6934e
840d7c972a96712e48c9aa391aa63638fb10e12307797e338157105bdfb6934e
root#shlava:~# docker logs 0ae2d689e63a8688213d1eaf285e555ba3d672b8953f0d2730a1897c9d648a26
hi there
root#shlava:~# docker exec -it 0ae2d689e63a8688213d1eaf285e555ba3d672b8953f0d2730a1897c9d648a26 /bin/sh
/ #

What is the meaning of running container?

'docker exec' can only used on running container, but what is the meaning of running container? Is that means the container should be computing something? or is the issue about the [command] which I define for the container? Why my TensorFlow container always be stopped status?
After I used 'docker run' to build a tensorflow container, the container stopped automatically. I need to restart it and then execute command on it. Why the container cannot be always in running since I build it?
docker run -it --runtime=nvidia tensorflow/tensorflow:latest-gpu-py3
It will then pops up a bash which I can use to control the container. But after I exit, the container stopped itself. Which means, I can only use docker ps -a to see my container but docker pscan not. I have to restart the container if I want to use my container again.
UPDATE1: If I want create a container like VM, I cannot use docker run with a temporal [command] like python ... The container will lose control permanently after the command finished. docker restart cannot start the container again. Hence, docker exec cannot apply on it. Instead, using bash or nothing as the [command] can create a container which can be restart, therefore, can be applied withdocker exec.
UPDATE2: docker run -d -it can create a running container (but the bash shell won't pops up, neither even with bash). Directly using docker exec -it container_name bash can take the control of the running container again, without docker restart. In this time, exiting bash shell will not stop the container.
A container is running when there is an active process running inside it.
When you are running this tensorflow container, it will exit due to there being no running process
If you were to run
docker run -it --runtime=nvidia tensorflow/tensorflow:latest-gpu-py3 bash
or
docker run -it --runtime=nvidia tensorflow/tensorflow:latest-gpu-py3 python <python script name>
then the container would run the bash/python script as a process and therefore remain up whilst that process is running
View running processes with:
docker ps
See all containers (including stopped/exited tasks) with:
docker ps -a
The difference between docker ps -a and docker ps is exactly what you are looking for:
From the documentation:
--all , -a Show all containers (default shows just running)
So
docker ps gives you only running container
docker ps -a also shows you the stopped ones
So probably, if you expect you container to be long running, (like it would for a web server), then indeed your container command could have an issue and is not keeping your container alive.
Also mind that, if you run your container with the options -ti, like you did, you get an interactive tty attached to it.
--tty , -t Allocate a pseudo-TTY
--interactive , -i Keep STDIN open even if not attached
That basically means that, as soon as you exit that interactive context, your container will shut down.
Running it in a detached mode, with the options -d, is maybe what you are looking for
docker run -d --runtime=nvidia tensorflow/tensorflow:latest-gpu-py3
Related documentation:
--detach , -d Run container in background and print container ID
https://docs.docker.com/engine/reference/commandline/run/

docker run in detached mode - basic question

I run it in detached mode with,
docker run -d busybox:1.24
But it does not show up in docker ps
what is the reason? Should not it be working?
Should i have to pass "running command" like sleep 1000?
EDIT: Seems like the container stops when there is nothing to run.
When you run docker ps, you will only see a list of containers that are running.
To see all containers, including ones that are stopped, created, exited, restarting etc, you should use docker ps -a.
The busybox container isn’t running anything. So it will just exit as soon as it starts.
If you do docker run -d busybox:1.24 sleep 10, then run docker ps, you will see the running container - until the sleep process exits (after 10 seconds). At which point, you’ll need to use docker ps -a again.
Depends on what the CMD directives says in your Dockerfile. If you dont run a script or program that is running continuous the the container will simple end right away.
To see the status of the container: -a shows even exited containers
docker ps -a
To see what happend when it ran
docker logs <container-id>
To run a cmd prompt
docker run -it <container-id> /bin/bash
To run in detached mode you need a script or command that will wait eg:
sleep infinite

Docker container will automatically stop after "docker run -d"

According to tutorial I read so far, use "docker run -d" will start a container from image, and the container will run in background. This is how it looks like, we can see we already have container id.
root#docker:/home/root# docker run -d centos
605e3928cdddb844526bab691af51d0c9262e0a1fc3d41de3f59be1a58e1bd1d
But if I ran "docker ps", nothing was returned.
So I tried "docker ps -a", I can see container already exited:
root#docker:/home/root# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
605e3928cddd centos:latest "/bin/bash" 31 minutes ago Exited (0) 31 minutes ago kickass_swartz
Anything I did wrong? How can I troubleshoot this issue?
The centos dockerfile has a default command bash.
That means, when run in background (-d), the shell exits immediately.
Update 2017
More recent versions of docker authorize to run a container both in detached mode and in foreground mode (-t, -i or -it)
In that case, you don't need any additional command and this is enough:
docker run -t -d centos
The bash will wait in the background.
That was initially reported in kalyani-chaudhari's answer and detailed in jersey bean's answer.
vonc#voncvb:~$ d ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
4a50fd9e9189 centos "/bin/bash" 8 seconds ago Up 2 seconds wonderful_wright
Note that for alpine, Marinos An reports in the comments:
docker run -t -d alpine/git does not keep the process up.
Had to do: docker run --entrypoint "/bin/sh" -it alpine/git
Original answer (2015)
As mentioned in this article:
Instead of running with docker run -i -t image your-command, using -d is recommended because you can run your container with just one command and you don’t need to detach terminal of container by hitting Ctrl + P + Q.
However, there is a problem with -d option. Your container immediately stops unless the commands keep running in foreground.
Docker requires your command to keep running in the foreground. Otherwise, it thinks that your applications stops and shutdown the container.
The problem is that some application does not run in the foreground. How can we make it easier?
In this situation, you can add tail -f /dev/null to your command.
By doing this, even if your main command runs in the background, your container doesn’t stop because tail is keep running in the foreground.
So this would work:
docker run -d centos tail -f /dev/null
Or in Dockerfile:
ENTRYPOINT ["tail"]
CMD ["-f","/dev/null"]
A docker ps would show the centos container still running.
From there, you can attach to it or detach from it (or docker exec some commands).
According to this answer, adding the -t flag will prevent the container from exiting when running in the background. You can then use docker exec -i -t <image> /bin/bash to get into a shell prompt.
docker run -t -d <image> <command>
It seems that the -t option isn't documented very well, though the help says that it "allocates a pseudo-TTY."
Background
A Docker container runs a process (the "command" or "entrypoint") that keeps it alive. The container will continue to run as long as the command continues to run.
In your case, the command (/bin/bash, by default, on centos:latest) is exiting immediately (as bash does when it's not connected to a terminal and has nothing to run).
Normally, when you run a container in daemon mode (with -d), the container is running some sort of daemon process (like httpd). In this case, as long as the httpd daemon is running, the container will remain alive.
What you appear to be trying to do is to keep the container alive without a daemon process running inside the container. This is somewhat strange (because the container isn't doing anything useful until you interact with it, perhaps with docker exec), but there are certain cases where it might make sense to do something like this.
(Did you mean to get to a bash prompt inside the container? That's easy! docker run -it centos:latest)
Solution
A simple way to keep a container alive in daemon mode indefinitely is to run sleep infinity as the container's command. This does not rely doing strange things like allocating a TTY in daemon mode. Although it does rely on doing strange things like using sleep as your primary command.
$ docker run -d centos:latest sleep infinity
$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d651c7a9e0ad centos:latest "sleep infinity" 2 seconds ago Up 2 seconds nervous_visvesvaraya
Alternative Solution
As indicated by cjsimon, the -t option allocates a "pseudo-tty". This tricks bash into continuing to run indefinitely because it thinks it is connected to an interactive TTY (even though you have no way to interact with that particular TTY if you don't pass -i). Anyway, this should do the trick too:
$ docker run -t -d centos:latest
Not 100% sure whether -t will produce other weird interactions; maybe leave a comment below if it does.
Hi this issue is because docker containers exit if there is no running application in the container.
-d
option is just to run a container in deamon mode.
So the trick to make your container continuously running is point to a shell file in docker which will keep your application running.You can try with a start.sh file
Eg: docker run -d centos sh /yourlocation/start.sh
This start.sh should point to a never ending application.
In case if you dont want any application to be running,you can install monit which will keep your docker container running.
Please let us know if these two cases worked for you to keep your container running.
All the best
You can accomplish what you want with either:
docker run -t -d <image-name>
or
docker run -i -d <image-name>
or
docker run -it -d <image-name>
The command parameter as suggested by other answers (i.e. tail -f /dev/null) is completely optional, and is NOT required to get your container to stay running in the background.
Also note the Docker documentation suggests that combining -i and -t options will cause it to behave like a shell.
See:
https://docs.docker.com/engine/reference/run/#foreground
I have this code snippet run from the ENTRYPOINT in my docker file:
while true
do
echo "Press [CTRL+C] to stop.."
sleep 1
done
Run the built docker image as:
docker run -td <image name>
Log in to the container shell:
docker exec -it <container id> /bin/bash
execute command as follows :
docker run -t -d <image-name>
if you want to specify port then command as below:
docker run -t -d -p <port-no> <image-name>
verify the running container using following command:
docker ps
Docker container exits if task inside is done, so if you want to keep it alive even if it does not have any job or already finished them, you can do docker run -di image. After you do docker container ls you will see it running.
Docker requires your command to keep running in the foreground. Otherwise, it thinks that your applications stops and shutdown the container.
So if your docker entry script is a background process like following:
/usr/local/bin/confd -interval=30 -backend etcd -node $CONFIG_CENTER &
The '&' makes the container stop and exit if there are no other foreground process triggered later.
So the solution is just remove the '&' or have another foreground CMD running after it, such as
tail -f server.log
If you are using CMD at the end of your Dockerfile, what you can do is adding the code at the end. This will only work if your docker is built on ubuntu, or any OS that can use bash.
&& /bin/bash
Briefly the end of your Dockerfile will look like something like this.
...
CMD ls && ... && /bin/bash
So if you have anything running automatically after you run your docker image, and when the task is complete the bash terminal will be active inside your docker. Thereby, you can enter you shell commands.
Maybe it is just me but on CentOS 7.3.1611 and Docker 1.12.6 but I ended up having to use a combination of the answers posted by #VonC & #Christopher Simon to get this working reliably. Nothing I did before this would stop the container from exiting after it ran CMD successfully. I am starting oracle-xe-11Gr2 and sshd.
Dockerfile
...
RUN ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key -N '' && systemctl enable sshd
...
CMD /etc/init.d/oracle-xe start && /sbin/sshd && tail -f /dev/null
Then adding -d -t and -i to run
docker run --shm-size=2g --name oracle-db -d -t -i -p 5022:22 -p 5080:8080 -p 1521:1521 centos-oracle:7.3.1611
Finally after hours of bashing my head against the wall
ssh -v root#127.0.0.1 -p 5022
...
root#127.0.0.1's password:
debug1: Authentication succeeded (password).
For whatever reason the above will exit after executing CMD if the tail -f is removed, or any of the -t -d -i options are omitted.
I had the same issue, just opening another terminal with a bash on it worked for me :
create container:
docker run -d mcr.microsoft.com/mssql/server:2019-CTP3.0-ubuntu
containerid=52bbc9b30557
start container:
docker start 52bbc9b30557
start bash to keep container running:
docker exec -it 52bbc9b30557 bash
start process you need:
docker exec -it 52bbc9b30557 /path_to_cool_your_app
Running docker with interactive mode might solve the issue.
Here is the example for running image with and without interactive mode
chaitra#RSK-IND-BLR-L06:~/dockers$ sudo docker run -d -t -i test_again1.0
b6b9a942a79b1243bada59db19c7999cfff52d0a8744542fa843c95354966a18
chaitra#RSK-IND-BLR-L06:~/dockers$ sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
chaitra#RSK-IND-BLR-L06:~/dockers$ sudo docker run -d -t -i test_again1.0 bash
c3d6a9529fd70c5b2dc2d7e90fe662d19c6dad8549e9c812fb2b7ce2105d7ff5
chaitra#RSK-IND-BLR-L06:~/dockers$ sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
c3d6a9529fd7 test_again1.0 "bash" 2 seconds ago Up 1 second awesome_haibt
You can simply use:
docker container run -d -it <container name or id> /bin/bash
I have explained it in the following post that has the same question.
How to retain docker alpine container after "exit" is used?
I was also facing the same problem but in a different manner. When I create the docker containers. it automatically stops the unused containers which are just running in the background. Sometimes it also stops the containers that are in the use.
In my situation, this is because of the permission of the docker.sock files it earlier has.
what you have to do is :-
Install docker again.(As i work on ubuntu i install it from here)
Run the command to change the permissions.
sudo chmod 666 /var/run/docker.sock
Install docker-compose (this is optional as I have compose file to create many containers together)
sudo curl -L "https://github.com/docker/compose/releases/download/1.26.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose
check for the version to ensure that I have the latest one and not get problem with some deprications.
Then I run the docker container build.
Argument order matters
Jersey Beans answer (all 3 examples) worked for me. After quite a bit of trial and error I realized that the order of the arguments matter.
Keeps the container running in the background:
docker run -t -d <image-name>
Keeps the container running in the foreground: docker run <image-name> -t -d
It wasn't obvious to me coming from a Powershell background.
if you want to operate on the container, you need to run it in foreground to keep it alive.
There are multiple options out there to run the container in foreground/detached state. But if you still feel the issue is not resolved, you can try troubleshooting the issue by viewing the logs.
sudo docker logs -f >> container.log
additionally you can also use --details to show extra details provided to logs.
Incorrect Path to App in Dockerfile:
I was migrating an application from a RHEL server to a Docker container using Alpine Linux.
No errors during the build, so I was surprised to see the container immediately exit!
First port of call:
docker logs <containerID>
This revealed the path of the binary I had supplied to CMD in the Dockerfile was bogus:
line 0: /sbin/postfix: not found
Well that told me how things were broken, but not specifically where: I still required the correct path for the binary in Alpine Linux...
Troubleshooting:
Googling didn't reveal the correct path to it, so I added the following line to my Dockerfile:
RUN which postfix
I then reviewed my build logging- provided by the below command appended to my build command- to retrieve the value of RUN which postfix
--progress=plain > /path/to/build.log 2>&1
The Fix:
I deleted this test build, supplied the correct path- /usr/sbin/postfix - to CMD in the Dockerfile, deleted RUN which postfix and ran another build.
Voila; the process now remained up.
So a duff path was causing the container to immediately exit...
These 4 commands all work to keep your docker container running:
docker run -td centos
docker run -dt centos
docker run -t -d centos
docker run -d -t centos
Firstly, You need to check if any container is running
Type command,
docker ps -all
If any container is running then stop them
Type command,
docker stop Container Id
Now, Finally run the docker by using below command..........
docker run -t -p 2020:3000 dockerImageName
Hence, Open your google chrome and visit on localhost:2020
Congrats :)

How do I run a command on an already existing Docker container?

I created a container with -d so it's not interactive.
docker run -d shykes/pybuilder bin/bash
I see that the container has exited:
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
d6c45e8cc5f0 shykes/pybuilder:latest "bin/bash" 41 minutes ago Exited (0) 2 seconds ago clever_bardeen
Now I would like to run occasional commands on the machine and exit. Just to get the response.
I tried to start the machine. I tried attaching. I thought I could call run with a container, but that does not seem to be allowed. Using start just seems to run and then exist quickly.
I'd like to get back into interactive mode after exiting.
I tried:
docker attach d6c45e8cc5f0
But I get:
2014/10/01 22:33:34 You cannot attach to a stopped container, start it first
But if I start it, it exits anyway. Catch 22. I can't win.
In October 2014 the Docker team introduced docker exec command: https://docs.docker.com/engine/reference/commandline/exec/
So now you can run any command in a running container just knowing its ID (or name):
docker exec -it <container_id_or_name> echo "Hello from container!"
Note that exec command works only on already running container. If the container is currently stopped, you need to first run it with the following command:
docker run -it -d shykes/pybuilder /bin/bash
The most important thing here is the -d option, which stands for detached. It means that the command you initially provided to the container (/bin/bash) will be run in the background and the container will not stop immediately.
Your container will exit as the command you gave it will end. Use the following options to keep it live:
-i Keep STDIN open even if not attached.
-t Allocate a pseudo-TTY.
So your new run command is:
docker run -it -d shykes/pybuilder bin/bash
If you would like to attach to an already running container:
docker exec -it CONTAINER_ID /bin/bash
In these examples /bin/bash is used as the command.
So I think the answer is simpler than many misleading answers above.
To start an existing container which is stopped
docker start <container-name/ID>
To stop a running container
docker stop <container-name/ID>
Then to login to the interactive shell of a container
docker exec -it <container-name/ID> bash
To start an existing container and attach to it in one command
docker start -ai <container-name/ID>
Beware, this will stop the container on exit. But in general, you need to start the container, attach and stop it after you are done.
To expand on katrmr's answer, if the container is stopped and can't be started due to an error, you'll need to commit it to an image. Then you can launch bash in the new image:
docker commit [CONTAINER_ID] temporary_image
docker run --entrypoint=bash -it temporary_image
Some of the answers here are misleading because they concern containers that are running, not stopped.
Sven Dowideit explained on the Docker forum that containers are bound to their process (and Docker can't change the process of a stopped container, seemingly due at least to its internal structure: https://github.com/docker/docker/issues/1437). So, basically the only option is to commit the container to an image and run it with a different command.
See https://forums.docker.com/t/run-command-in-stopped-container/343
(I believe the "ENTRYPOINT with arguments" approach wouldn't work either, since you still wouldn't be able to change the arguments to a stopped container.)
I had to use bash -c to run my command:
docker exec -it CONTAINER_ID bash -c "mysql_tzinfo_to_sql /usr/share/zoneinfo | mysql mysql"
Creating a container and sending commands to it, one by one:
docker create --name=my_new_container -it ubuntu
docker start my_new_container
// ps -a says 'Up X seconds'
docker exec my_new_container /path/to/my/command
// ps -a still says 'Up X+Y seconds'
docker exec my_new_container /path/to/another/command
If you are trying to run shell script, you need run it as bash.
docker exec -it containerid bash -c /path/to/your/script.sh
This is a combined answer I made up using the CDR LDN answer above and the answer I found here.
The following example starts an Arch Linux container from an image, and then installs git on that container using the pacman tool:
sudo docker run -it -d archlinux /bin/bash
sudo docker ps -l
sudo docker exec -it [container_ID] script /dev/null -c "pacman -S git --noconfirm"
That is all.
Pipe a command to docker exec bash stdin
Must remove the -t for it to work:
echo 'touch myfile' | docker exec -i CONTAINER_NAME bash
This can be more convenient that using CLI options sometimes.
Tested with:
docker run --name ub16 -it ubuntu:16.04 bash
then on another shell:
echo 'touch myfile' | docker exec -i ub16 bash
Then on first shell:
ls -l myfile
Tested on Docker 1.13.1, Ubuntu 16.04 host.
I would like to note that the top answer is a little misleading.
The issue with executing docker run is that a new container is created every time. However, there are cases where we would like to revisit old containers or not take up space with new containers.
(Given clever_bardeen is the name of the container created...)
In OP's case, make sure the docker image is first running by executing the following command:
docker start clever_bardeen
Then, execute the docker container using the following command:
docker exec -it clever_bardeen /bin/bash
I usually use this:
docker exec -it my-container-name bash
to continuously interact with a running container.
Assuming the image is using the default entrypoint /bin/sh -c, running /bin/bash will exit immediately in daemon mode (-d). If you want this container to run an interactive shell, use -it instead of -d. If you want to execute arbitrary commands in a container usually executing another process, you might want to try nsenter or nsinit. Have a look at https://blog.codecentric.de/en/2014/07/enter-docker-container/ for the details.
Unfortunately it is impossible to override ENTRYPOINT with arguments with docker run --entrypoint to achieve this goal.
Note: you can override the ENTRYPOINT setting using --entrypoint, but
this can only set the binary to exec (no sh -c will be used).
For Mac:
$ docker exec -it <container-name> sh
if you want to connect as root user:
$ docker exec -u 0 -it <container-name> sh
Simple answer: start and attach at the same time. In this case you are doing exactly what you asked for.
docker start <CONTAINER_ID/CONTAINER_NAME> && docker attach <CONTAINER_ID/CONTAINER_NAME>
make sure to change <CONTAINER_ID/CONTAINER_NAME>
I am running windows container and I need to look inside the docker container for files and folder created and copied.
In order to do that I used following docker entrypoint command to get the command prompt running inside the container or attach to the container.
ENTRYPOINT ["C:\\Windows\\System32\\cmd.exe", "-D", "FOREGROUND"]
That helped me both to the command prompt attach to container and to keep the container a live. :)
# docker exec -d container_id command
Ex:
# docker exec -d xcdefrdtt service jira stop
A quick way to resume and access the most recently exited container:
docker start -a -i `docker ps -q -l`
An easy solution that solved a similar problem for me:
docker run --interactive --tty <name_of_image>

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